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Adoption Potential and Perceptions of Reduced Tillage among Organic Farmers in the Maritime Pacific Northwest

mer, 2013/06/12 - 14:23

eOrganic authors:

Dr. Andrew T. Corbin Ph.D., Agriculture and Natural Resources Faculty, Washington State University Extension Snohomish County

Dr. Douglas P. Collins Ph.D., Small Farms Extension Specialist, WSU Center for Sustaining Agriculture and Natural Resources

Dr. Rose L. Krebill-Prather Ph.D., Research Associate, Social and Economic Sciences Research Center, Washington State University

Chris A. Benedict M.S., Agriculture and Natural Resources Faculty, Washington State University Extension Whatcom County

Dr. Danna L. Moore Ph.D., Interim Director, Social and Economic Sciences Research Center, Washington State University

Want to reduce your tillage? Find out what Northwest growers are learning.

Reduced tillage (RT) is a desired yet challenging strategy to achieve for many organic farmers. In the maritime Pacific Northwest, organic RT systems are not widely adopted due to the required technologies and practices that are new to producers in this region. The lack of adoption of these practices provides a unique opportunity to examine producer perceptions about soil quality and barriers to adoption of new soil improvement techniques. During the spring of 2011, three organic vegetable producer focus groups were conducted in western Washington to learn about producer knowledge, attitudes, practices, and the perceived benefits and risks of implementing RT technologies. Focus group participants were eager to share their experiences relative to organic RT practices. Farmers reported to understand the benefits of tillage reduction and cover cropping, but acknowledged there are significant obstacles to overcome before successful implementation can occur on their own farms. The obstacles encompass aspects of organic vegetable production in the maritime Northwest where there is higher soil moisture, a shorter growing season, and smaller scale farms relative to other regions where the RT practices are used successfully. While RT methods improve soil quality, farmers lose the beneficial aspects of tilling the soil related to aeration, soil moisture levels, soil temperature, and weed management. Other concerns pertained to the equipment needed for the RT practices and whether the equipment has been cost-effectively adapted to smaller scale farms. Results from these focus groups have assisted our team to more effectively proceed with RT research and outreach efforts.

Tractor in a recently rolled field

Cover crops (barley) terminated by flail mower and roller/crimper (pictured) in preparation for vegetable transplants at the Washington State University Northwest Research and Extension Center, Mount Vernon, WA. Photo credit: Andrew Corbin

Introduction

Washington State has the third highest number of organic farmers and the second highest organic farmgate sales in the United States (United States Department of Agriculture [USDA]-National Agricultural Statistics Service [NASS], 2010). Organic agriculture in western Washington is a vibrant and growing industry composed of more than 266 certified organic farms and 25,900 certified acres, up 140% and 280% respectively since 2005 (Kirby and Granatstein, 2012). Growth in western Washington organic agriculture is driven by strong consumer demand in regional metropolitan areas such as Portland, OR, Seattle, WA, and Vancouver, B.C.

Without access to synthetic pesticides and fertilizers, organic farmers are more reliant on cultural management tactics and healthy soils to manage weeds and provide fertility. In addition to a relatively short growing season common to other northern latitude regions, maritime Pacific Northwest farms experience high winter rainfall that encourages erosion, soil nutrient leaching, and soil compaction. These conditions, which escalate the risk of decreasing soil quality and ultimately profitability among organic farmers in this region, may encourage adoption of alternative production strategies.

Weed management is a primary concern for organic vegetable growers (Walz, 2004). Crops and weeds fill the same ecological niche and compete for the same resources. To be productive, growers need to structure an environment that is beneficial to the crops, with minimal weed pressure (Di Tomaso, 1995). In conventional agriculture, herbicides are used to suppress weeds, but most selective herbicides are not permitted in organic farming (Gruber and Claupein, 2009). Primary tillage (plowing/disking) and secondary tillage (cultivation) are methods of suppressing weeds compatible with organic production standards. Most research on reduced tillage (RT) systems has focused on conventional agriculture where herbicides are used (Kaval, 2004). Recent work suggests organic production systems may successfully maintain yields under higher weed pressures as compared to conventional systems (Ryan et al., 2009).

Certified organic growers must use tillage and cultivation practices that “maintain or improve the physical, chemical, and biological properties of soil” (USDA-National Organic Program [NOP], 2000). Frequent tillage contributes to the deterioration of soil quality, which threatens the sustainability of western Washington organic vegetable farms. Regular tillage with multiple passes is a routine practice of growers who rely on tillage to suppress weeds. Unfortunately, over-tilling damages soil structure and promotes erosion (Montgomery, 2008). Frequent tilling also requires labor, machinery and fuel, and expensive inputs that have negative environmental impacts (Grandy et al., 2006; Grandy and Robertson, 2006; Robertson et al., 2000). High biomass, mechanically terminated cover crop mulches associated with RT have been shown to inhibit weeds (Altieri et al., 2011; Mirsky et al., 2011; Ryan et al., 2011). Therefore, researchers are interested in evaluating RT production systems to help farmers improve the economic and environmental sustainability of their operations.

Farms provide regionally important ecosystem services (Costanza, 1997), including flood protection, erosion prevention, increased biodiversity, and carbon sequestration. RT organic farms have fewer negative externalities and more positive externalities in the form of enhanced ecosystem services (Kocian et al., 2012). Decreasing tillage activities reduces wind and soil erosion and creates benefits to society both off-site and on-site. In the United States, off-site soil erosion damage is estimated to cost $37.6 billion annually (Uri, 2001). On-site erosion impacts the future productivity of the land (Walker and Young, 1986). Farmers will also need access to machinery, whether through low-interest loans or special programs like those currently underway by Conservation Districts in Washington and Oregon, the University of Idaho, and WSU Extension (Meyer, 2009). These programs address knowledge barriers and lower risks associated with adopting new technologies by promoting communication and mentoring among farmers.

Recent research has found that traditional predictors of adoption of new innovations such as education, length of time farming, and farm structure, have little or no relationship to the adoption of more complex innovations like broader forms of conservation (Coughenour, 2003; Napier et al., 2000). Adoption of RT practices involves accepting a “loosely coupled system” composed of components that vary independently where farmers choose from a collection of practices based on their personal preferences, farm characteristics, perceived needs, level of knowledge, labor availability, and many other factors. Certain techniques may even be adapted by farmers to fit their specific farm or marketing needs. Because of the flexibility in choosing what, where, why, and how to adopt, no two organic farmers are alike in what they practice or grow. Moreover, each organic farming practice is associated with a different set of perceived adoption constraints (Goldberger, 2008). Fundamental to RT is that growers have knowledge and experiences that lead them to appreciate the complex interaction and relationships of their specific production practices and how these can impact (enhancing or eroding) soil quality and soil biology for their regional growing circumstances. An example of this is while more conventional tillage manages weeds, soil quality is reduced through greater erosion and earthworm populations decrease (Chan, 2001). Additionally, Rogers' (2003) theory of diffusion underscores the importance, advantage, and compatibility that a new technology must have in order to be widely adopted.

Preliminary experimental results and demonstration of the best methods to grow crops using RT will likely facilitate adoption of RT methods and technologies. In addition to these traditional Extension tools, adoption of conservation practices may be enhanced by internet-based outreach tools, including interactive webinars, web-pages, and web-videos (Case and Hino, 2010; Sobrero, 2008).

Coughenour (2003) found that, in adopting these more complex practices, connections between farmers may be as or more important than connections between farmers and representatives of the scientific community. In other words, conversations between farmers at the local coffee shop or feed store might be more important than the research field or laboratory. Perhaps more importantly, they rely on their peers (who have similar circumstances and similar problems) for informal “expert” consultation. This connection between farmers appears to be related to the ability of other farmers to model implementation of new practices, to talk about it in a way that is easily understood, and to potentially be available for appropriate and immediate help. On-farm trials and demonstration projects can be used to develop expertise among early adopters. Recent economic research has also shown that adoption can be better understood by looking at the demand for specific traits or qualities in complex technologies (Useche et al., 2009). It is also necessary to account for factors that go beyond profitability, including land ownership, scale of production, farm/farmer characteristics, and the life cycle of existing capital–all of which help explain why technologies are not adopted even when it appears they would improve profitability (Isik, 2004; Purvis et al., 1995; Carey and Zilberman, 2002; Barenklau and Knapp, 2007).

Developing a Reduced Tillage Research and Extension Project in Western Washington

Research and Extension efforts to reduce tillage on organic farms in western Washington began in 2008 with the formation of a stakeholder advisory group, an on-farm trial, and a symposium. The symposium, supported by a USDA Organic Research and Extension Initiative (OREI) planning grant, brought together 72 regional organic vegetable growers, agricultural professionals, and national RT specialists. National and regional organic RT specialists were invited to present successful examples and discuss their RT organic production methods. The first day culminated with a field trip to an on-farm trial. The second day focused on understanding local needs and opportunities, and describing how WSU should be involved in research and outreach. Three priorities were identified by the group: 1) Identify production methods that integrate cover crops and RT technologies to improve soil quality and reduce weed populations; 2) Evaluate the economic impact of adopting RT technologies in terms of average profitability, the variance of profits, and factors influencing the likelihood of adoption; 3) Facilitate adoption of RT technologies and ideas, and identify the most effective strategies for encouraging behavior change. Core members of the producer advisory group formed during the symposium have remained engaged as research participants in on-farm and research center trials and have guided the direction of the project to ensure relevance.

Washington Organic Farmer RT Focus Groups

Focus groups were chosen at this stage because they are a useful way to examine grower beliefs and perceptions, and to understand the decisions made on operations. Focus groups are an effective method for interacting with stakeholders and engaging them to learn more broadly about their concerns, knowledge, experiences, and barriers to implementation of RT (Krueger and Casey, 2000; Morgan and Krueger, 1998). The discussion format and what individuals had to say in response to our questions and topics provided information about their attitudes, beliefs, behaviors and their underlying values with respect to RT implementation in agriculture as well as in the high moisture areas where they manage their small to medium size organic vegetable production systems. The goal of the focus groups was to help the project team identify major bridges and barriers in the design, adoption and dissemination of RT production systems for organic vegetable crops in western Washington.

In spring 2011, the RT Working Group, made up of western Washington Extension and research faculty, worked collaboratively with faculty and staff of the WSU Social & Economic Sciences Research Center (SESRC) in the development of the focus group pre-survey, moderator's guide, focus group participant screening and selection, as well as the implementation of focus group sessions.

Focus Group Participants

For focus groups to be an effective methodology, participants need to be randomly recruited from the target population to achieve a mix of contributors comprised of the types of producers to which the research is directed (Krueger and Casey, 2000; Morgan and Krueger, 1998). Both men and women often work in small farming operations. Furthermore, there is an ethnic diversity of people who participate in area Extension programs for organic vegetable production. Specifically, western Washington has an increasing number of Latino growers involved in organic vegetable production. Focus groups with culturally diverse populations that encompass a much smaller proportion of growers and who are concentrated in some local areas more than others have not been elaborated in the literature for focus groups or Extension programs. In this research, Latino growers participated and engaged in the same session discussions with other area growers about the use of RT.

The RT Working Group provided the SESRC with a list of growers who participated in the 2009 symposium entitled “No-Till Organic Vegetable Production in Western Washington”. These farmers, along with a list of organic vegetable producers gathered from the Washington State Department of Agriculture were selected from the following western Washington counties: Whatcom, Skagit, Snohomish, King, Pierce, Thurston, Lewis, Mason, Jefferson, Clallam, Kitsap, Island, and San Juan (Fig.1). Other names suggested by WSU Extension personnel involved in the project from the counties of interest were provided to the SESRC for a total of 145 potential farmers for screening and selection.

Participants were screened for the person on the farm who makes decisions regarding cropping practices and other farm management decisions and who was 18 years of age or older. Participants also needed to have at least one acre of organic vegetables produced on their farm, but they did not have to be certified organic. The goal for each session was to have approximately ten individuals confirmed for each session.

County map of Washington that shows selected sites

Figure 1 Western Washington Counties and focus group locations

Implementation of Focus Groups

In spring 2011, focus groups were scheduled in three different locations in western Washington: Mount Vernon, Everett, and Olympia (Fig. 1). Each focus group session was planned for a two hour block of time. One of the SESRC principal investigators served as the focus group moderator while the other principal investigator took notes. In addition, audio recordings were taken during each focus group. The focus group moderator guided the discussion through the main topic areas (Table 1). The same set of topics was used at each focus group session to ensure consistency. A written pre-survey with questions about farm characteristics and a self-rating of RT knowledge was completed by farmers prior to the discussion. Farmers were also given a $50 honorarium for their participation.

 

Table 1. Focus Group Discussion Topics 1. From your perspective, what are the main reasons farmers use reduced tillage practices? What tillage practices do you currently use? 2. What are the main reasons farmers use cover crops? What cover crop practices do you currently use? 3. What concerns do you have about adopting reduced tillage practices and cover cropping? Identify any barriers. 4. What tillage equipment do you currently have? What new equipment would be needed in order to adopt reduced tillage practices? 5. How does your access or lack of access to the proper equipment affect your willingness to adopt new practices? 6. How do you learn about new farming practices? What factors influence you to make changes in your practice? 7. What factors/facts would most convince you to adopt reduced tillage practices?

At the Mount Vernon focus group, a Spanish speaking interpreter provided a simultaneous translation for the four Spanish-speaking participants during the discussion. The translator relayed their comments and questions to the larger group and then provided back discussion comments. This allowed for an interchange that offered insight into their unique practices and perceptions of RT and also allowed them to learn about and ask questions of their English-speaking grower counterparts.

Project researchers from the RT working group played a key role in the discussion by interjecting information and clarifying critical points regarding the current project-related research. Researchers also answered questions and provided clarification on RT and cover cropping practices. The sessions encouraged communication between researchers and participants by developing questions that led the conversation around the chosen topics. Farmers from this working group were committed to supporting and promoting the comprehensive resources being developed during this integrated research and Extension project.

Compilation of Findings

After the focus group sessions were completed, SESRC personnel prepared typed transcripts of each session. The data generated from the focus groups is qualitative. The power in focus groups is not a quantitative measurement but rather capturing the breadth of the topics and issues that surface from participants interacting with each other in dialogue during the sessions. Focus groups are a way to listen to people and learn from them. Often the synergy, group dynamic and questions that participants pose to one another in addition the moderator's questions explores new depths and aspects not often uncovered in surveys or other means of capturing interview data.

Results Participant Profile

In the pre-survey, the majority of participants across focus groups indicated familiarity with RT practices and though most were not using the specific strategies being studied by the RT Working Group, they have tried to reduce the amount of tillage they do in one form or another (Table 2). Twelve Mount Vernon participants, six Everett participants, and six Olympia participants indicated they have used some form of RT on their farm, although the focus group discussion revealed that individual farmers' definition of RT ranged widely. The remaining participants from each of the three locations indicated “No”; they have not used RT practices on their farm. However, all participants indicated a high level of interest in RT for various reasons.

Farmer participants rated their own current level of knowledge about RT in organic vegetable production. While these results have too few respondents to be considered a survey with statistical representation, the rating does provide a profile and guide as to how much session participants knew with regard to RT. There were no strong differences among participants in the 3 local areas in terms of RT knowledge. Mount Vernon and Everett participants rated themselves as having moderate knowledge overall, while Olympia participants tended to rate themselves with a little less than “Moderate knowledge” overall. Most of the session participants were aware there is more knowledge to be gained and that they could increase their knowledge about RT technologies and practices.

Table 2.   Focus Group Session dates, Locations, Participants, Farm Composition, and Crops Produced

      Key Focus Group Themes

The focus group discussions revealed that farmers were eager to share their experiences and were interested in learning how to effectively use these RT and cover cropping practices on their own farms. Farmers recognize there are downsides to not tilling the soil and were concerned whether or not the downsides might outweigh the advantages. Farmers also had concerns about whether RT practices would work in their particular situation in the maritime Northwest.

Bridges to Reduced Tillage and Cover Cropping: Improved Soil Quality

Soil quality was the main reason given for pursuing RT and cover cropping practices. Farmers perceived that tilling the soil destroys soil macrofauna and decreases organic matter–both important components of soil health. Farmers were interested in practices that would help to maintain and restore the balance of organic matter in the soil. On ground that has been repeatedly tilled, farmers understood they risk losing soil fertility and organic matter along with large organisms that are important to healthy soil. They also understood that maintaining and building organic matter helps to reduce erosion and regulate soil moisture.

Farmers recognized how rich the soil is when it is first tilled (i.e. when taken out of pasture), but also how quickly it loses its rich quality and organic matter when it is repeatedly tilled. Farmers worried about the number of passes they make through the field because of the probable decline in soil quality. For example, the development of a compacted hard pan has become a problem for some farmers.

Farmers wanted to know how to use RT practices to restore, maintain and improve the quality of the soil that has been compromised after repeatedly being tilled. A key question surfaced towards directing extension research: Is there a rotation strategy for using RT that will decrease soil bulk density and increase soil organic matter without losing the benefits of tillage?

Growers recognized the value of RT for maintaining soil quality but also the potential for reducing costs. One large grower in particular summarized that the fewer tillage passes he has to make through a field or bed, the more he saves on fuel and labor.

Barriers to Using Reduced Tillage Practices

No current regional examples. One of the main barriers to adopting RT was the lack of RT practices adapted to the maritime Northwest. In this area there are different crops, different soil types, different climate, and a shorter growing season compared to other areas where RT practices are currently being used successfully. Farmers were unaware of any examples of RT practices employed in areas similar to their particular situation. As a result, farmers did not feel confident about using the practices.

The scale of the operation impacted the tradeoffs farmers see between tilling and reducing tillage. Farmers wanted to know if RT and cover cropping practices used on Midwestern row crops and grains can be successfully adapted to a small intensive scale in the maritime Northwest.

For growers to be willing to adopt new practices such as RT, they want to see their risk reduced by systematic trials in research and then proven in actual farming conditions and on sites under organic vegetable production. Some growers wanted to see the results of sowing two or more cover crops. Others suggested a need for research to target cover crops that improve soil quality in wet conditions. They recognized that cover crops and RT use are not a “one size fits all” solution.

Managing soil moisture and temperature. One of the main challenges that farmers in the maritime Northwest face is high levels of soil moisture in the spring and areas on their farms that are prone to flooding because of the high levels of moisture. While some farmers indicated that cover cropping protects their soil from erosion, other farmers find that cover cropping is impractical with extremely wet soils (e.g. some farmers have standing water at critical planting times).

Farmers indicated that they were concerned about using RT practices when they have such cool spring soil temperatures because of the shorter growing season in the maritime Northwest. They stipulated that one of the main methods to increase the soil temperature is to till the soil. Furthermore, by having a lighter colored cover crop on top of dark soil, the increase in soil temperature will also be delayed.

Nutrient availability. Farmers were concerned that the nutrients incorporated into the soil during the tilling process would instead be tied up in the cover crop. They wanted to know how to get the nutrients back into the soil. While cover crops increase the organic matter and nutrients in the soil, farmers want to know how those nutrients are incorporated into the soil and become available to the targeted cash crop if the cover crop is not tilled in. Farmers are concerned that an unincorporated cover crop competes for or even drains nutrients out of the soil. Farmers want to know how RT and cover cropping impacts the main crops they are trying to grow. They want to know if there are certain combinations and timings of cover crops that will help compensate for the amount of nutrients that may be tied up in the cover crop.

Weed and pest management. Farmers indicated that they need to know how to address weed problems that may occur as tillage is reduced because they have heard that RT increases the need for herbicides. When planting beans, for example (at least without a no-till drill), there is a need to open up the row and plant the seed. This allows weeds to germinate and it is difficult to control them without further tillage or herbicides. Perennial weeds are also seen to infest ground that is fallow or has not been regularly tilled.

Slugs are another pest specific to the maritime Northwest. Farmers in the group were very concerned, as they have experienced increased slug problems if crop debris was left in the field or if a cover crop was not tilled into the soil. They expressed apprehension that cover crops, especially dense cover, may become an enhanced habitat for slugs which are already a problem.

Adoption of Reduced Tillage and Cover Cropping: Next Steps

Farmers wanted more information about which cover crops to use, how to space the plantings and more about scheduling the planting of the cover crop. One problem farmers have is being able to get the cover crop in early enough to get maturity before having to get their cash crop planted on time. Are there cover crops that have an earlier season that would work well for the farmers in the maritime Northwest? Farmers wondered if there are methods of double cropping of a cover crop with the cash crop. They also wanted to know how to coordinate multiple factors and how to get various practices to work together. Furthermore, because the methods of farming differ for different ways of marketing the products, farmers wondered whether or not these practices will work in their situation. For some cash crops, leaving cover crop “trash” in the field diminishes the value of the cash crop (e.g. green beans).

Equipment Acquisition and Utilization

Specialized equipment was mentioned as a main obstacle in each focus group. Farmers wanted to know more about the specific equipment they would need under a RT system and whether existing equipment could be adapted for RT purposes. Farmers had reservations about purchasing equipment if it was unclear whether it was adaptable to their specific situation and conditions or had a proven track record. Some also inquired as to where to find the specialized equipment. Farmers also considered the feasibility of sharing, renting, or purchasing the specialized equipment.

Growers and researchers discussed the possibility that Extension and Conservation Districts should be explored as resources for cooperative equipment sharing for small growers in a region. The participants' past experiences indicated that often there is such a short window of opportunity when specialized equipment is needed that everyone would need the equipment at the same time, and they foresee that factor as a real limitation. Also, when sharing equipment, farmers wondered who would be responsible for expenses when it breaks down. In addition, just getting the equipment from one farm to another could be a challenge. Equipment sharing can also lead to weed and plant disease problems being transmitted from one farm another.

Conclusions

This series of focus groups provided insight into the perceptions, experiences, and concerns of organic vegetable growers in western Washington. Several recurring concepts in the focus groups have been valuable in directing current and future research on RT and cover cropping practices: 1) the problems organic vegetable growers face with RT in moist maritime conditions, 2) what they want and need to know about RT to adopt it, and 3) the desire for a wider understanding of the possible benefits that accrue from RT use. The size of the sessions in terms of participants allowed for in-depth discussions about RT and cover crops, and this provided insights for guiding researchers in developing protocols that can be used to yield generalizable research results. Participants questioned each other and also questioned researchers at the end of the sessions.

Smaller growers and larger growers viewed the use of RT and cover crops differently. Small-scale Latino/a growers emphasized that since they often hand pick crops, they can use cover crops combined with RT to help keep berries clean (less soil from muddy conditions) and allow them to remain on the vine longer. Larger growers emphasized their need to carefully evaluate the tradeoff of cover crops and RT to difficulty in harvesting (weed entanglement from increased growth in subsequent seasons), changes in hand harvesting, labor and fuel costs as well as any pervasive impacts to product quality.

Focus group participants recognized the benefits of RT and cover cropping but were yearning for more information and stronger evidence of how well the RT practices proposed by researchers would work on their specific farms under their specific conditions and on their specific crops. These growers seek the benefits of the increased soil quality that can occur when tillage is reduced. However, growers have concerns about how well those practices will work for them because of the wetter climate and subsequently wetter soil they are dealing with compared to other areas where these practices are being used successfully. The performance of RT technologies during the shorter growing season in western Washington and overall cooler soil temperatures was also an important concern.

Opportunities for Future Research

Many gaps exist in RT knowledge that impede the adoption of these practices in this region. There is a clear need to understand the trade-offs between the benefits and costs associated with specific RT practices and cover crops used in terms of soil quality, weed management, soil compaction and aggregation, soil temperature, labor requirements and changes associated with proposed practices in fields with high levels of moisture in early spring. Many also indicated that because of their small scale, some specific practices and the specialized equipment in particular will need to be adapted to their situation. Growers have ongoing concerns about weeds and other pests, and about which cover crops work best and when to plant them. Slug control and prevention in RT systems is a key area of research needed in the cool, seasonally wet climate of the maritime Pacific Northwest. This is of special concern for organic growers committed to minimal or no chemical options for pest control.

Grower participants welcomed the opportunity to exchange information with fellow growers about each other's current cover cropping, crop management and tillage practices and to tap into, ask questions and learn about the current WSU research being done on RT and cover cropping practices. They were also interested in learning about some of the specialized equipment and specific practices that are being used. Very few agricultural policies are directed towards supporting small-acreage vegetable growers, and this study points to a need for specialized support and research in the form of shared equipment resources or programs to help offset risk and larger expenses. Another area of research is the role of incentives for reduced environmental impact and how that might play towards inducing organic vegetable growers to further adopt RT and cover crops to reduce soil erosion.

Growers indicated that they use a variety of ways to learn about new practices including workshops, conferences, face-to-face meetings with researchers and other growers, the Internet, YouTube™ videos and books. Growers wanted to know that the practices have been tried in real settings and under conditions similar to their own situations. Inclusion and participation by Latinos in our sessions suggests a need for materials to be translated and made available and accessible in other languages.

The WSU RT Working Group in western Washington has incorporated the valuable findings of the focus groups into their research station and on-farm experimental designs, especially in the areas of cover crop type, variety, and timing, combinations of cover crops and cover crop termination methods and timing. The Working Group continues to involve their stakeholders in workshops, trainings, field days and conferences developed specifically to influence the wider adoption of RT technologies and practices. The focus group sessions highlight that small producers have limited time, capacity, and resources to experiment and test various cover crops and tillage practices during their production season. Research programs like that of the RT Working Group have an important role to address the questions raised in a systematic way using scientific practice and experimental methods towards reducing risk for farmers to adopt RT technologies and practices.

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  • Benedict, C., A. T. Corbin, A. Bary, and D. P. Collins. 2012. Organic reduced tillage in the Pacific Northwest. Group website under the eOrganic Community of Practice for eXtension. (Available online at: http://eorganic.info/node/4988). (Verified 28 May 2013).
Acknowledgements

This project was supported by the Organic Research and Extension Initiative of the (formerly) Cooperative State Research, Education and Extension Service, USDA, Grant # 2009-51300-05584 and is gratefully acknowledged. The authors wish to thank Colleen Burrows for her role in grant and focus group development, SESRC staff and all of our farmer cooperators who participated in the focus groups.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 9597

Organic No-Till Grain Production in the Midwest

mar, 2013/06/04 - 17:23

eOrganic authors:

Kathleen Delate, Extension Organic Specialist, Iowa State University, Ames, IA

Cynthia Cambardella, Soil Scientist, USDA-ARS National Lab for Agriculture and the Environment, Ames, IA

Jeff Moyer, Farm Manager, Rodale Institute, Kutztown, PA

Introduction

Organic grain production, including soybeans, reached 1,072,107 acres in the United States in 2008 (United States Department of Agriculture [USDA] Economic Research Service [ERS], 2012). The majority of U.S. organic grain is produced in the Midwest, where in 2008 there were 374,302 acres of organic corn and 93,567 acres of organic soybeans.

The majority of organic grain producers in the Midwest rely on tillage operations to manage weeds, using rotary hoes or harrows for over-the-row weed management and row cultivators for between-row management. While tillage operations can be very effective, there has been some concern about the potential negative impact of tillage operations on soil quality–particularly for producers interested in participating in USDA Natural Resource Conservation Service [NRCS] soil conservation cost-share programs that focus on mitigating soil erosion. In order to meet certified organic requirements and enter the expanding organic market, producers must implement a soil-building plan in accordance with sections 205.203 and 205.205 of the National Organic Program (NOP) final rule (USDA, 2000). At the heart of the regulations is the protection or enhancement of carbon and other nutrients in soil organic matter to maintain soil fertility and structure.

Successful weed management is also critical for organic and transitioning farmers. Cover crops serve a dual role of providing fertility and helping to manage weeds. They can be plowed under prior to grain crop planting, or terminated without tillage in reduced tillage or no-till operations.

There is wide acceptance of no-till in conventional production systems that rely on herbicides, but it is still sometimes more difficult to get consistent crop stands in no-till compared to tilled conventional systems because of cold soil and increased insect and disease pressure on emerging seedlings. No-till is even more challenging in organic systems because organic-compliant seed treatments to protect seedlings from insects and diseases are limited, and organic-compliant herbicides are expensive to use on a broad scale and less effective than synthetic herbicides. If weeds emerge through the crushed cover crop mulch, there are limited options; however, high residue cultivation can be used to aid in managing weeds. 

This article reports preliminary research findings on no-till organic systems.

Nutrient Cycling and Cover Crops

Management of soil organic matter (SOM) to enhance soil quality and supply nutrients is a key determinant of successful organic farming. This involves balancing two ecological processes: mineralization of carbon (C) and nitrogen (N) in SOM for short-term crop uptake; and sequestration of C and N in SOM pools for long-term maintenance of soil quality, including structure and fertility.

Using organic amendments, crop rotations, and cover crops are multifunctional management practices that conserve soil organic matter, enhance soil quality, protect soil from erosion, and sequester C to help mitigate global climate change. Nitrogen fertility is maintained through synchronization of N mineralization from soil organic N pools, and plant uptake of inorganic N. Leguminous cover crops provide short-term yield benefits through rapid mineralization of inorganic N from plant biomass. Decomposing cereal grain cover crop biomass immobilizes soil N to reduce N leaching loss during the winter months, and contributes relatively more C as stabilized soil organic matter than legumes. Including small grain and leguminous cover crops in organic rotations may help optimize soil N cycling to enhance productivity and minimize loss of N from the rooting zone.

The intensive tillage that is often used in organic production can compromise soil quality gains, unless more C-rich amendments are added (manure, cover crops, compost, etc.) than are lost through decomposition. Reducing tillage in organic farming systems is a major challenge for producers because of its central role in weed management. The development of effective reduced tillage methods across a range of climates and farming systems is key to improving the environmental and economic sustainability of organic production.

Reduced Tillage of Cover Crops for Soil Health and Weed Management

Reduced tillage of cover crops in organic no-till systems has become the goal of many organic producers in the United States. Following the lead of conventional no-till systems, organic producers recognize the benefits of reduced tillage on soil physical, chemical and biological properties. No-till cover crop termination methods developed for organic systems include mowing, stalk-chopping and undercutting—all of which can lead to patchy distribution and rapid breakdown of the mulch—providing more opportunities for weed establishment and growth. Rolling or compressing the cover crop with a no-till roller/crimper can help to uniformly deposit cover crop residue and allow for a more persistent mulch cover throughout the growing season (Creamer and Dabney, 2002; Morse, 2001).

With the support from a USDA Conservation Innovation Grant [CIG], the Rodale Institute (Kutztown, PA) distributed no-till roller/crimpers to several U.S. universities in 2005 to help develop site-specific recommendations for no-till organic production (Hepperly, 2007). The roller consists of a large steel cylinder (10.5 ft wide x 16 in diameter) filled with water to provide 2,000 lbs of weight. Steel blades are welded in a chevron pattern to crimp and mechanically kill fall-planted cover crops in the spring (see Fig. 1). The roller can be rear-mounted or, more ideally, front-mounted on a tractor to crush cover crops and plant crop seeds in a single pass of the tractor. A dense, uniform cover crop is needed to create a mulch capable of suppressing weeds to avoid or greatly reduce the need for additional weed control, such as high-residue cultivation, throughout the season. Corn and soybean seeds can be planted or drilled into the flattened cover crop, using no-till planters or drills. Successful production of organic corn, soybean, tomatoes, pumpkins, and strawberries has been achieved with rolled cover crops in Pennsylvania and Michigan (Sayre, 2005). Visit Rodale Institute's webpage for organic no-till for additional information. Despite several successes, there have been many challenges with the organic no-till system (Carr et al., 2012), particularly with failure of cover crop termination (Delate et al., 2012) and cover crop residue impeding placement of supplemental fertilizers (Mirsky et al., 2012).

Man on tractor

Figure 1. Rolling/crimping rye cover crop before planting organic soybeans. Photo credit: Kathleen Delate, Iowa State University.

Organic No-Till Roller/Crimper Research in the Midwest Basic No-Till Operations

Organic no-till for corn and soybean production has been studied across the Midwest since 2005.  At the Iowa State University Neely-Kinyon Farm in Greenfield, Iowa, cover crop combinations of hairy vetch and rye (HV/R), and Austrian winter pea and winter wheat (AWP/WW), were planted in September through October and killed with a roller/crimper in late May of the following year. Rolling/crimping took place when the rye and wheat covers were at or past anthesis or pollen-shedding, and the vetch and peas were at full bloom. The hairy vetch/rye combination provided superior mulch cover over the wheat/pea mixture due to greater biomass and stand. In the first year of the experiment, organic soybeans yielded 45 bushels/acre in the hairy vetch/rye system—an excellent yield considering no post-planting tillage operations for weed management were employed (Delate et al. 2011).

A six-state (IA, MN, WI, MI, ND and PA) USDA National Institute of Food and Agriculture [NIFA] Organic No-Till Project was initiated in 2008 following a wheat crop planted on plots in all states to create a uniform crop history. Cover crops in the no-till experiment were established in fall 2008 and consisted of the following treatments: 1) a conventionally tilled treatment where cover crops (hairy vetch and rye) were planted in fall and tilled in spring, with tillage used after commercial crop planting for weed management; and 2) a no-till treatment where cover crops were planted in fall and rolled/crimped in spring with no further tillage. Plot size varied across states based on available land, averaging 30 x 100 feet with 4 replications per treatment. In May or June (weather-dependent), cover crops were either disked in the conventional tillage system, or rolled/crimped in a one-pass organic no-till system. Commercial crops of corn (following hairy vetch) and soybean (following rye) were planted with the goal of the crushed cover crops serving as a dried mulch between crop rows throughout the season. Cover crop performance was excellent: rye biomass averaged 8,952 pounds per acre across 5 sites, and hairy vetch biomass averaged 4,118 pounds per acre across 4 sites. All sites experienced some hairy vetch winter-kill, but the northernmost states (MN and ND) reported severe hairy vetch winter-kill, thus making this cover crop of limited use for organic no-till in these states.

Yields Under Organic No-Till Systems

The no-till system worked well for soybean in the crushed rye in all states when rye was rolled/crimped at or post-anthesis (see Fig. 2). Organic soybean yields averaged 26 bushels per acre in the first season without any post-planting weed management, compared to 33 bushels per acre in the conventional tillage system, which averaged 3 post-planting weed tillage operations (see Fig. 3).

The no-till corn system was much more challenging. There was only one state (PA) where no-till organic corn yields exceeded 100 bushels per acre. The corn yield average over the remaining sites was only 33 bushels per acre, compared to 73 with conventional tillage. The low corn yields overall were associated with poor overwintering of the hairy vetch cover crop in all states; a wet, cool season; high weed populations; and low nutrient availability, since the corn crop relied solely on N from the hairy vetch with no compost or manure added to the experiment.

In the majority of sites, weeds were greater in the hairy vetch/corn no-till system than the conventional tillage system. Perennial weeds were particularly problematic in the organic no-till system after one full season without tillage. The weed population was not censused prior to planting the cover crop, so it is unknown if previous weed populations aggravated the weed problem. Although weeds appeared to be less of a problem in the early-season no-till soybean plots, presumably from the rye’s thick, weed-free mulch, the rolling/crimping appeared to stimulate reproductive growth of secondary tillers. By the end of the season, the no-till soybean plots had many rye plants between soybean rows. While not critically impacting soybean yield, the presence of the rye plants at the end of 2009 led to interference with the growth of the oat crop that followed soybean in the rotation in 2010. Oats were no-till drilled, in keeping with the no-till protocol of the long-term experiment.

rolled/crimped rye cover crop with soybeans planted in one-pass operation

Figure 2. View of rolled/crimped rye cover crop with soybeans planted in one-pass operation. Photo credit: Kathleen Delate, Iowa State University.

Lower yields in no-till oat plots were associated with perennial weeds such as Canada thistle, dandelion, quackgrass and clovers; and resurgence of previously planted hairy vetch and rye cover crops. Because of the high weed populations, plots were tilled at the end of the second year after two crop-years of no-till corn or soybean followed by no-till oats, before drilling cover crops for the second no-till phase. In the second no-till corn and soybean phase, despite similar corn plant populations (no-till: 25,690 plants per acre; conventional tillage: 24,904 plants per acre), no-till corn yields again disappointed cooperators, with no-till yields only 37% of conventional tillage yields. These results strongly suggest that Midwest conditions are not conducive to successful organic no-till corn with hairy vetch as the sole source of N. Soybean plant populations in the second no-till season were 4,000 plants per acre less than in the conventional tillage system, but yields did not suffer. Cold, wet weather led to slow germination of seed, but similar yields were obtained in no-till and conventional tillage organic soybean fields, averaging 25 bushels per acre across 5 sites. Broadleaf weed populations were much greater in no-till fields, but annual and perennial grass weeds were not as high in oat, corn and soybean fields, suggesting that these crops are reasonably competitive with grass weeds in the no-till system. Despite high weed populations, no-till soybean yields were competitive, suggesting excellent compensatory function from high planting populations and extensive pod set.

organic soybeans emerging in rolled/crimped rye cover crop

Figure 3. Close-up of organic soybeans emerging in rolled/crimped rye cover crop. Photo credit: Erin Silva, University of Wisconsin-Madison.

Soil Quality Effects of Organic No-Till Production

Prior to cash crop planting at the beginning of the Organic No-Till project, soil quality analysis revealed no significant differences in any parameters between the no-till and the conventional tillage fields. After 3 years of no-till, soil microbial biomass carbon (MBC) values were significantly greater in no-till than in conventional tillage plots at 4 of the 5 relatively moist sites located in the upper and central Midwest, and PA. In ND, where rainfall was only 17 inches per year, MBC did not increase in no-till plots (Table 1). These findings could be explained by noting that MBC quickly reacts to soil management changes as experienced with the no-till treatment, since reduced soil disturbance from no-till and higher available C concentration in the top soil layer has been shown to lead to increased microbial populations. In addition, higher microbial biomass content is generally considered an indicator of soil fertility, despite lower yields in the no-till treatment. 

Table 1. Microbial biomass carbon (MBC) soil differences between no-till and conventional-till (mg/g). Analysis conducted by S.L. Weyers, USDA-ARS, Morris, MN.

Site MBC MBC Signif. Diff.*/**   No-till (NT) Conventional-till (CT)   Iowa 176 134 ** Minnesota 191 166 * Pennsylvania 138 118 ** Wisconsin 247 171  ** Michigan 105 93 NS North Dakota 96 116 Signif. greater in CT

* Significantly greater at <0.10.  ** Significantly greater at <0.05.

At 3 sites (IA, MI, and MN), residual soil nitrate-N, pH, and electrical conductivity were greater under no-till than conventional tillage. At only one of 6 sites (IA), bulk density was higher and macroaggregation lower under no-till, suggesting increased soil compaction. However, bulk density was not significantly different at half of the sites, and was significantly higher under conventional tillage at 2 sites (MN and PA), indicating that no-till management had differential effects on soil compaction for the sites under investigation. Total soil N and potentially mineralizable N were higher under no-till at the WI research station site, demonstrating enhanced cycling and storage of soil N. Because soil quality changes take multiple years to document, further research is needed to verify possible changes induced by the different soil management and crop rotation strategies.

Economic Effects of Organic No-Till Production

Average returns to management for organic corn, oats and soybean were greater in the conventional tillage system compared to the no-till system in all years, across all sites. The potential for reduced fuel, equipment, and labor costs with no-till will encourage more organic no-till systems if production challenges can be overcome. In addition, if benefits from soil C enhancement and greenhouse gas reduction were included in the analysis of no-till systems, the economic and environmental picture would be brighter for organic systems (Singerman et al., 2011).

Conclusions

Regional differences and site-specific recommendations for organic no-till grain production will continue to be investigated across the Midwest. Growers should only try the no-till system on a small scale for several years to get experience under varying conditions before committing sizable acreage. Organic no-till soybeans have been shown to have more stable yields than no-till corn, so farmers interested in experimenting with this system should try soybeans first. It is important to note that weather plays a key role in the effectiveness of the organic no-till system—adequate moisture is needed for the commercial crop to compete with the cover crop, particularly if any cover crop regrowth occurs. Adding irrigation in dry years could dramatically improve the performance of these systems in semi-arid locations. On the other hand, late spring rains can delay rolling/crimping of the cover crop and delay planting or maturity of the commercial crop, thus leading to a lower yield. As with any new technology, several challenges remain. The goal of reducing tillage in organic systems to ameliorate C losses and reduce petroleum costs in weed management, however, propels this research forward.

References and Citations
  • Agricultural Marketing Service—National Organic Program [Online]. United States Department of Agriculture. Available at: http://www.ams.usda.gov/nop/ (verified 3 May 2013).
  • Carr, P. M., P. Mäder, N. G. Creamer, and J. S. Beeby. 2012. Editorial: Overview and comparison of conservation tillage practices and organic farming in Europe and North America. Renewable Agriculture and Food Systems 27: 2–6. (Available online at: http://dx.doi.org/10.1017/S1742170511000536) (verified 3 May 2013).
  • Creamer, N. G., and S. M. Dabney. 2002. Killing cover crops mechanically: Review of recent literature and assessment of new research results. American Journal of Alternative Agriculture 17:32–40. (Available online at: http://dx.doi.org/10.1079/AJAA20014) (verified 3 May 2013).
  • Delate, K., D. Cwach, and C. Chase. 2011. Organic no-tillage system effects on organic soybean, corn and irrigated tomato production and economic performance in Iowa, USA. Renewable Agriculture and Food Systems 27:49–59. (Available online at: http://dx.doi.org/10.1017/S1742170511000524) (verified 3 May 2013).
  • Hepperly, P., R. Seidel, and J. Moyer. 2007. Year 2006 is breakthrough for organic no-till corn yield; tops standard organic for first time at Rodale Institute. Rodale Institute, Kutztown, PA. (Available online at: http://newfarm.rodaleinstitute.org/columns/research_paul/2007/0107/notill_print.shtml) (verified 3 May 2013).
  • Mirsky, S. B., M. R. Ryan, W. S. Curran, J. R. Teasdale, J. Maul, J. T. Spargo, J. Moyer, A. M. Grantham, D. Weber, T. R. Way, and G. G. Camargo. 2012. Conservation tillage issues: Cover crop-based organic rotational no-till grain production in the mid-Atlantic region, USA. Renewable Agriculture and Food Systems 27:31–40. (Available online at: http://dx.doi.org/10.1017/S1742170511000457) (verified 3 May 2013).
  • Morse, R. D. 1999. No-till vegetable production–its time is now. HortTechnology 9:373–379. (Available online at: http://horttech.ashspublications.org/content/9/3/373.full.pdf+html) (verified 3 May 2013).
  • Reganold, J. P. 1988. Comparison of soil properties as influenced by organic and conventional farming systems. American Journal Alternative Agriculture 3(4):144–155. (Available online at: http://dx.doi.org/10.1017/S0889189300002423) (verified 3 May 2013).
  • Sayre, L. 2005. Organic no-till research spreading across the Midwest. The Rodale Institute, Kutztown, PA. (Available online at: http://www.newfarm.org/depts/notill/features/2005/0602/msuroller.shtml) (verified 3 May 2013).
  • Singerman, A., K. Delate, C. Chase, C. Greene, M. Livingston, S. Lence and C. Hart. 2011. Profitability of organic and conventional soybean production under ‘green payments’ in carbon offset programs. Renewable Agriculture and Food Systems. 27:266–277. (Available online at: http://dx.doi.org/10.1017/S1742170511000408) (verified 3 May 2013).
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This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 7681

Topdressing Organic Hard Winter Wheat to Enhance Grain Protein

mar, 2013/06/04 - 13:43

eOrganic author:

Dr. Ellen Mallory Ph.D., University of Maine

Introduction

Topdressing, an in-season application of nitrogen, is a strategy some organic winter wheat growers use to increase grain yield and enhance protein. Because there is little research-based information available on topdressing, it can be difficult to decide when it is needed, appropriate timing of application, and what materials should be used.


Photo credit: Ellen Mallory, University of Maine.

Wheat Grain Protein

Grain protein is a key quality measure for bread wheat, affecting gluten strength and loaf volume. Wheat grain must have a protein concentration of 12% or greater to be considered suitable for bread flour. Grain that does not meet the acceptable level either receives a discounted price or must be sold into alternative markets. High protein wheat is often rewarded with premium payments. More information about grain protein and other bread wheat quality measures can be found in the publication Understanding Wheat Quality: What Bakers and Millers Need, and What Farmers Can Do.

Nitrogen Fertility and Grain Protein

Nitrogen (N) is a primary building block of protein, so it follows that N availability is one of the critical factors influencing the protein content of a crop. The timing of N availability, as well as the total amount, is important. Nitrogen taken up by the plant during its vegetative period can increase both yield and protein, whereas N available after stem elongation primarily increases grain protein concentration. Production practices that increase yields without supplying enough additional N can reduce grain protein concentrations due to protein dilution, i.e.,the same amount of N is contained in a greater quantity of grain. For these reasons, assuring adequate available N for grain yield and protein is a top challenge for winter wheat production. Winter wheat yields tend to be higher than spring wheat yields, yet N supply can be lower due to loss over the winter months of N applied before seeding. In conventional winter wheat production, a standard recommendation is to include a spring topdress application of N to increase grain protein content and baking quality. For more information, see Nitrogen Management for Hard Wheat Protein Enhancement.

Organic winter wheat producers face additional N fertility challenges. The most economical and practical approach to supplying N is to incorporate amendments prior to seeding. However, amendment sources with low C:N ratios (e.g. green manures and liquid dairy manure) may release substantial N in the fall and promote vegetative growth and tiller production; yet excess soil mineral N is susceptible to leaching over the winter. Sources with higher C:N ratios (e.g. solid dairy manure) may have better synchrony with fall crop uptake, but may not mineralize quickly enough in the spring to supply adequate N for the crop to attain acceptable grain protein levels. Many researchers have observed lower grain protein and bread loaf volumes for organic compared with conventional wheat, which they attributed to inadequate N supply (Annett et al., 2007; Casagrande et al., 2009; Fredriksson et al., 1997; Gooding et al., 1993).

While some organic producers use topdressing, there is limited research-based information currently available as to the best N sources and timing of application in organic systems. A study in France found that topdress applications of guano or feather meal, applied to winter wheat at various times from early tillering to heading, always produced higher gross margin from increases in grain yield, grain protein or both as compared with a no nitrogen reference treatment when there were no other limiting factors (e.g. weeds, disease, water); and that later topdress applications produced greater increases in protein than earlier ones for both materials (David et al., 2005). A similar study in the United Kingdom observed increased grain yield and grain protein with early spring applications of either broiler litter, cattle slurry, or pig slurry to winter wheat but found a high degree of variation in their effectiveness from year to year, as well as among the manures (Nicholson et al., 1999). High rates of topdress N were applied and evaluated as a sole source of N in both cases, which may not be practical for many organic farmers. See below for links to current research on using topdressing as a supplement to preplant N applications to boost grain protein levels of organic winter wheat.

Topdress Nitrogen Sources

Manure is not generally an acceptable N source for topdressing bread wheat because there may not be enough time between application and harvest to satisfy the 90-day pre-harvest interval specified in Part 205.203 of the United States Department of Agriculture [USDA] National Organic Program [NOP] regulations for crops whose edible portion does not have direct contact with the soil surface or soil particles. Other N sources for topdressing include properly composted or heat-treated/processed manures, plant and animal meals and emulsions (e.g. soybean meal, feather meal, blood meal, fish emulsion), and sodium nitrate.

Any topdressing materials must meet input standards for organic certification (see Can I Use This Input on My Organic Farm?). Sodium nitrate, also known as Chilean nitrate, is currently allowed under NOP standards but has been under scrutiny and may be restricted in the future. See the eXtension article Organic Soil Fertility for more information on different N sources for organic production.

Topdress sources can be applied as dry materials or as liquid foliar sprays, the latter being well-suited for irrigated systems depending on the liquid formulation. While soil-applied N is absorbed via plant roots, foliar-applied N may be absorbed directly through the leaf cuticle and/or indirectly via plant roots, as some of the N solution reaches the soil&emdash;either initially or with subsequent rainfall or irrigation. Foliar N application rates are limited by how much the leaves can physically absorb at any one time, and by the potential for leaf-burn from high N concentrations.

Topdress Rates

Topdress N rates depend on the yield potential of the crop. The higher the potential yield, the greater the additional N needed to increase protein. Researchers in the Pacific Northwest estimate that to achieve 14% grain protein, hard red winter wheat requires 0.4 pounds of N per bushel of grain above the amount of N needed to attain optimal yields (Brown et al., 2005). This amounts to 20 lbs N/acre for a 50-bushel per acre crop and 30 lbs N/acre for 75 bushels per acre. It is difficult to predict crop yield potential and protein increase resulting from added N since both depend on late-season growing conditions. Field and production history, including N credits for legumes used in soil-building crop rotations, should be used to help gauge if topdressing is needed and how much topdress N to apply. In conventional systems, in-season diagnostic tests at two key wheat developmental stages have been developed to guide topdress N decisions. Tiller density at spring green-up (Feekes 2) is used to determine if topdress N is needed at that time to stimulate more tillering and optimize yields. Tissue N concentration at jointing (Feekes 4-5) is used to determine if the plants have sufficient N for good protein levels or if topdress N is needed. For more information see Alley et al., 1999; Brown et al., 2005; Weisz and Knox, 2009. These tools have yet to be adapted to organic systems.
The type of topdress material applied also needs to be factored into the application rate. Materials that mineralize slowly may need to be applied at higher rates, but care should be taken to synchronize N release with crop uptake as much as possible to avoid excess N mineralization after crop harvest.

Topdress Timing

Topdress N can be applied as soon as soil conditions allow traffic on the field in early spring. However, numerous studies under conventional production have shown that later applications increase protein more than earlier ones. Similar results were found in an organic field trial of different topdress timing and N sources conducted in Maine and Vermont in 2010 and 2011. Averaged over both sites and years, topdress N applied at the late tillering, flag leaf, and boot stages increased crude protein by 0, 0.4, and 0.8 percentage points, respectively, for dehydrated chicken manure and 0.4, 0.9, and 1.3 percentage points, respectively, for sodium nitrate (Mallory and Darby, in press). In drier areas, late-season topdress N applications may not be fully utilized by the crop without adequate soil moisture. There is also concern that N applied very late in the season (at flowering and later) may increase grain protein levels but does not always improve baking quality. A number of studies in conventionally grown wheat have found no improvement in dough properties or bread loaf volume with application of a foliar urea solution at flowering despite increases in grain protein concentrations (Gooding and Davies, 1992). There is evidence that N taken up by the plant this late in the season does not get fully incorporated into functional grain proteins (Finney et al., 1957), and changes the protein composition in ways that negatively affect dough properties (Timms et al., 1981).

Economics

The decision of whether or not to topdress should include consideration of the added costs and potential returns. Topdress costs include the cost of the N product and application, and any damage that may occur to the crop from field traffic. Potential returns from topdressing depend on changes in yield, increase in protein, and whether the higher protein level moves the wheat crop from the feed-grade market to the food-grade market, or qualifies it for a protein premium when sold.

Research on Topdressing Organic Winter Wheat

The following links will take you to abstracts and recorded presentations.

References and Citations
  • Annett, L. E., D. Spaner, and W. V. Wismer. 2007. Sensory profiles of bread wheat made from paired samples or organic and conventionally grown wheat grain. Journal of Food Science 72:S254-S260. (Available online at: http://dx.doi.org/10.1111/j.1750-3841.2007.00331.x) (verified 2 May 2013).
  • Alley, M. M., P. Scharf, D. E. Brann, W. E. Baethgen, and J. L. Hammons. 2009. Nitrogen management for winter wheat: Principles and recommendations. Publication 424-026. Virginia Cooperative Extension, Blacksburg, VA. (Available online at: http://pubs.ext.vt.edu/424/424-026/424-026.html) (verified 2 May 2013).
  • Brown, B., M. Westcott, N. Christensen, B. Pan, and J. Stark. 2005. Nitrogen management for hard wheat protein enhancement. PNW 578. University of Idaho, Moscow, ID. (Available online at: http://www.cals.uidaho.edu/edcomm/detail.asp?IDnum=1270) (verified 2 May 2013).
  • Casagrande, M., C. David, M. Valantin-Morison, D. Makowski, and M. H. Jeuffroy. 2009. Factors limiting the grain protein content of organic winter wheat in south-eastern France: a mixed-model approach. Agronomy for Sustainable Development 29:565-574. (Available online at: http://dx.doi.org/10.1051/agro/2009015) (verified 2 May 2013).
  • David, C., M. H. Jeuffroy, F. Laurent, M. Mangin, and J. M. Meynard. 2005. The assessment of Azodyn-Org model for managing nitrogen fertilization of organic winter wheat. European Journal of Agronomy 23:225-242. (Available online at: http://dx.doi.org/10.1016/j.eja.2004.08.002) (verified 26 May 2013).
  • Finney, K. F., J. W. Meyer, F. W. Smith, and H. C. Fryer. 1957. Effect of foliar spraying on Pawnee wheat with urea solutions on yield, protein content, and protein quality. Agronomy Journal 49:341-347. (Available online at: http://dx.doi.org/10.2134/agronj1957.00021962004900070001x) (verified 26 May 2013)
  • Fredriksson, H., L. Salomonsson, and A. C. Salomonsson. 1997. Wheat cultivated with organic fertilizers and urea: Baking performance and dough properties. Acta Agriculturae Scandinavica, Section B—Soil & Plant Science 47:35-42. (Available online at: http://dx.doi.org/10.1080/09064719709362436) (verified 26 May 2013).
  • Gooding, M. J. and W. P. Davies. 1992. Foliar urea fertilization of cereals: A review. Nutrient Cycling in Agroecosystems 32:209-222. (Available online at: http://dx.doi.org/10.1007/BF01048783) (verified 26 May 2013).
  • Gooding, M. J., W. P. Davies, A. J. Thompson, and S. P. Smith. 1993. The challenge of achieving breadmaking quality in organic and low input wheat in the UK—A review. Aspects of Applied Biology 36:189-198.
  • Mallory, E., T. Bramble, M. Williams and J. Amaral. 2012. Understanding wheat quality: What bakers and millers need and what farmers can do. Bulletin 1019. University of Maine Cooperative Extension, Orono, ME. (Available online at: http://umaine.edu/publications/1019e/) (verified 26 May 2013).
  • Mallory, E. and H. Darby. In-season nitrogen effects on organic hard red winter wheat yield and quality. Agron Journal. In press.
  • Nicholson, F.A., B.J. Chambers, K.A. Smith, and R. Harrison. 1999. Spring applied organic manures as a source of nitrogen for cereal crops: experiments using field scale equipment. The Journal of Agricultural Science 133:353-363. (Available online at: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=7517) (verified 26 May 2013).
  • Timms, M.F., R.C. Bottomly, J.R.S. Ellis, and J.D. Schofield. 1981. The baking quality and protein characteristics of a winter wheat grown at different levels of nitrogen fertilisation. Journal of the Science of Food and Agriculture 32:684-698. (Available online at: http://dx.doi.org/ 10.1002/jsfa.2740320709) (verified 26 May 2013).
  • Weisz, R. and B. Knox. 2012. Nitrogen management for small grains. In R. Weisz (ed.) Small Grain Production Guide 2011-2012. AG-580. North Carolina Cooperative Extension Service, Raleigh, NC. (Available online at: http://www.smallgrains.ncsu.edu/production-guide.html) (verified 26 May 2013).


 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 7694

May 2013

mar, 2013/05/21 - 17:33
In this Issue Recently Published eOrganic Articles

Current and Future Prospects For Biodegradable Plastic Mulch in Certified Organic Production Systems, by Andrew T. Corbin, Carol A. Miles, Jeremy Cowan and Debra A. Inglis of Washington State University;  Douglas G. Hayes of the University of Tennessee, and  Jennifer Moore-Kucera of Texas Tech University. This article explains how biodegradable plastic mulches are made; how biodegradability is measured; current techniques on evaluating biodegradable mulches; and research and policy progress to date. The purpose is to inform agricultural professionals, farmers, and policy makers about the suitability of biodegradable plastic mulches for use in certified organic agriculture.Read more at http://www.extension.org/pages/67951

Producer Profiles in Organic Dairy, published by the eOrganic Dairy Team, is a series of farm case studies which track financials as farms transitioned to certified organic production. The case studies were originally written as part of a multi-year study led by University of Vermont economists Robert Parsons and Qingbin Wang that focused on the profitability of New England organic dairy farms. Three farm case studies are provided; they can be found at: http://www.extension.org/pages/59468

Records Needed for Organic Poultry Certification, by Devon Patillo of CCOF and Jacquie Jacob of the University of Kentucky. This is the first in a series of upcoming eOrganic articles on organic poultry production. This article provides an introduction to poultry recordkeeping requirements for compliance with National Organic Program rules. Find the article at http://www.extension.org/pages/67936

Using Cover Crops in Organic Systems: Resources and Research from SARE by Andy Zieminski, SARE. This article provides information on some of the many free online resources on cover crops available from the Sustainable Agriculture Research and Education (SARE) program, which has funded hundreds of research and education projects related to cover crops since 1988. SARE’s Cover Crop Topic Room features free information products (books, bulletins, webinars, etc.) and research projects relevant to both conventional and organic production. Find the article at http://www.extension.org/pages/67876

New eOrganic Dairy Webinars

Organic Dairy Forages: Focus on Summer Annuals by Heather Darby, University of Vermont Extension and Rick Kersbergen, University of Maine Extension. May 23 at 2PM Eastern (1PM Central, 12PM Mountain, 11AM Pacific Time). Join us for this free webinar on summer annual forages--including millet, sorghums, sorghum-sudans, and teff. These grains can be important complements to pastures during the summer slump as well as harvested for stored feed. The presenters will discuss strategies for planting, harvesting, and feeding these forages to organic dairy cattle. Register in advance at http://www.extension.org/pages/68106

Amending Soils in the Organic Dairy Pasture, by Cindy Daley, California State University, Chico. June 27th at 2PM Eastern (1PM Central, 12PM Mountain, 11AM Pacific Time).  In this free webinar, Dr. Daley will describe a long-term soil remediation field trial designed at the University Farm to study the effects of a basic soil amendment program on forage quality and yield, with an emphasis on the economic return that would result from added milk production. Register in advance at http://www.extension.org/pages/68131

More dairy webinars will be offered over the summer, and our main webinar season will start up again in the fall. Meanwhile, feel free to listen to any of the many webinars on organic farming and research in our archive at http://www.extension.org/pages/25242  You can also browse the recordings by topic here.

Organic News

CERES Trust Report on Organic Research and Outreach in the North Central Region

CERES Trust has issued a new report on Organic Research and Outreach in the North Central Region, which includes information on organic programs and research in Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin. The report contains brief descriptions of recent and current organic research projects, peer-reviewed papers, and extension publications, dating back to 2002 when US National Organic Program (NOP) regulations took effect. In addition, the report lists key contact people and describes academic courses, degree programs, and hands-on learning opportunities, such as student organic farms, and much more. Find the report on the CERES Trust website, where it will be updated annually. It has also been published on eXtension.org.

NOP News

On April 2nd, The National Organic Program (NOP) announced the availability of draft guidance on Classification of Materials (NOP 5033) and Materials for Organic Crop Production (NOP 5034).  These guidances are intended as tools for material reviewers and growers to help determine which substances are allowed in organic production and products. Public comments on these materials are being accepted until June 3, 2013. Links to these and other proposed guidances which are currently open to public comment can be found on the NOP website where you can also find direct links to online comment forms. Subscribe to the NOP Organic Insider to stay current on NOP news and activities.

eOrganic Mission

eOrganic is a web community where organic agriculture farmers, researchers, and educators network; exchange objective, research- and experience-based information; learn together; and communicate regionally, nationally, and internationally. If you have expertise in organic agriculture and would like to develop U.S. certified organic agriculture information, join us at http://eorganic.info

eOrganic Resources

Find all eOrganic articles, videos and webinars at http://extension.org/organic_production

Connect with eOrganic on Facebook and Twitter, and subscribe to our YouTube channel!

Have a question about organic farming? Use the eXtension Ask an Expert service to connect with the eOrganic community!

 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8741

Plant Breeding in Organic Farming Systems

sam, 2013/05/18 - 04:49

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic T870

Amending Soils in the Organic Dairy Pasture

mar, 2013/05/14 - 12:21

Join eOrganic for a webinar on Thursday, June 27, 2013 at 2 pm Eastern Time (1 pm Central, 12 noon Mountain, 11 am Pacific Time) on research results about amending soils in organic dairy pastures.

The webinar is free and open to the public. Space is limited. Advance registration is required.
Reserve your Webinar Seat Now at: https://www1.gotomeeting.com/register/404019096

About the Webinar

In organic dairy systems, the adage, "it all starts with the soil" means that high forage intake and optimal milk production rely on maintaining good soil fertility. Investing in your soils can actually provide returns that continue to pay "dividends" long after the deposit is made into the proverbial soil bank account. Making that initial investment was an important step in the organic evolution of the certified acreage at the University Farm at Calfornia State University, Chico. In this webinar, Dr. Cindy Daley will describe a long-term soil remediation field trial designed at the University Farm to study the effects of a basic soil amendment program on forage quality and yield, with an emphasis on the economic return that would result from added milk production.

About the Presenter

Cindy Daley is a professor in the College of Agriculture at the California State University, Chico. She received her Bachelor of Science degree in animal science at the University of Illinois and her PhD in animal science--endocrinology at the University of California, Davis. Cindy is the faculty supervisor and manager of the Organic Dairy Teaching and Applied Research Unit at CSU-Chico where, in 2007, she spearheaded the effort to transition the dairy to a certified organic operation. The farm has100 certified organic acres (including 60 acres of irrigated pasture, 10 acres in winter forage and 30 acres in alfalfa) and supports 80 cross-bred milking cows, as a seasonal system. In addition to the integrated organic livestock/cropping system, the farm also has an organic vegetable project with sales to food services on campus.

Find all upcoming and archived eOrganic webinars at http://www.extension.org/pages/25242

System Requirements

PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.6 or newer
Mobile attendees
Required: iPhone®, iPad®, Android™ phone or Android tablet

Java needs to be installed and working on your computer to join the webinar. If you have concerns, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar. If you are running Mac OS X 10.6 with Safari, please be sure to test your Java. If it isn't working, please try Firefox (http://www.mozilla.com) or Chrome (http://www.google.com/chrome).

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 9625

Organic Dairy Forages: Focus on Summer Annuals

lun, 2013/05/13 - 13:03

Join eOrganic for a webinar on Thursday, May 23, 2013 at 2 pm Eastern Time (1 pm Central, 12 noon Mountain, 11 am Pacific Time) on using summer annuals as forages for your organic dairy farm.

The webinar is free and open to the public. Space is limited. Advance registration is required.
Register at: https://www1.gotomeeting.com/register/609374329

About the Webinar

Summer annual forages--including millet, sorghums, sorghum-sudans, and teff-- can be important complements to pastures during the summer slump as well as harvested for stored feed.  Join Heather Darby and Rick Kersbergen as they discuss strategies for planting, harvesting, and feeding these forages to organic dairy cattle.

About the Presenters

Heather Darby is an agronomist at the University of Vermont Extension where she conducts applied research and outreach on farm-based fuel, forage, and grain production systems in New England. Heather's research has focused on traditional and niche crop variety trials, weed management strategies, and cropping systems development. Her farmer outreach programs have focused on soil health, nutrient management, organic grain and forage production, and oilseed production. In addition, Heather leads the eOrganic dairy team and also operates a certified organic farm with her husband in northern Vermont.

Rick Kersbergen is an Extension Professor at the University of Maine Cooperative Extension. Rick has been conducting research and extension programs related to sustainable dairy and forage systems since 1987. He is currently involved with several multi-state, applied research projects on cover crops, organic grains production, and forage and nutrient management. He is past chair of the Northeast Pasture Consortium and manages the regional website as a compendium of grazing information for the region.

Find all upcoming and archived eOrganic webinars at http://www.extension.org/pages/25242

System Requirements

PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.6 or newer
Mobile attendees
Required: iPhone®, iPad®, Android™ phone or Android tablet

Java needs to be installed and working on your computer to join the webinar. If you have concerns, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar. If you are running Mac OS X 10.6 with Safari, please be sure to test your Java. If it isn't working, please try Firefox (http://www.mozilla.com) or Chrome (http://www.google.com/chrome).

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 9624

eOrganic Webinar and Broadcast Recordings by Topic

mer, 2013/05/08 - 17:12

Find all archived eOrganic webinars and conference broadcast recordings organized by topic on this page. For a chronological listing of webinars and for upcoming webinars, go to http://www.extension.org/pages/25242

Certification

ABCs of Organic Certification, Jim Riddle, UMN

Developing an Organic System Plan for Row Crops, Beth Rota

Flooding and Organic Certification, Jim Riddle, UMN

GMO Contamination: What's an Organic Farmer to Do?, Jim Riddle, UMN

How can Organic, non-GMO and GMO Crops Coexist? Live Broadcast, Lynn Clarkson, Clarkson Grain. Broadcast live from the 2013 Illinois Specialty Crops, Agritourism and Organic Conference

National Organic Program Update, Miles McEvoy, NOP

Organic Certification of Research Sites and Facilities, Jim Riddle, UMN

Third Party Audits for Small and Medium Sized Meat Processors, Jim Riddle, Joe McCommons, and the Quality Control Manager of Lorentz Meats

Climate Change

Effects of Climate Change on Insect Communities in Organic Farming Systems, David Crowder, WSU

Greenhouse Gases and Agriculture: Where does Organic Farming fit?, David Granatstein, Lynne Carpenter-Boggs, Washington State University, Dave Huggins, WSU

Greenhouse Gas Emissions Associated with Dairy Farming Systems, Tom Richard, Gustavo Camargo, Penn State

Impact of Grain Farming Methods on Climate Change, Michel Cavigelli, USDA-ARS

Organic Agriculture - Global Contributions to Environment and Food Security. Nadia Scialabba, Senior Officer, Sustainable Development, FAO-UN, Broadcast from USDA Organic Systems Conference

Performance of Organic Treatments in Long-Term Systems Trials: Organic Benefits and Challenges in the Face of Climate Change, Erin Silva, University of Wisconsin

Shades of Green Dairy Farm Calculator, Charles Benbrook, The Organic Center

Conservation

Getting EQIPed: USDA Conservation Programs for Organic and Transistioning Farmers, Jim Riddle, UMN

Increasing Plant and Soil Biodiversity on Organic Farmscapes, Louis Jackson, UC Davis

NRCS Conservation Practices, Organic Management and Soil Health, Susan Andrews, Carmen Ugarte, Michelle Wander

NRCS EQIP Technical and Financial Support for Conservation on Organic Farms Webinar, Sarah Brown, Oregon Tilth

Using NRCS Conservation Practices and Programs to Transition to Organic, David Lamm, NRCS

Cover Crops

Assessing Nitrogen Contribution and Rhizobia Diversity Associated with Winter Legume Cover Crops in Organic Systems, Julie Grossman, NCSU

Cover Crops for Disease Suppression, Alex Stone, Oregon State

Cover Crop Selection, Jude Maul, USDA ARS

Increasing Soil Fertility and Health Through Cover Crops, Julie Grossman, NCSU

Linking Cover Crops, Plant Pathogens, and Disease Control in Organic Tomatoes, Brian McSpadden-Gardener

Estimating Plant-Available Nitrogen Contribution from Cover Crops, Nick Andrews, Dan Sullivan, Oregon State

The Evolution, Status, and Future of Organic No-Till in the Northeast US, William Curran, Penn State; Steven Mirsky, USDA; Bill Mason, Mason's Heritage Farms

Planning for Flexibility in Effective Crop Rotations, Chuck Mohler, Cornell

Optimizing the Benefits of Hairy Vetch in Organic Production, John Teasdale, USDA-ARS

The Role of Cover Crops in Organic Transition Strategies, Brian McSpadden-Gardener, Ohio State

Using Cover Crops to Suppress Weeds in Northeast US Farming systems, William Curran, Penn State Matthew Ryan, Cornell

Using Winter Killed Cover Crops to Facilitate Organic No-till Planting of Early Spring Vegetables, Mike Snow, Farm Manager, Accokeek Ecosystem Farm; Charlie White, Penn State

Dairy

A Look at the Newly Released Organic Pasture Rule, Kerry Smith, USDA, AMS, National Organic Program

Barley Fodder Feeding for Organic Dairies, John Stoltzfus, Be-A-Blessing Organic Dairy, Fay Benson, Cornell University

Breeding and Genetics: Considerations for Organic Dairy Farms, Brad Heins, UMN

The Economics of Organic Dairy Farming in New England, Bob Parsons, University of Vermont

Fly Management in the Organic Dairy Pasture, Donald Rutz, J. Keith Waldron, New York State IPM Program

Healthy Soils for a Healthy Organic Dairy Farm -- Broadcast from 2011 NOFA-NY Organic Dairy Conference, Heather Darby, University of Vermont, Cindy Daley, University of California, Chico

How to Calculate Pasture Dry Matter Intake on Your Organic Dairy Farm, Sarah Flack, Sarah Flack Consulting

Maximizing Dry Matter Intake on Your Organic Dairy Farm, Karen Hoffman, USDA-NRCS

Organic Dairy for the Next Generation. Heather Darby, University of Vermont. Broadcast from the USDA Organic Farming Systems Conference 2011.

Organic Weed Management on Livestock Pastures, Sid Bosworth, University of Vermont

Setting up a Grazing System on Your Organic Dairy Farm, Sarah Flack, Sarah Flack Consulting

Shades of Green Dairy Farm Calculator, Charles Benbrook, The Organic Center

Stockpiling Forages to Extend the Grazing Season on Your Organic Dairy, Laura Paine, Wisconsin Department of Agriculture, Trade and Consumer Protection

Supplementing the Organic Dairy Cow Diet: Results of Molasses and Flaxseed Feeding Trials, Kathy Soder, USDA-ARS

Transitioning Organic Dairy Cows off and on Pasture, Rick Kersbergen, University of Maine

Using Small Grains as Forages on Your Organic Dairy, Heather Darby, University of Vermont Extension

Your Organic Dairy Herd Health Toolbox, Hubert Karreman, Penn Dutch Cow Care

Disease Management

A Novel Strategy for Soil-borne Disease Management: Anaerobic Soil Disinfestation (ASD), Carol Shennan, UCSC, David Butler, University of Tennessee

Grafting for Disease Management in Organic Tomato Production, Frank Louws North Carolina State University Cary Rivard, Kansas State University

Grafting Tomatoes for Organic Open Field and High Tunnel Production, David Francis, Ohio State

Late Blight Control in Your Organic Garden, Meg McGrath, Cornell

Late Blight Control on Organic Farms 2010 Webinar Meg McGrath, Cornell; Sally Miller, Ohio State

Late Blight Webinar 2009, Sally Miller, Ohio State; Meg McGrath, Cornell: Alex Stone, Oregon State

Linking Cover Crops, Plant Pathogens, and Disease Control in Organic Tomatoes, Brian McSpadden-Gardener, Ohio State

Organic Methods for Control of Insect Pests and Diseases of Pecan and Peach, David Shapiro-Ilan, Clive Bock, USDA ARS

Food Safety

Microbial Food Safety Issues of Organic Foods, Francisco Diez-Gonzalez, University of Minnesota

Tracking Your Produce for Your Business and Health, Colleen Collier Bess, Michigan Dept of Agriculture

Fruit Production

Fire Blight Control in Organic Pome Fruit Systems Under the Proposed Non-antibiotic Standard, Ken Johnson, Oregon State

The OrganicA Project: Current Research on Organic Production of Ginger Gold, Honeycrisp, Zestar!, Macoun, and Liberty Apples, Lorraine Berkett, University of Vermont

Organic Blueberry Production, Bernadine Strik, Handell Larco, Oregon State University, David Bryla, USDA.

Organic Fruit Production Research. Bernadine Strik, Oregon State University, Broadcast from USDA Organic Farming Systems Conference, 2011. Broadcast from the International Organic Fruit Symposium, 2012

Organic Methods for Control of Insect Pests and Diseases of Pecan and Peach, David Shapiro-Ilan, Clive Bock, USDA-ARS

Research Update on Non-antibiotic Control of Fire Blight, Ken Johnson, Oregon State; Rachel Elkins, UC Cooperative Extension; Tim Smith, WSU Cooperative Extension

Transition to Organic Fruit Production - Impacts on Yield and Environmental Performance in a Muscadine Vineyard. Girish K. Panicker, Director, Center for Conservation Research, Alcorn State University, Broadcast from USDA Organic Systems Conference 2011.

Undercover Nutrient Investigation: The Effects of Mulch on Nutrients for Blueberry, Dan Sullivan, Ryan Costello, Luis Valenzuela, Oregon State

2nd International Organic Fruit Symposium Broadcasts, 2012

Grain Production (includes quinoa)

The "Ancient" Grains Emmer, Einkorn and Spelt: What We Know and What We Need to Find Out Frank Kutka, NPSAS, Steve Zwinger, NDSU, Julie Dawson, Cornell, June Russell, Greenmarket/GrowNYC

Barley Fodder Feeding for Organic Dairies, John Stoltzfus, Be-A-Blessing Organic Dairy, Fay Benson, Cornell University

Dryland Organic Agriculture Symposium from the Washington Tilth Conference 2011

How can Organic, non-GMO and GMO Crops Coexist? Live Broadcast, Lynn Clarkson, Clarkson Grain

Impact of Grain Farming Methods on Climate Change, Michel Cavigelli, USDA-ARS

Management for High-Quality Organic Wheat and Ancient Grain Production in the Northeast, David Benscher, Cornell, Greg Roth, Penn State, Elizabeth Dyck, OGRIN

Organic Grains. Ellen Mallory, University of Maine. Broadcast from USDA Organic Farming Systems Conference, 2011.

Organic Quinoa Production in the Pacific Northwest, Kevin Murphy, WSU

Organic Weed Management in Organic Grain Cropping Systems, Chris Reberg Horton, NCSU

Soil Fertility Management in Organic Grain Cropping Systems, John Spargo, University of Massachusetts. Broadcast from Carolina Organic Commodities and Livestock Conference, 2012.

Soil Fertility Management in Organic Wheat Production, John Spargo, University of Massachusetts. Broadcast from Carolina Organic Commodities and Livestock Conference, 2012.

Using Small Grains as Forages on Your Organic Dairy, Heather Darby, University of Vermont Extension

Wheat Mycotoxins in Organic Grain Systems, Christina Cowger, USDA-ARS and NCSU. Broadcast from the Carolina Organic Commodities and Livestock Conference, 2012.

Wheat Varietal Selection for Organic Grains in North Carolina, Chris Reberg Horton, NCSU. Broadcast from the Carolina Organic Commodities and Livestock Conference, 2012.

Hops Production

Starting Up Small-Scale Organic Hops Production, Rob Sirrine, Michigan State University, Brian Tennis, Michigan Hop Alliance

Livestock Production

Dryland Organic Agriculture Symposium from the Washington Tilth Conference 2011

Third Party Audits for Small and Medium Sized Meat Processors, Jim Riddle, Joe McCommons, Arion Thiboumery, and Erin Lohmann

Marketing

CSA Farmer's Guide to Accepting SNAP/EBT Payments, Bryan Allan, Friends of Zenger Farm

Dryland Organic Agriculture Symposium from the Washington Tilth Conference 2011

How can Organic, non-GMO and GMO Crops Coexist? Live Broadcast, Lynn Clarkson, Clarkson Grain. Broadcast live from the 2013 Illinois Specialty Crops, Agritourism and Organic Conference

Local Dirt: Beyond Marketing. Find Buyers, Sell Online, Source & Buy Product…Yourself, Heather Hilleren, Kassie Rizzo, Local Dirt

North Carolina's Statewide Initiative for Building a Local Food Economy, Nancy Creamer, Teisha Wymore, North Carolina State University

Organic Farming Financial Benchmarks, Dale Nordquist, UMN

Plan for Marketing Your Organic Products, Susan Smalley, MSU

Planning Your Organic Farm for Profit, Richard Wiswall, Cate Farm

Veggie Compass: Whole Farm Profit Management, Erin Silva, Rebecca Claypool, University of Wisconsin

Why Eat Organic: Live Broadcast from the Illinois Specialty Crops, Agritourism and Organic Conference, Jim Riddle, University of Minnesota

Pest Management

Brown Marmorated Stink Bugs, Anne Nielsen, Rutgers University

Ecological Farm Design for Pest Management In Organic Vegetable Production: Successes and Challenges on Two Farms, Helen Atthowe

Effects of Climate Change on Insect Communities in Organic Farming Systems, David Crowder, WSU

Fly Management in the Organic Dairy Pasture, Donald Rutz, J. Keith Waldron, New York State IPM Program

Integrated Pest Management in Organic Field Crops, Eileen Cullen. Robin Mittenthal, University of Wisconsin, Christine Mason, Standard Process Farm

Live Broadcast from Fly Management on Your Organic Dairy Workshop, Roger Moon, University of Minnesota; J Keith Waldron, Cornell; Wes Watson, North Carolina State University

Organic Methods for Control of Insect Pests and Diseases of Pecan and Peach, David Shapiro-Ilan, Clive Bock, USDA-ARS

Scouting for Vegetable and Fruit Pests on Organic Farms, Helen Atthowe and Doug O'Brien

Stink Bug Management with Trap Crops, Russell Mizell, University of Florida

Research Methods

On-Farm Testing: Finding What Works for Your Farm, Diana Roberts, WSU Extension from the Dryland Organic Agriculture Symposium at the Washington Tilth Conference, 2011

Participatory On-farm Research: Beyond the Randomized Complete Block Design, Sieg Snapp, MSU

Seed Production

How to Breed for Organic Production Systems, Jim Myers, Oregon State

Organic Seed Breeding for Nutrition, Philipp Simon, University of Wisconsin; Walter Goldstein, Mandaamin Institute; Jim Myers, Oregon State; Micaela Colley, Organic Seed Alliance

Sourcing Organic Seed Just Got Easier: An Introduction to Organic Seed Finder, Chet Boruff, AOSCA, Kristina Hubbard, Organic Seed Alliance

Updates from the NCSU Organic Cropping Systems Program and Growing Canola, Chris Reberg-Horton, NCSU. Broadcast from the Carolina Livestock and Organic Commodities Conference, 2012.

Using the eOrganic Organic Seed Production Tutorials, Jared Zystro, Organic Seed Alliance

The Organic Seed Grower's Conference, Port Townsend Washington: Selected Live Broadcasts

Soil and Tillage

A Novel Strategy for Soil-borne Disease Management: Anaerobic Soil Disinfestation (ASD), Carol Shennan, UCSC; David Butler, University of Tennessee

Assessing Nitrogen Contribution and Rhizobia Diversity Associated with Winter Legume Cover Crops in Organic Systems, Julie Grossman, NCSU

The Evolution, Status, and Future of Organic No-Till in the Northeast US, Bill Curran, Penn State, Steven Mirsky, USDA, Bill Mason, Mason's Heritage Farms

Estimating Plant-Available Nitrogen Contribution from Cover Crops, Nick Andrews, Dan Sullivan, Oregon State

Increasing Plant and Soil Biodiversity on Organic Farmscapes, Louis Jackson, UC Davis

Planning for Flexibility in Effective Crop Rotations, Chuck Mohler, Cornell

Reduced Tillage in Organic Vegetable Production: Successes, Challenges, and New Directions, Helen Atthowe

Researcher and Farmer Innovation to Increase Nitrogen Cycling on Organic Farms, by Louise Jackson and Tim Bowles

Root Media and Fertility Management for Organic Transplants, John Biernbaum, MSU

Soil Fertility Management in Organic Grain Cropping Systems, John Spargo, University of Massachusetts. Broadcast from Carolina Organic Commodities and Livestock Conference, 2012.

Soil Fertility Management in Organic Wheat Production, John Spargo, University of Massachusetts. Broadcast from Carolina Organic Commodities and Livestock Conference, 2012.

Undercover Nutrient Investigation: The Effects of Mulch on Nutrients for Blueberry, Dan Sullivan, Ryan Costello, Luis Valenzuela, Oregon State

Weed Management

Can we talk? Improving Weed Management Communication between Organic Farmers and Extension, Sarah Zwickle, The Ohio State University; Marleen Riemens, Wageningen University and Research Center, Netherlands

Cultivation and Seedbank Management for Improved Weed Control, Eric Gallandt, University of Maine

Organic Weed Management in Organic Grain Cropping Systems, Chris Reberg Horton,  NCSU, Broadcast from the Carolina Livestock and Organic Commodities Conference, 2012.

Organic Weed Management on Livestock Pastures, Sid Bosworth, University of Vermont

Using Cover Crops to Suppress Weeds in Northeast US Farming systems, William Curran, Penn State; Matthew Ryan, Cornell

Vegetable Production

Grafting for Disease Management in Organic Tomato Production, Frank Louws North Carolina State University Cary Rivard, Kansas State University

Grafting Tomatoes for Organic Open Field and High Tunnel Production, David Francis, Ohio State

High Tunnel Production and Low Cost Tunnel Construction, Tim Coolong, University of Kentucky

Late Blight Control in Your Organic Garden, Meg McGrath, Cornell

Late Blight Control on Organic Farms 2010 Webinar Meg McGrath, Cornell; Sally Miller, Ohio State

Late Blight Webinar 2009, Sally Miller, Ohio State; Meg McGrath, Cornell: Alex Stone, Oregon State

Linking Cover Crops, Plant Pathogens, and Disease Control in Organic Tomatoes, Brian McSpadden-Gardener, Ohio State

Organic Cropping Systems for Vegetable Production: Crop Nutrition and Environmental Effects. Kristian Thorup-Kristensen, Copenhagen University, Broadcast from USDA Organic Farming Systems Conference, 2011

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8734

Including Amaranth in Organic Poultry Diets

mar, 2013/05/07 - 12:15

eOrganic author:

Dr. Jacquie Jacob Ph.D., University of Kentucky

NOTE: Before using any feed ingredient, make sure that the ingredient is listed in your Organic System Plan and approved by your certifier.

Introduction

Amaranth has been cultivated for grain for thousands of years (Kauffman and Weber, 1990). Amaranth grain was a staple in the diet of the Aztecs and was an integral part of their religious ceremonies. As a result, when the conquistadors arrived in South America they banned the cultivation of amaranth. Amaranth continued to grow as a weed during this time; therefore, the genetic base was maintained. This allowed for the rediscovery of amaranth's potential as a food and as a feed ingredient. Technically, amaranth is not a true cereal grain and is sometimes called a pseudo-grain, an herb, or even a vegetable. There are about 60 species of amaranth. Some are grown for their spinach-like leaves, eaten as a salad. Other species are grown for ornamental or decorative purposes, and some are grown for the small seeds.

In a two-year study, Pullins et al. (1997) looked at the potential of five cropping systems in which amaranth was paired with small grains and brassicas. This study concluded that net returns were high for wheat-amaranth and canola-amaranth croppings on the basis of average yield levels. Such combinations may also decrease the incidence of pests and diseases by breaking pest cycles. The use of a winter cover crop may also reduce soil erosion with little or no added equipment costs.

Seeds

Commercial cultivars of grain amaranth became available in the late 1970s (Hackman and Myers, 2003) but its production has been limited. Increased demand for gluten-free flour has spurred more recent interest in amaranth. Amaranth is adaptable to different climates, including drought-tolerant cultivars suitable for production in the Midwest.

Protein

Amaranth seeds are unusually high in protein for a non-legume (12–18% crude protein) (Kauffman and Weber, 1990). The protein also has a well-balanced amino acid profile and is high in lysine. Amaranth seeds are said to have more balanced levels of the essential amino acids than other cereals. Corn, the most commonly used energy source in poultry diets, is rich in leucine but poor in lysine and tryptophan. Amaranth seeds have nearly twice the lysine content of wheat and three times that of corn. In fact, the levels of lysine in amaranth seeds are similar to those in milk. Amaranth is also high in methionine—another essential amino acid that is low in most grains—but is low in leucine.

Energy

The fat content of amaranth is higher than most cereal grains with 6-10% ether extract (Kauffman and Weber, 1990). The fat is also high in unsaturated fatty acids (especially the essential fatty acid linolenic acid). Amaranth also has a high content of squalene which is usually only found in liver of deep sea fish and other marine species. Squalene has been shown to reduce cholesterol synthesis. Research has shown that dietary squalene may improve the reproductive performance of broiler breeder males (Li et al., 2010). In a study using artificial insemination, supplementation with squalene increased serum testosterone level and semen collection volume but had no effect of egg fertility rate. Supplementing males in a natural mating environment, however, did increase the egg fertility rate.

Use in Poultry Diets

Use of amaranth seeds in poultry diets is limited because they contain anti-nutritional factors, including saponins, trypsin inhibitors, phytate, and tannins. The phytate content of amaranth is typically higher than that of rice and millet, but lower than that of corn and wheat (Lorenz and Wright, 1984). Tannin levels in amaranth are typically similar to those found in sorghum and millet (Lorenz and Wright, 1984). Presence of the anti-nutritional factors requires that amaranth seeds be heat-treated before they can be effectively included in poultry diets—much the same as is done with soybeans, which contain anti-nutritional factors as well. Raw amaranth cannot be included in broiler diets above 20%. However, heat-treated amaranth can be included at up to 40% in broiler and layer diets with no adverse effect on production performance (Tillman and Waldroup, 1988). Untreated amaranth grain can be used at low levels in the diet as a replacement for meat and bone meal.

Leaves

Some amaranth cultivars are grown specifically for leaf production. In China, for example, amaranth is grown specifically as forage for cattle with several cuttings occurring each season. Some types of amaranth have been shown to accumulate oxalate(s) and nitrates when grown under stress conditions (Saunders and Becker, 1984). Care should be taken, therefore, when choosing an amaranth cultivar for forage production.

Dried amaranth leaves can also be fed to chickens. They are relatively high in protein (23%) and methionine. The leaves need to be dried first to destroy heat-labile anti-nutritional factors that may be present. Enzyme supplementation (cocktail of cellulase, glucanase, and xylanase) has been shown to increase the level of dried amaranth leaves that can be included in broiler diets (Fasuyi and Akindahunsi, 2009).

Summary

Amaranth grain has the potential to partially replace corn and soybean meal in poultry diets. Unfortunately, the presence of anti-nutritional factors require that the seeds be heat-treated before being included in poultry diets. Amaranth leaves are a potential source of protein and methionine for chickens but, as with the grains, they must be heat-treated first, typically by drying.

References and Citations
  • Fasuyi, A. O., and A. O. Akindahunsi. 2009. Nutritional evaluation of Amaranthus cruentus leaf meal based broiler diets supplemented with cellulase/glucanase/xylanase enzymes. American Journal of Food Technology 4:108-118. (Available online at: http://docsdrive.com/pdfs/academicjournals/ajft/2009/108-118.pdf) (verified 23 April, 2013)
  • Hackman, D., and R. Myers. 2003. Market opportunities for grain amaranth and buckwheat growers in Missouri. Final report to the Federal-State Marketing Improvement Program.
  • Kauffman, C. S., and L. E. Weber. 1990. Grain amaranth. p. 127-139. In J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.
  • Li, S., Z. Liang, C. Wang, Y. Fend, X. Peng, and Y. Gong. 2010. Improvement of reproduction performance in AA+ meat-type male chicken by feeding with squalene. Journal of Animal and Veterinary Advances 9:486-490.
  • Lorenz, K., and B. Wright. 1984. Phytate and tannin content of amaranth. Food Chemistry 14:27-34. (Available online at: http://dx.doi.org/10.1016/0308-8146(84)90015-3) (verified 23 April, 2013)
  • Pullins, E. E., R. L. Myers, and H. C. Minor. 1997. Alternative crops in double-crop systems for Missouri. Fact sheet published by the University of Missouri-Columbia. (Available online at: http://extension.missouri.edu/p/G4090) (verified 23 April, 2013)
  • Saunders, R. M., and R. Becker. 1984. Amaranthus: a potential food and feed resource. In Advances in Cereal Science and Technology 6:357-396. American Association of Cereal Chemists, Inc., MN.
  • Tillman, P. B. and P. W. Waldroup. 1988. Performance and yields of broilers fed extruded grain amaranth and grown to market weight. Poultry Science 67:743-749. (Available online at: http://dx.doi.org/10.3382/ps.0670743) (verified 23 April, 2013)

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8100

Current and Future Prospects For Biodegradable Plastic Mulch in Certified Organic Production Systems

jeu, 2013/05/02 - 12:46

eOrganic authors:

Dr. Andrew T. Corbin Ph.D., Washington State University

Dr. Carol A. Miles Ph.D., Washington State University

Jeremy Cowan, Washington State University

Dr. Douglas G. Hayes Ph.D., University of Tennessee

Dr. Jennifer Moore-Kucera Ph.D., Texas Tech University

Dr. Debra A. Inglis Ph.D., Washington State University

Introduction

Certified organic farmers are currently allowed to use conventional polyethylene mulch, provided it is removed from the field at the end of the growing or harvest season. To some, such use represents a contradiction between the resource conservation goals of sustainable, organic agriculture and the waste generated from the use of polyethylene mulch. One possible solution is to use biodegradable plastic as mulch, which could present an alternative to polyethylene in reducing non-recyclable waste and decreasing the environmental pollution associated with it. This article explains how biodegradable plastic mulches are made; how biodegradability is measured; current techniques on evaluating biodegradable mulches; and research and policy progress to date. The purpose is to inform agricultural professionals, farmers, and policy makers about the suitability of biodegradable plastic mulches for use in certified organic agriculture. A glossary is provided at the end of this publication which includes definitions and terms commonly used when describing biodegradable plastic mulch. Terms included in the glossary are in bold text.

Plastic mulch films in agriculture

Polyethylene plastic mulch is widely used for crop production in the U.S. and worldwide, because it controls weeds, conserves soil moisture, increases soil temperature, improves crop yield and quality, has a relatively low cost, and is readily available (Schonbeck and Evanylo, 1998; Corbin et al., 2009; Miles et al., 2012). However, the sustainability of producing crops through the use of polyethylene mulch has been called into question because polyethylene mulch is made of non-renewable, petroleum-based feedstock, is generally only used for one growing season, and cannot be recycled in most regions. Recycling is limited because the mulch may be contaminated with soil and agrochemicals, specialized baling equipment is required before hauling, and facilities for recycling are often a long distance away. (Garthe and Kowal, 1993).

The high volume of waste generated by polyethylene mulches both in the field and in landfills raises many concerns (Figure 1). For example, in 2004 in the U.S., 143,000 tons of plastic mulch were disposed. While much of this waste entered the landfill at a cost to growers of up to $100 per acre, some was burned on site (Shogren and Hochmuth, 2004). Burning of polyethylene mulch can have undesirable environmental impacts, such as the release of dioxins as an airborne pollutant (Levitan, 2005; Lemieux, 1997). While there are no federal regulations restricting the open burning of plastics, the practice is banned in several states or counties in the U.S. (EPA, 2011; OAR, 2013). Utilization of polyethylene mulch by soil microorganisms in landfills is negligible, with the microbial conversion and abiotic oxidation products possibly consisting of environmentally harmful chemicals such as aldehydes and ketones (Hakkarainen and Albertsson, 2004). The use of biodegradable mulches could save significant labor and disposal costs, conserve resources, and decrease pollution (Smith et al., 2008).

 

Figure 1. (a) Typical post-season polyethylene plastic mulch waste in the field.  (b) Ready for transport to the landfill. Photo Credit: C. Miles, Washington State University. From Corbin et al., 2013.

For these reasons, both new and experimental mulches that are designed to biodegrade (mineralize) fully into carbon dioxide and water, have been developed by industry and academic institutes over the past 25 years. To be a viable alternative in organic crop production, biodegradable plastic mulch must perform comparably to polyethylene mulch, especially in regard to durability and the ability to block light to prevent weed germination. Ideally, once the biodegradable mulch's useful service life has ended, it is plowed into the soil where it should degrade. In the short-term, the mulch should lose mechanical strength and undergo a reduction in the degree of polymerization (Figure 2), or depolymerization, thereby making the polymer molecules accessible to microorganisms. Ultimately, the mulch should undergo at least 90% mineralization within a two-year period.

Figure 2. (a) Starch-based biodegradable plastic mulch (BioAgri®) in experimental field plots during harvest, 135 days after laying mulch. (b) 9 months post-harvest on soil surface, 348 days after laying mulch. (c) 9 months post-incorporation, 348 days after laying mulch. Photo Credits: J. Cowan (2a) and C. Miles (2a, 2b), Washington State University. From Corbin et al., 2013.

How are biodegradable plastic mulches produced?

Many biodegradable plastic mulches that are commercially available are films made from plant starch; these are prepared using conventional plastics processing technology. However, due to the poor mechanical properties of starch, including its brittleness, starch must be blended with other polymers and/or plasticizers. Products currently on the market that contain plant starch include Biomax TPS (DuPont, USA), Biopar (Biop, Germany), Paragon (Avebe, Netherlands), BiosafeTM (Xinfu Pharmaceutical Co., China), Eastar BioTM (Novamont, Italy), Eco-Flex® (BASF, Germany), Ingeo® (NatureWorks, USA) and Mater-Bi® (Novamont, Italy) (Hayes et al., 2012).

Two polymers that may have a future role in biodegradable plastic mulches are polylactic acid (PLA) and polyhydroxyalkanoate (PHA). PLA is a highly versatile, biodegradable polyester derived from 100% renewable resources such as corn and sugar beet starch, and offers great promise in a wide range of commodity applications (Drumright et al., 2000). Starch is converted by microorganisms into lactic acid through fermentation. Lactic acid molecules are then linked together into long chains called polymers. PLA is a relatively inexpensive biopolymer to manufacture (~ $0.95 per lb), and can be produced in large quantities (Endres and Siebert-Raths, 2011). The PLA polymer is highly attractive for biological and medical applications because it can be spun into filaments that can be used to make textiles or films (Gupta et al., 2007). PHAs are promising biodegradable plastics that have been highlighted as "green" polymers because they are made from renewable resources in a one-step process by the bacterial fermentation of sugars and/or lipids (Kaihara et al., 2005; Posada et al., 2011; Hayes et al., 2012). PHA polymers may be produced from microbes or plants; but currently, microbes are the primary source (Keshavarz and Roy, 2010).

New experimental agricultural mulches have been prepared from PLA and PHA blends using nonwovens textile technology (Wadsworth et al., in press). Nonwovens are manufactured sheets, webs or bats (wadded rolls) of directionally or randomly oriented fibers or filaments, bonded together. Nonwovens may be manufactured by spunbond or meltblown processes. In the spunbond process, polymers are first melted and then extruded through spinnerets, producing filaments which are cooled and laid down on a conveyer belt to form a web. In the meltblown process, polymers are extruded through a die or spinneret, and the filaments are stretched, dispersed, cooled, and then collected on a roll. Generally, meltblown nonwovens have smaller fiber sizes and have lower mechanical strength than spunbond nonwovens (Hayes et al., 2012).

Some processes that are used to form biodegradable polymers utilize additives, such as nucleating agents (chemical substances incorporated in plastics for the growth of crystals in the polymer melt), plasticizers, coloring agents, performance additives, and/or lubricants to improve the mechanical properties of the plastic. The environmental impact of many additives may be a major concern in organic as well as conventional crop production. Some additives are derived from petroleum and/or are chemically processed, and are therefore considered synthetic material by National Organic Program (NOP) standards (Hayes et al., 2012; NOS, 2012), which has prevented their use in U.S. organic agriculture. In addition, the NOP considers PLA to be synthetic because PLA is chemically polymerized (Briassoulis and Dejean, 2010). While the PHA polymer is made directly by microorganisms in the fermentation process (thereby considered "natural" by the NOP), it is highly crystalline, making its end product more brittle, and less desirable, unless blended with PLA or other co-polymers (Hayes et al., 2012).

What constitutes biodegradability?

Many agricultural plastics are advertised as "biodegradable"; however, such claims need to be evaluated carefully. For a manufacturer to employ the claim of biodegradability, a set of specified standards need to be met. ASTM International (formerly known as the American Society for Testing and Materials) has prepared a series of standards for "compostable plastics" to measure biodegradability under municipal or industrial composting conditions, referred to as ASTM D6400.

The ASTM D6400 specification encompasses several ASTM standardized tests, such as the "inherent biodegradability" of the plastic material via ASTM D5988-03. This test measures the microbial conversion of the plastic’s carbon (C) atoms to carbon dioxide (CO2), over time. A standard that is embedded in ASTM D6400 specifies that 90% of C atoms must be mineralized, that is, converted to CO2 within 180 days by microorganisms (ASTM, 2003). In the laboratory, CO2 release is measured through a relatively inexpensive titration method.

Biodegradability-related standards are comprised of criteria that address the following three issues:

(i) The conditions of the system —industrial-scale composting or anaerobic digestion, soil, marine, etc.
(ii) The time frame—number of days for carbon molecules in plastic to be converted to CO2.
(iii) The fraction of carbon atoms that are to be fully mineralized by microorganisms – generally expected to be at least 90%.

Many mulches claiming to be "biodegradable" are actually "compostable", i.e., able to fulfill the requirements of ASTM D6400, or related standards. Moreover, no standard currently exists for measuring the biodegradability of plastics incorporated into soil under field conditions. To meet this need for measuring biodegradability within the soil, ASTM International is developing a new standard (Work Item 29802) entitled Aerobically Biodegradable Plastics in the Soil Environment (ASTM, 2012). In this new standard, biodegradable mulches must break down into CO2, water and environmentally benign substances within one or two years, leaving no harmful residues. The ability of existing and emerging biodegradable plastic mulch films to meet these criteria in the soil environment has been the topic of several investigations (Harding et al., 2007; Hayes et al., 2012; Miles et al., 2012; Hoshino et al., 2007; Kapanen et al., 2008; Kijchavengkul et al., 2008; Kyrikou and Briassoulis, 2007; Mohee and Unmar, 2007; Tachibana et al., 2009; Wadsworth et al., 2009), and continues to be researched.

Evaluating degradation/deterioration vs. biodegradation

The term degradation is used to denote changes in physical properties caused by chemical reactions involving bond scission in the macromolecule (polymer). Biopolymer degradation includes changes of physical properties, caused not only by chemical reactions, but also by physical forces. Because the term polymer degradation involves a deterioration in the functionality of polymeric materials, "degradation" and "deterioration" are often used interchangeably (Schnabel, 1992). ASTM and the International Organization for Standardization (ISO) define degradation as an irreversible process leading to a significant change of the structure of a material, typically characterized by a loss of properties (e.g. integrity, molecular weight, structure or mechanical strength) and/or fragmentation, as affected by environmental conditions, proceeding over a period of time, and comprising one or more steps (Krzan et al., 2006).

The efficiency of the plastic degradation process varies by environment and may also be affected by the concentration of chemicals present that may react with the plastic. Environmental factors such as temperature, moisture level, atmospheric pressure, concentrations of acids and metals, and light exposure all have an effect on the rate of degradation that is due to microorganisms i.e., biodegradation (Kyrikou and Briassoulis, 2007). However, weight loss and other physical, chemical and mechanical property reductions in biodegradable plastic do not comprise the full measure of percent biodegradation unless microbial utilization of C (via CO2 conversion) is also measured. Percent biodegradation is the measure of the rate and amount of CO2 released from the total C input (from the mulch), and is a direct measure of the amount of C being utilized by the microbial community (Narayan, 2010).

While biodegradation measurements in the field or laboratory are relatively straightforward for well equipped and trained scientists, they are impractical for farmers to perform. Until the scientific community and the NOP can provide farmers with repeatable results on field performance of biodegradable plastic mulch products that are recommended for organic use, it may be advisable for farmers to monitor the degree of mulch degradability (see limitations below). Miles and others (2012) assessed percent visual deterioration (PVD) of biodegradable plastic mulch under field conditions and counted the number of rips, tears and holes (RTH) in a designated portion of the mulch twice per month. PVD proved to be a fair assessment of mulch deterioration while RTH did not. Cowan (personal communication) evaluated PVD during two late-summer broccoli seasons, and then measured mulch fragment recovery over the course of one year after mulches were tilled into the soil. At each of five sampling times, three random four-inch-diameter x six-inch-deep soil samples were collected (using a golf cup cutter) per 28-foot of mulch treated bed. Samples were sieved to retrieve mulch fragments,and photographs of mulch fragments were digitally analyzed to measure average area of individual fragments, fragment counts, and total fragment area. Findings indicated that post-tillage mulch recovery can be measured using this method. Two of the mulch products evaluated, Crown 1 and BioAgri, were recovered at 0% and 34%, respectively, within 13 months after soil incorporation.

Moore-Kucera et al., (in prep.) as part of a three-year field study, buried mesh bags containing a 4 inch square of biodegradable plastic mulch (previously weathered in the field for one growing season) and 300-400 grams of native agricultural soil four inches deep in field plots at three locations (Knoxville, TN, Lubbock, TX, and Mount Vernon, WA). At each location, one mesh bag was removed from replicated plots every 6 months for 24 months and the residual mulch pieces were evaluated for percent surface area remaining (Figure 3). Results varied widely by location, each with unique physical (light, temperature, moisture, wind, etc.), chemical (pH) and soil microbial attributes (Corbin et al., 2013; Bailes et al., in press; Moore-Kucera, 2012). For further information on experimental mulch degradation in the field, see the Washington State University Factsheet Using Biodegradable Plastics as Agricultural Mulches (Corbin et al., 2013). Although these types of field measurements will not determine percent mulch biodegradation per se, they are relatively simple sampling procedures that farmers, Extension or Agricultural Agency personnel can perform without the use of laboratory equipment, and provide a visual estimate of degradation/deterioration and mulch recovery in the field. 

Figure 3. Samples of starch-based biodegradable plastic mulch (BioTELO®) recovered after twenty-four months burial in the field at three experimental locations. Photo credit: J. Moore-Kucera, Texas Tech University.

Biodegradable plastic mulch limitations in certified organic production

In the U.S., organic crop producers have not been able to use currently available biodegradable plastic mulch products because these products did not conform to NOP standards. To be acceptable for organic production, biodegradable plastic mulch must be entirely composed of constituents derived from natural resources (bio-based), cannot contain synthetics such as petroleum-derived ingredients or additives, and cannot be chemically modified during the manufacturing process (NOS, 2012; Corbin et al., 2013; Corbin et al., 2009).

An additional requirement to meet the organic standards is that feedstocks, such as corn, used to produce the polymer, must be free of genetically modified organisms (GMOs). Similarly, any polymer made from microbial fermentation, such as PHA, must be produced by organisms that have not been genetically modified. Biodegradable plastic mulch manufacturers must certify that their feedstocks and microbial fermentation processes are GMO-free; however, there is no available test to verify GMO byproducts in the final product. While there is no specific NOP policy on GMOs in biodegradable plastic feedstock, the NOP has developed an ad-hoc committee to clarify the GMO issue.

Another requirement for use in certified organic production is that the resins and any inert additives used in the processing and formulation of biodegradable plastic mulch products must be identified and compared to the National List of allowable substances. The designation of ingredients as "proprietary" is not adequate for review and approval by the National Organic Standards Board (NOSB) – the sole authority to recommend adding or removing materials from the National List of acceptable and prohibited substances.

Finally, any biodegradable plastic mulch that may eventually be approved for use by the NOP must completely biodegrade into carbon dioxide, water, and microbial biomass within a "reasonable" timeframe without forming harmful residues or by-products. Sufficient data will be needed to verify that each biodegradable mulch is truly biodegradable in an agricultural system.

A growing contingency of manufacturers and organic farmers who wanted this interpretation of the NOP standards to be revised so that biodegradable plastic mulches are included on the National List of allowable "synthetic" substances has recently gained recognition (NOSB, 2012). As a precedent, the organic standards in Canada and the European Union (E.U.) have allowed some use of currently available biodegradable plastic mulches. In 2012, the Biodegradable Products Institute (BPI) petitioned the NOP to allow the addition of biodegradable plastic mulch under section 205.206 (c) of the National Organic Standards Biodegradable Plastic Mulch Made from Bioplastics: without removal at the end of the growing or harvest season (BPI, 2012). In October 2012, the NOSB voted 12-3 to formally recommend the NOP approve biodegradable plastic mulch in organic production (NOSB, 2012). Included in this recommendation is a requirement that organic growers take appropriate actions to ensure complete degradation (NOSB, 2012) of biodegradable plastic mulch products on their farms, underlining the importance of evaluating on-site degradation. As of 2013, the recommendation has yet to be accepted and defined by the NOP as a rule, so while these materials may be allowable in the near future, current use of biodegradable plastic mulch in U.S. certified organic production remains prohibited.

Glossary of Key Terms

Abiotic Oxidation - nonliving substances or environmental factors combined with oxygen to cause a loss of electrons.

Aldehydes - Compounds RC(=O)H , in which a carbonyl group (a functional group composed of a carbon atom double-bonded to an oxygen atom) is bonded to one hydrogen atom and to one R group or side chain (IUPAC, 1997).

Biodegradable plastic - Degradable plastic in which the degradation results from the action of naturally occurring microorganisms such as bacteria, fungi, and algae (ASTM, 2011; 2004).

Bio-based - Commercial or industrial products (other than food or feed) that are composed in whole or in significant part of biological products or renewable domestic agricultural materials (including plant, animal, and marine materials) or forestry materials (Biobased US, 2007).

Bioplastics - Form of plastics derived from renewable biomass sources, such as vegetable fats, oils or starches.

Bond scission - breakage of a chemical bond, especially one in a long chain molecule (Oxford Dictionary, 2013).

Deterioration - To weaken or disintegrate.

Degradation -  the breakdown of an organic compound.

Feedstock - Raw material that is used to supply or fuel a process.

Fermentation - The process in which cells (microorganisms, plant or animal cells) are cultured in a bioreactor in liquid or solid medium to convert organic substances into biomass (growth) or into products (IUPAC, 1997).

Genetically Modified Organism (GMO) - An organism whose genetic material has been altered using genetic engineering techniques; also referred to as a genetically engineered organism (GEO).

Inert - Stable and unreactive under specified conditions (IUPAC, 1997).

Ketones - Compounds in which a carbonyl group (a functional group composed of a carbon atom double-bonded to an oxygen atom) is bonded to two carbon atoms. (IUPAC, 1997).

Microbial biomass - Material produced by the growth of microorganisms (IUPAC, 1997).

Mineralization - Microbial conversion of organic matter into inorganic substances, such as water and carbon dioxide (Guggenberger, 2005).

PHA - Polyhydroxyalkanoates (PHAs) are a group of biologically synthesized polyesters that are considered promising eco-efficient bioplastics because they are both biobased and biodegradable, thus meeting the criteria of a closed loop life cycle (Reis et al., 2011).

PLA - polylactic acid (PLA) is a thermoplastic polymer made from lactic acid and has mainly been used for biodegradable products, such as plastic bags and planting cups, but in principle PLA can also be used as a matrix material in composites (Oksman et al., 2003).

Polyethylene - a polymer of ethylene; especially: any of various partially crystalline lightweight thermoplastics (CH2CH2)x that are resistant to chemicals and moisture.

Polymer - A molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass (IUPAC, 1997).

Polymerization - Any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer (Encyclopedia Britannica 2012).

Synthetic material (according to the USDA NOSB) - A substance that is formulated or manufactured by a chemical process or by a process that chemically changes a substance extracted from naturally occurring plant, animal, or mineral sources, except that such term shall not apply to substances created by naturally occurring biological processes (Sullivan, 2011).

References and Citations
  • ASTM International. 2012. Standard specification for aerobically biodegradable plastics in soil environment (ASTM WK29802), West Conshohocken, PA USA.
  • ASTM D 5988-03. 2003. Standard test method for determining aerobic biodegradation in soil of plastic materials or residual plastic materials after composting. ASTM International, West Conshohocken, PA USA.
  • ASTM D6400. 2004. International standard specification for compostable plastics. ASTM International, West Conshohocken, PA USA.
  • ASTM D883. 2011. International standard terminology relating to plastics. ASTM International, West Conshohocken, PA USA.
  • Bailes, G., Lind, M., Ely, A., Powell, M., Moore-Kucera, J., Miles, C., Inglis, D., and Brodhagen, M. 201x. Isolation of native soil microorganisms with potential for breaking down biodegradable plastic films used in agriculture. Journal of Visualized Experiments (accepted Oct 10, 2012).
  • BPI 2012. Support the BPI's Biodegradable Mulch Film Petition. [Online]. Biodegradable Products Institute, Inc. New York, NY.  Available at: http://www.bpiworld.org/mulchpetition (verified 30 April, 2013).
  • Briassoulis, D.; Dejean, C. 2010. Critical Review of Norms and Standards for Biodegradable Agricultural Plastics Part I: Biodegradation in Soil. Journal of Polymers and the Environment. 18 (3), 384-400. Available online at: http://openagricola.nal.usda.gov/Record/IND44454056 (verified 30 April, 2013).
  • Environmental Protection Agency. 2011. Outdoor Air: Industry, Business, and Home Backyard Trash Burning. [Online]. Available at: http://www.epa.gov/oaqps001/community/details/barrelburn.html (verified 30 April, 2013).
  • Corbin, A., Miles, C., Hayes, D., Dorgan, J., and Roozen, J. July 25–28, 2009. Suitability of Biodegradable Plastic Mulches In Certified Organic Production. American Society of Horticulture Conference, St. Louis, Missouri. Available online at: http://ashs.org/db/horttalks/detail.lasso?id=684 (verified 30 April, 2013).
  • Corbin, A.T., Miles, C., Cowan, J., Hayes, D., Dorgan, J., and D. Inglis. 2013. Using Biodegradable Plastics as Agricultural Mulches. Washington State University Extension Fact Sheet FS103E; 6pp. Available online at http://cru.cahe.wsu.edu/CEPublications/FS103E/FS103E.pdf (verified 30 April, 2013).
  • Drumright, R. E., P. R. Gruber & D. E. Henton 2000. Polylactic acid technology. Advanced Materials 12, 1841-1846. Available online at:  (verified 30 April, 2013).
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  • Endres, H.-J.; Siebert-Raths, A., 2011. Engineering Biopolymers - Markets, Manufacturing, Properties and Applications. Hanser Publishers: Munich.
  • Garthe, J.W. and P.D. Kowal. 1993. Recycling used agricultural plastics. Penn State Fact Sheet C-8. Available online at http://pubs.cas.psu.edu/freepubs/pdfs/c8.pdf (verified 30 April, 2013).
  • Guggenberger, G. 2005. Microorganisms and soil genesis. In Microorganisms in soils: roles in genesis and functions, Buscot, F.; Varma, A., Eds. Springer-Verlag: Berlin; pp 85-106.
  • Gupta, B., N. Revagade & J. Hilborn 2007. Poly(lactic acid) fiber: An overview. Progress in Polymer Science 32, 455-482. Available online at http://dx.doi.org/10.1016/j.progpolymsci.2007.01.005 (verified 30 April, 2013).
  • Hakkarainen, M.; Albertsson, A.-C. 2004. Environmental degradation of polyethylene. Advances in Polymer Science 169 (Long-Term Properties of Polyolefins), 177-199. Available online at: http://link.springer.com/chapter/10.1007%2Fb13523 (verified 30 April, 2013).
  • Harding, K. G., J. S. Dennis, H. von Blotnitz & S. T. L. Harrison 2007. Environmental Analysis of Plastic Production Processes: Comparing Petroleum-Based Polypropylene and Polyethylene with Biologically-Based Poly-B-Hydroxybutyric Acid Using Life Cycle Analysis. Journal of Biotechnology 130, 57-66. Available online at: http://www.ncbi.nlm.nih.gov/pubmed/17400318 (verified 30 April, 2013).
  • Hayes, D. G., S. Dharmalingam, L. C. Wadsworth, K. K. Leonas, C. A. Miles & D. A. Inglis. 2012. Biodegradable Agricultural Mulches Derived from Biopolymers. In Degradable Polymers and Materials, Principles and Practice, ed. A. I. Kishan C. Khemani, Carmen Scholz, University of Alabama at Huntsville. ACS Books.
  • Hoshino, A., M. Tsuji, M. Momochi, A. Mizutani, H. Sawada, S. Kohnami, H. Nakagomi, M. Ito, H. Saida, M. Ohnishi, M. Hirata, M. Kunioka, M. Funabash & S. Uematsu 2007. Study of the determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions. Journal of Polymers and the Environment 15, 275-280.  Available online at: http://link.springer.com/article/10.1007%2Fs10924-007-0078-z (verified 30 April, 2013).
  • IUPAC. 1997. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford. XML  Created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. Available online at: http://goldbook.iupac.org/ (verified 30 April, 2013).
  • Kaihara, S., Y. Osanai, K. Nishikawa, K. Toshima, Y. Doi & S. Matsumura 2005. Enzymatic transformation of bacterial polyhydroxyalkanoates into repolymerizable oligomers directed towards chemical recycling. Macromolecular Bioscience 5, 644-652. Available online at: http://www.ncbi.nlm.nih.gov/pubmed/15988790 (verified 30 April, 2013).
  • Kapanen, A., E. Schettini, G. Vox & M. Itavaara 2008. Performance and Environmental Impact of Biodegradable Films in Agriculture: A Field Study on Protected Cultivation. Journal of Polymers and the Environment 16, 109-122. Available online at: http://link.springer.com/article/10.1007%2Fs10924-008-0091-x (verified 30 April, 2013).
  • Keshavarz, T. & I. Roy 2010. Polyhydroxyalkanoates: bioplastics with a green agenda. Current Opinion in Microbiology 13, 321-326. Available online at: http://dx.doi.org/10.1016/j.mib.2010.02.006 (verified 30 April, 2013).
  • Kijchavengkul, T., R. Auras, M. Rubino, M. Ngouajio & R. T. Fernandez 2008. Assessment of aliphatic-aromatic copolyester biodegradable mulch films. Part I: Field study. Chemosphere 71, 942-953. Available online at: http://www.ncbi.nlm.nih.gov/pubmed/18262221 (verified 30 April, 2013).
  • Krzan, A., S. Hemjinda, S. Miertus, A. Corti and E. Chiellini. 2006. Standardization and certification in the area of environmentally degradable plastics. Polymer Degradation and Stability 91:2819-2833. Available online at: http://dx.doi.org/10.1016/j.polymdegradstab.2006.04.034 (verified 30 April, 2013).
  • Kyrikou, I. & D. Briassoulis 2007. Biodegradation of agricultural plastic films: A critical review. Journal of Polymers and the Environment 15, 125-150. Available online at: http://link.springer.com/article/10.1007%2Fs10924-007-0053-8 (verified 30 April, 2013).
  • Lemieux, P. M. 1997. Evaluation of emissions from the open burning of household waste in barrels. US Environmental Protection Agency Report 600/R-97-134a; Washington, DC; p 70. Available online at: http://www.ecy.wa.gov/programs/air/outdoor_woodsmoke/PDFs/EPAbarlbrn1.pdf (verified 30 April, 2013).
  • Levitan, L. 2005. Reducing dioxin emissions by recycling agricultural plastics: Creating a viable alternative to open burning. In Great Lakes Regional Pollution Prevention Roundtable, New York.
  • Miles, C., R. Wallace, A. Wszelaki, J. Martin, J. Cowan, T. Walters, and D. Inglis. 2012. Durability of potentially biodegradable alternatives to plastic mulch in three tomato production regions. HortScience 47(9):1270-1277. Available online at: http://hortsci.ashspublications.org/content/47/9/1270.abstract (verified 30 April, 2013).
  • Mohee, R. & G. Unmar 2007. Determining biodegradability of plastic materials under controlled and natural composting environments. Waste Management 27, 1486-1493. Available online at: http://dx.doi.org/10.1016/j.wasman.2006.07.023 (verified 30 April, 2013).
  • Moore-Kucera, J., M. Davinic, L. Fultz, J. Lee, C.A. Miles, M. Brodhagen, J. Cowan, R.W. Wallace, A. Wszelaki, J. Martin, J. Roozen, B. Gundersen and D.A. Inglis. 2011. Biodegradable Mulches: Short-term degradability and impacts on soil health. HortScience 46(10):S68.
  • Narayan, R. 2010. Misleading claims and misuse of standards proliferate in the nascent bioplastics industry space. Bioplastics Magazine, Polymedia Publisher GmbH. 10(1):38-41. Available online at: http://www.bioplasticsmagazine.com/bioplasticsmagazine-wAssets/docs/arti... (verified 30 April, 2013).
  • National Organic Standards (NOS) 2012. § 205.206 Crop pest, weed, and disease management practice standard. § 205.601(b)(2)(i-ii) Synthetic substances allowed for use in organic crop production. Available online at: http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=3f34f4c22f9aa8e6d9864cc2... (verified 30 April, 2013).
  • National Organic Standards Board (NOSB) 2012. Formal recommendation to classify Biodegradable biobased mulch film as synthetic and Petition to list Biodegradable biobased mulch films on §205.601(b)(2) Mulches. http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5101277 (verified 30 April, 2013).
  • Oksman K, Skrifvars M, Selin JF (2003) Natural fibres as reinforcement in polylactic acid (PLA) composites. Composites Science and Technology 63: 1317-1324. Available online at: http://dx.doi.org/10.1016/S0266-3538(03)00103-9 (verified 30 April, 2013).
  • Oregon Administrative Rules (OAR) 2013. Department of Environmental Quality, Rules for Open Burning, chapter 340, division 264, rule 0010 (short form: OAR 340-264-0010). Available online at: http://www.deq.state.or.us/aq/burning/openburning/openburn.asp (verified 30 April, 2013).
  • Oxford Dictionaries 2013. [Online]. Copyright © 2013 Oxford University Press. Available at: http://oxforddictionaries.com/definition/english/scission (verified 30 April, 2013).
  • Posada, J. A.; Naranjo, J. M.; Lopez, J. A.; Higuita, J. C.; Cardona, C. A. 2011. Design and analysis of poly-3-hydroxybutyrate production processes from crude glycerol. Process Biochem. (Amsterdam, Neth.) 46 (1), 310-317. Availale online at: http://dx.doi.org/10.1016/j.procbio.2010.09.003 (verified 30 April, 2013).
  • Reis M, Albuquerque M, Villano M, Majone M (2011) 6.51 - Mixed Culture Processes for Polyhydroxyalkanoate Production from Agro-Industrial Surplus/Wastes as Feedstocks. In Comprehensive Biotechnology (Second Edition), Editor-in-Chief: Murray M-Y (ed), pp 669-683. Burlington: Academic Press.
  • Schnabel, W. 1992. Polymer Degradation. Hanser Publishers, Munich, Germany, pg. 1.
  • Schonbeck, M.W. and G.K. Evanylo. 1998. Effects of mulches on soil properties and tomato production: I. Soil temperature, soil moisture and marketable yield. Journal of Sustainable Agriculture 13:55–81. Available online at: http://www.tandfonline.com/doi/abs/10.1300/J064v13n01_06#preview (verified 30 April, 2013).
  • Shogren, R.L. and Hochmuth, R.C., 2004. Field evaluation of watermelon grown on paper-polymerized vegetable oil mulches. HortScience 39:1588-1591. Available online at: http://naldc.nal.usda.gov/download/15134/PDF (verified 30 April,, 2013).
  • Smith, B. R., L. C. Wadsworth, M. G. Kamath, A. Wszelaki & C. E. Sams. 2008. Development of Next Generation Biodegradable Mulch Nonwovens to Replace Polyethylene Plastic. In International Conference on Sustainable Textiles (ICST 08). Wuxi, China (CD ROM).
  • Sullivan, D. 2011. Compostable plastics and organic farming. BioCycle (3), 36-41. Available online at: http://www.biocycle.net/2011/03/compostable-plastics-and-organic-farming/ (verified 30 April, 2013).
  • Tachibana, Y., T. Maeda, O. Ito, Y. Maeda & M. Kunioka. 2009. Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid)/Ecoflex®/Modified Starch in Mandarin Orange Groves. International Journal of Molecular Sciences 10, 3599-3615. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2758133/ (verified 30 April, 2013).
  • United States Department of Agriculture Federal Biobased Products Preferred Procurement Program (FB4P). 2007. What are bio-based products? [Online]. Available at: http://www.dm.usda.gov/procurement/programs/biobased/awarenessbrochure_m... (verified 30 April, 2012).
  • Wadsworth, L. C., A. Wszelaki, D. G. Hayes & B. R. Smith. 2009. Development of Enhanced Biodegradable Mulch Nonwovens to Replace Plastic Films. AATCC International Conference, Myrtle Beach, SC, March 10-12, 2009.
  • Wadsworth, L. C., Hayes, D. G., Wszelaki, A. L., Washington, T. L., Martin, J., Lee, J., Raley, R., Pannell, C. T., Dharmalingam, S., Miles, C., Saxton, A., and Inglis, D. A. 201x. Evaluation of degradable spun-melt 100% polylactic acid nonwovens mulch materials in a greenhouse environment. Journal of Engineered Fibers and Fabrics (accepted Sep 20, 2012).

 

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8260

Cleaning and Disinfecting in Organic Poultry Production

lun, 2013/04/29 - 13:50

eOrganic author:

Dr. Jacquie Jacob Ph.D., University of Kentucky

NOTE: Brand names appearing in this article are examples only. No endorsement is intended, nor is criticism implied of similar products not mentioned.

NOTE: Before applying ANY product, be sure to 1) read and understand the safety precautions and application restrictions, and 2) make sure that the brand name product is listed in your Organic System Plan and approved by your certifier. For more information see Can I Use this Product for Disease Management on my Organic Farm?

Introduction

A good organic poultry health program begins with a plan for cleaning and disinfecting the equipment and facilities used.

  • Cleaning refers to the removal of organic material from objects.
  • Disinfecting refers to the destruction of microorganisms on objects.
  • Sanitizing refers to the simultaneous cleaning and disinfecting of objects.

The first step is cleaning—removing all the organic material. Most disinfectants are ineffective if they can't get through the organic material to attack the microorganisms, and they will be inactivated in the presence of organic material. Many disinfectants require a certain concentration and contact time in order to be effective. It is important to follow the manufacturer's instructions.

A variety of substances can be used as cleansers, disinfectants and sanitizers for organic poultry production, but it is important to verify with your certifying agent before using any specific product. The products below typically act rapidly to destroy bacteria but break down quickly so that they do not leave an active residue behind.

Acetic acid (Vinegar)

In the U.S., vinegar is 5% acetic acid. Higher concentrations are more effective, but need to be purchased through chemical suppliers and not in the grocery store or pharmacy. A solution of 1% acetic acid can be used to decontaminate the surface of freshly laid eggs.

Status: Allowed
Class: Livestock Feed Ingredients, Livestock Health Care, Livestock Management Tools and Production Aids
Origin: Nonsynthetic Agricultural
Description: Nonsynthetic forms of acetic acid may be used topically and as disinfectants. For use as a disinfectant and sanitizer. Organic sources required for internal use.
NOP Rule: 205.105 & 205.238(c)(1)

Alcohols

Alcohols work by denaturing bacterial proteins but they do not work in the absence of water. It is for this reason that a 70% isopropyl alcohol is more effective than a 99% pure product. Alcohols are effective against a wide range of microorganisms including vegetative bacteria, viruses, and fungi. They do not, however, work against spores. Although they have been shown to inhibit sporulation and spore germination, this effect is reversible. The lack of sporicidal activity makes alcohols ineffective sanitizers, so they are mainly used for cleaning hard surfaces or skin.

Ethanol

Status: Allowed with Restrictions
Class: Livestock Health Care, Livestock Management Tools and Production Aids
Origin: Synthetic
Description: May be used as a disinfectant and sanitizer only. In medical treatments, may be used only as a topical disinfectant.
NOP Rule: 205.603(a)(1)(i) As disinfectants, sanitizer, and medical treatments as applicable. For use as disinfectant and sanitizer.

Isopropanol

Status: Allowed with Restrictions
Class: Livestock Health Care, Livestock Management Tools and Production Aids
Origin: Synthetic Nonagricultural
Description: May only be used as a disinfectant.
NOP Rule: 205.603(a)(1)(ii) Isopropanol. For use as disinfectant only.

Chlorine materials

Chlorine products are effective, cheap and widely available, making them the most common disinfectant. Sodium hypochlorite, commonly known as bleach, is used most frequently. Pure bleach typically must be diluted before being used. Calcium hypochlorite is typically used as a swimming pool additive.

Status: Allowed with Restrictions
Class: Livestock Management Tools and Production Aids
Origin: Synthetic
Description: May be used for disinfecting livestock facilities and equipment. Residual chlorine levels in the water in direct contact with food products shall not exceed the maximum residual disinfectant limit under the Safe Drinking Water Act, currently 4 mg/L (4 ppm) expressed as chlorine. Includes calcium hypochlorite, chlorine dioxide and sodium hypochlorite.
NOP Rule: 205.603(a)(7) As disinfectants, sanitizer, and medical treatments as applicable… Chlorine materials—disinfecting and sanitizing facilities and equipment. Residual chlorine levels in the water shall not exceed the maximum residual disinfectant limit under the Safe Drinking Water Act. See also: (i) Calcium hypochlorite. (ii) Chlorine dioxide. (iii) Sodium hypochlorite.

For more information on the use of chlorine products, refer to the NOP guidance document The use of chlorine materials in organic production and handling.

Calcium hypochlorite

Status: Allowed with Restrictions
Class: Processing Sanitizers and Cleaners
Origin: Synthetic Nonagricultural
Description: May only be used as a disinfectant and sanitizer for food contact surfaces provided it is not used in or on organic food or other organic processed products. Residual chlorine levels in water shall not exceed the Maximum Residual Disinfectant Limit under the Safe Drinking Water Act, currently 4 mg/L (4 ppm) expressed as chlorine.
NOP Rule: 205.605(b)

Chlorine dioxide

Examples of commercial products include CDG Solution 3000® and Oxine®, both of which are OMRI listed.

Status: Allowed with Restrictions
Class: Livestock Management Tools and Production Aids
Origin: Synthetic
Description: May be used for disinfecting livestock facilities and equipment. Residual chlorine levels in the water in direct contact with food products shall not exceed the maximum residual disinfectant limit under the Safe Drinking Water Act, currently 0.8 mg/L (0.8 ppm) expressed as chlorine dioxide.
NOP Rule: 205.603(a)(5)

Sodium hypochlorite (bleach)

Examples of commercial products include Oxcide® (OMRI listed) and Keeper® (meets USDA organic regulations - check with certifying agent before using).

Status: Allowed with Restrictions
Class: Processing Sanitizers and Cleaners
Origin: Synthetic Nonagricultural
Description: May only be used as a disinfectant and sanitizer for food contact surfaces. Residual chlorine levels in water shall not exceed the Maximum Residual Disinfectant Limit under the Safe Drinking Water Act, currently 4 mg/L (4 ppm) expressed as chlorine.
NOP Rule: 205.605(b)

Hydrogen peroxide

Hydrogen peroxide is commonly used in the drinking water. It is considered environmentally friendly because it rapidly breaks down into water and oxygen. Hydrogen peroxide is effective against viruses, bacteria, yeasts, and bacterial spores. Higher concentrations and longer contact times are required to kill spores. Examples of commercial products are PLC™ Poultry Drinking Water System Line Cleaner (OMRI listed) and OxyBlast (meets USDA organic regulations - check with certifying agent before using).

Status: Allowed with Restrictions
Class: Livestock Management Tools and Production Aids
Origin: Synthetic
Description: Also known as hydrogen dioxide.
NOP Rule: As disinfectants, sanitizers, and medical treatments as applicable.

Iodine

An example of a commercial iodine disinfectant is BioSentry® (check with certifying agent before using).

Status: Allowed with Restrictions
Class: Livestock External Parasiticides and Pesticides, Livestock Feed Ingredients, Livestock Health Care, Livestock Management Tools and Production Aids
Origin: Synthetic
Description: Restricted as a feed supplement and for use as a sanitizer and topical disinfectant. Nutrient sources include calcium iodate, calcium idobehenate, cuprous iodide, 3,5-diiodosalicylic acid, potassium iodate, potassium iodide, sodium iodate, sodium iodide, thymol iodide. Sanitizers and topical disinfectant sources include potassium iodide and elemental iodine in phosphoric acid solution.
NOP Rule: 205.603(a)(10), 205.603(b)(2) & 205.603(d)(2) As disinfectants, sanitizers, and medical treatments as applicable. As topical treatment, external parasiticide, or local anesthetic as applicable. As feed additives… Trace minerals, used for enrichment or fortification when FDA approved.

Peroxyacetic/peracetic acid

Peroxyacetic acid kills spores, bacteria, viruses, and fungi. It works by denaturing proteins, including enzymes, and makes cell walls leaky. Peroxyacetic acid also decomposes into safe byproducts (acetic acid and oxygen) and can remain active in the presence of organic matter contamination. Examples of commercial products include SaniDate® 5.0 and Oxivir.

Classification: Livestock Management Tools and Production Aids
Category: Peroxyacetic/Peracetic Acid (CAS #79-21-0)
Restriction: May only be used for disinfecting facility, processing equipment, seed and asexually propagated planting material.

Phosphoric acid

Phosphoric acid is corrosive and may damage equipment. It must be handled with care.

Status: Allowed with Restrictions
Class: Livestock Management Tools and Production Aids
Origin: Synthetic
Description: For use only as an equipment cleaner. Direct contact with organic livestock or land is prohibited.
NOP Rule: 205.603(a)(14) Phosphoric acid—allowed as an equipment cleaner, Provided, That, no direct contact with organically managed livestock or land occurs.

References and Citations
  • Agricultural Marketing Service—National Organic Program [Online]. United States Department of Agriculture. Available at: http://www.ams.usda.gov/nop/ (verified 07 April 2013).
  • National Organic Program. 2011. NOP 5026. Guidance: The use of chlorine materials in organic production and handling [Online]. United States Department of Agriculture–Agricultural Marketing Service. Available at: http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5090760 (verified 07 April 2013).

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 7837

Records Needed for Organic Poultry Certification

lun, 2013/04/29 - 13:12

eOrganic authors:

Devon Patillo, CCOF

Dr. Jacquie Jacob Ph.D., University of Kentucky

Introduction

Organic poultry producers are required to keep records to demonstrate compliance with USDA National Organic Program (NOP) requirements. Depending on the scale of operation and the method by which eggs, meat, or live birds are sold, certain records may be more appropriate than others.

Organic certification requirements allow recordkeeping systems to be adapted to a particular operation. However, all operations must keep records in enough detail to demonstrate to organic inspectors and certifiers that all requirements of the organic regulations are met. Recommended records are described below. Your certifier will determine your compliance with National Organic Program standards. Be prepared to work with your certifier and adjust your recordkeeping system to meet the required standards.

Poultry producers must meet the organic regulations summarized below. To read the full text of the organic regulations, visit The Electronic Code of Federal Regulations (e-CFR).

 

§ 205.103 Recordkeeping by certified operations

Below is the full text of the recordkeeping requirement of the National Organic Program.

(a) A certified operation must maintain records concerning the production, harvesting, and handling of agricultural products that are or that are intended to be sold, labeled, or represented as “100 percent organic,” “organic,” or “made with organic (specified ingredients or food group(s)).”

(b) Such records must:

(1) Be adapted to the particular business that the certified operation is conducting;

(2) Fully disclose all activities and transactions of the certified operation in sufficient detail as to be readily understood and audited;

(3) Be maintained for not less than 5 years beyond their creation; and

(4) Be sufficient to demonstrate compliance with the Act and the regulations in this part.

(c) The certified operation must make such records available for inspection and copying during normal business hours by authorized representatives of the Secretary, the applicable State program's governing State official, and the certifying agent.

 

§ 205.236: Animal Origin

Section 205.236(c) requires that, “the producer of an organic livestock operation must maintain records sufficient to preserve the identity of all organically managed animals and edible and non-edible animal products produced on the operation.”

  • Animal purchase records
    Birds must be managed organically starting no later than the second day of life.  Keep records to show: date(s) of purchase, number of birds purchased, and the age of animals at time of purchase.
  • Mortality and cull records
    These records ensure that non-organic birds are not added to your flock. Document observed deaths and intentional culls. Bird deaths and culls subtracted from the number of purchased birds need to correspond to the number of birds being certified. Your certifier may use this information to list the number of birds on your certificate and to ensure that non-organic birds have not been added to your flock. (Purchases – Mortality & Culls = Size of current flock)

This means that all organic poultry must be grouped in flocks or otherwise identified, with corresponding records maintained of all feeds and feed supplements purchased and consumed for all stages of life; all health events and medications or activities; housing and pasture rotations; etc. Records must also be maintained of all products produced, including meat and eggs, or feathers for organic fishing flies.

§ 205.237: Feed
  • Feed Production or Purchase Records
    All feed provided must be certified organic. Feed production and/or purchase records need to demonstrate that all feed provided was certified organic. Keep copies of all purchase documentation. Ensure that the total number of pounds purchased is easy to determine. Feed and feed supplement records should include type of feed purchased, quantity purchased, dates purchased, source, and agency that certified the feed as organic. If mixing your own feed, you need to document the same information for each feed ingredient used. You need to list all supplements, including vitamins, amino acids, minerals, etc. used and the reason they were used.
  • Feed labels, ingredient statements, and certification information
    Keep documentation to demonstrate that the feed you purchased was in fact organic. Keep retail labels that include a “Certified Organic by [certifier’s name]” statement. These will appear under the manufacturer’s name on the retail label. If purchasing bulk feed without a retail label, you will need to obtain a list of ingredients in the feed formula and a copy of the manufacturer’s organic certificate, in addition to the purchase invoice and delivery ticket.
  • Feed supplement and additive purchases
    Only approved feed supplements and additives are allowed. Seek approval of feed supplements prior to use. Once approved, keep documentation of your purchases. Ensure the purchase records include the name of the product(s) purchased, quantity purchased, and date.  
§ 205.238: Health care and treatment
  • Health care product purchases (medicines, vaccines, drugs)
    Only approved health care materials are allowed. Seek approval of any health care materials prior to use. Once approved, keep documentation of your purchases. Ensure the purchase records include the name of the product(s) purchased, quantity purchased, and date.
  • Mortality/cull records
    These records provide an indication of the health of your birds. Document observed deaths and intentional culls. If documented on a calendar, be sure to transfer the information from your calendar to a single location before your inspection so it will be easier to see trends or patterns.

An example of a poultry health record form is available from ATTRA .

A preventive health care program should include control of possible disease vectors including rodents, insects (e.g., external parasites, flies and darkling beetles), and internal parasites. The methods of control should be outlined with a record of monitoring and action(s) taken. Predator control measures should also be documented.

A preventive health care program also includes keeping equipment used clean as well as cleaning and disinfecting between flocks. A record must be kept of all sanitation and cleaning products used and when. Use of any vaccines must be recorded with the date used and source of the vaccine.

Any physical alterations used such as beak trimming, de-snooding, toe trimming, and wing trimming must be recorded with explanation of when performed and why.

As part of your biosecurity program you should limit visitors to your farm. If there are visitors, you should document who and when, and where they had been prior to the visit.

§ 205.239: Living conditions
  • General information
    Certifiers may require specific data about living conditions provided to birds. It is a good idea to have the following information available for your certifier. It is recommended to note the following information on a drawing of any coops or houses:
    • Perch space (inches per bird)
    • Stocking density: Space per bird indoors (square feet per bird)
    • Stocking density: Space per bird outdoors (square feet per bird)
    • Number of birds per nest box (birds per nest box)

Organic poultry are required to have outdoor access depending on their stage of life. The outdoor access area must also be maintained as organic and records kept to document that it has been. This includes a history of how the fields have been used. Section 205.203 requires that all organic producers must take steps to prevent the contamination of water and minimize soil erosion. Soil and water tests should be done to monitor quality. For pastures this will also include the type and source of seeds used. It is also important to document at which age chicks are first given access to the outdoors.

§ 205.105: Other substances
  • Cleaning/Disinfecting records
    Only approved sanitizers are allowed when cleaning houses or facilities between flocks. Some sanitizers must be rinsed, while others do not require a rinse. Work with your certifier to determine sanitizers that are allowed. Document cleaning of houses and include date, sanitizer(s) used, and any other information required by your certifier.
Additional Documentation

As with any commercial operation, the number of eggs or birds produced should be recorded. This documentation is required for organic certification, but also gives the producer an idea of the level of production and early detection of any sudden drops. Daily feed consumption and water intake should also be monitored.

If non-organic products are being raised on the same farm, there must be documentation showing how the commingling of organic and non-organic products is prevented.

The type and amount of bedding material used (e.g., pine shavings) needs to be documented. If bedding materials are consumed by the birds, then the bedding materials must be organic, and records must be maintained to verify organic status.

Manure management is an important part of an integrated farming operation. Manure is a valuable byproduct of poultry production operations and a good source of nutrients for organic crop production. The amount of manure produced, and how it is used, needs to be documented.

Whether you are producing poultry meat or eggs, the products must be handled organically while being shipped for processing. For meat birds, this includes the certification of the facility where the birds are slaughtered, as well as the method and condition of transport to the slaughter facility. The slaughter facility must be certified organic, and its current certificate and documentation must be kept in your records. Similarly, if there is off-farm egg processing, the facility must be certified organic or covered under your certificate in order for the eggs to be labeled as such. If you are processing and packaging the eggs on-farm, the egg handling area and any materials used must be included in the overall organic plan for the farm.

Adapt your recordkeeping system to your own operation

Different producers may need to keep different types of records to demonstrate compliance because of their activities or scale. While certain records are essential for most operations—such as feed purchase records—certifiers may require other records for some producers and not others if they feel that additional information is required to determine compliance with the regulations. In general, larger operations are required to keep more records than smaller operations. Again, your certifier will determine your compliance with National Organic Program standards. Be prepared to work with your certifier and adjust your recordkeeping system to meet the recordkeeping standards.

The records you are required to keep may also depend on how you market your eggs, live organic birds, or meat. If you sell on a wholesale basis to a single buyer, a summary of sales or transportation of birds may be adequate. Total income will also need to be reported. Certifiers rely on this information to ensure that non-organic product is not being sold as organic.

Producers marketing directly to consumers or to a variety of accounts are also required to document total sales. Sales information must include both the quantity of product sold and income from sales. Certifiers rely on this information to ensure that non-organic product is not being sold as organic.

You are required to make your records available during normal business hours to your certifier, state organic program (California only), and authorized representatives of the USDA. You are also required to keep your records on file for no less than five years.

How records might vary for large vesus small producers Large producers
  • Outdoor Access Logs
    Identify dates and reason(s) for confinement. Be specific. Most certifiers will require that you record animals' outdoor access on a daily basis. Additionally, a stated policy or standard operating procedure should describe any time periods when birds are typically confined, including the reason for such confinement (e.g. pullets until feathered).
  • Facility records
    • Diagram of each house
    • Length and width of building
    • Location and size of all doors
    • Outdoor access areas, to scale
    • Locations of feeders/waterers (indoors and outdoors)
    • Temperature logs
    • Cleaning/disinfection of houses between flocks
    • Ammonia levels
Small producers (all birds outside more often than not)
  • Outdoor Access Logs
    Document dates and reason(s) for confinement. Marking days on calendar, with the reason for confinement noted, will most likely be adequate to demonstrate compliance.
  • Bird movement or location records (optional)
    Small producers that move birds around pasture may wish to record the days when birds are moved. This can provide assurances to certifiers that the ground on which birds trod does not become contaminated by excess manure.
References and Citations

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 7778

Organic Poultry Production Systems

mar, 2013/04/23 - 18:10

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic T1206

Organic Soil Fertility

jeu, 2013/04/18 - 11:01

eOrganic authors:

Michelle Wander, University of Illinois

Nick Andrews, Oregon State University

John McQueen, Oregon State University

This article provides an overview of key concepts in organic fertility management, a review of essential macro and micronutrients, and a listing of nutrient amendments approved for use in organic farming systems. It summarizes strategies used to build and manage fertility on organic farms and provides tips on soil testing and use of nutrient budgets.

Introduction: Soils as the Foundation of Organic Farming

Soil health is the foundation of organic farming systems. Fertile soil provides essential nutrients to plants, while supporting a diverse and active biotic community that helps the soil resist environmental degradation. Organic producers face unique challenges in managing soil productivity. Current guidelines on nutrient management for organic farmers are fairly general in nature. Organic farmers rely on intuition and observation, advice from vendors, conventional soil tests, and their own experience to make decisions about the quantity and types of soil amendments to apply. As a result, there is tremendous variability in both the quantities of nutrients applied and the resulting soil fertility status on organically managed farms. Organic farmers seek to "build the soil" or enhance its inherent fertility by using crop rotations, animal and green manures, and cover crops. Crop rotation and tillage practices must provide an appropriate seedbed and pest control while minimizing erosion. Nutrient stocks are maintained through use of natural (non-synthetic) substances and approved synthetic substances listed on the National List of Allowed and Prohibited Substances. This list includes a few approved synthetic fertility inputs, such as elemental sulfur, aquatic plant extracts, liquid fish products, potassium chloride, and sodium nitrate. Many substances on the National List have restrictions, or annotations, on their use, source, or rate of application. Organic farmers are advised to check with their certifying agent before purchasing or applying any synthetic inputs. See Can I Use this Input on My Organic Farm? for more information. In addition, organic growers must document their soil management practices in their organic farming system plan as part of their certification, and keep records of all inputs purchased and applied.

Although the following sections address nutrient management and soil building practices separately, these two apects of management are intimately connected through a system of management. Organic farms that achieve their goals maintain soils and protect the environment while using modest amounts of inputs. Soil tests and simple budgeting tools can help producers maintain balance to achieve success.

Supplying and Managing Nutrients

Although crop nutritional requirements are the same for organic and conventional farms, organic producers apply natural materials and emphasize practices that retain and recycle nutrients within the soil. Sixteen elements are consistently found to be necessary for plants to complete their life cycles (Tables 1 and 2). Additional elements (Table 3) are listed as essential for some species and for animals relying on plants for their nutrition. Carbon, hydrogen, and oxygen--which account for about 95% of plant biomass--are supplied from carbon dioxide and water. The other macronutrients with concentrations greater than 500 micrograms/g plant include nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium (Table 1). Micronutrients taken up in lower abundance are no less neccessary but are not limiting to growth in most situations. Sandy soils with inherently low nutrient contents are an exception. Micronutrients include iron, zinc, manganese, copper, boron, chlorine, and molybdenum.

Table 1. Macronutrients essential for plant growth.

Element Cationic Anionic Other Nitrogen NH4+ NO2-, NO3- organic Phosphorus - HPO4-2, H2PO3-, polyphosphates organic Potassium K+ - - Calcium Ca+2 - - Magnesium Mg+2 - - Sulfur - SO4-2, S2-2 organic

Table 2. Micronutrients essential for plant growth.

Element Cationic Anionic Other Iron Fe, Fe+2, Fe+2 - organic-chelated Manganese Mn, Mn+2 - organic-chelated Copper Cu, Cu+2 - organic-chelated Zinc Zn, Zn+2 - organic-chelated Molybdenum - Mo, MoO4- - Boron - Bo, B(OH)4-, H3BO3 H3BO3 Chlorine - Cl- - Nickel Ni, Ni+ - -

Table 3. Micronutrients essential to support animal health.

Element Cationic Anionic Other Cobalt Co+2 - - Selenium - SeO4-2, SeO3-2, Se-2 organic Sodium Na+ - - Silicon - SiO2-2 -

Organic farmers use natural materials or, when possible, exploit biological processes to supply needed nutrients to soils. Organic fertilizers are needed in larger quantities than are conventional fertilizers because nutrient concentrations tend to be lower. Organic fertilizers can be more expensive, more bulky and less uniform than conventional counterparts. Before applying anything to your field, you should know what the nutrient analysis of the material is, and be certain the substance is allowed by your certifier. See Can I Use this Input on My Organic Farm? for more information.

Table 4. Some of the most commonly used NOP-approved amendments are summarized below. Nutrient contents are listed as proportion of N:P2O5:K2O.

Fertilizer Type Description Comments/Issues Alfalfa meal or pellets Contain around 3 percent nitrogen and are commonly used as an animal feed. Commonly used for high-value horticultural crops but rather expensive for field crops. Ash Wood ash (0–1–3) contains P and K, is a good source for micronutrients and acts as a liming agent. Commonly used in gardens; avoid over-application which can cause alkalinity and salt build up; avoid ash from treated wood or from the burning of manure. Biological amendments While not fertilizers per se, there are a number of biological amendments used to promote biological activity or microbial associations between plants and soils with the intent of increasing plant nutrient uptake. A separate article covering this is under development. Bone meal Typically a mixture of crushed and ground bone that is high in phosphorus. N contents vary depending upon handling. Range from 4:12:1; 1:13:0; 3:20:0.5. Permitted as a soil amendment but can not be fed to animals in certified production. Blood, bone and meat meal are prohibited in many countries in Europe and Japan because of BSE transmission risk. Blood meal Dried blood, is a soluble source of nitrogen. Typical N:P:K contents are 13:1:0. Solubility can vary. Should be used carefully, release of ammonia can burn plants and lead to loss through volatilization. Use limitations are the same as bone meal above. Recently Canada, with the support of IFOAM, proposed to prohibit cattle wastes as fertilizer at the UN Codex Alimentarius session in Montreal, 2004. Allowed under National Organic Program (NOP) regulation. Calcium sulfate (Gypsum) CaSO4.2H2O. Contains about 23% Ca, is a mined deposit that is used to reclaim alkali soils, lower soil pH, and adjust cation balance. Good source for sulfur; useful for alkaline soils with high sodium content. Avoid gypsum from recycled sheetrock. Cocoa Shells Cocoa shells (1:1:3) are available in some regions. They are used as a source of potassium and are popular due to their slow release properties. Also used as a mulch. Dolomitic lime (Calcium-magnesium carbonate) CaCO3–MgCO3 is about 24% Ca and 20% Mg, is a very effective lime source. Over application is perceived to be a problem in horticultural systems. Under application is an issue in some field crop systems. Has a lime equivalent of 1900 lb/ton. Labs following the cation balance theory avoid the use of dolomitic limes, KCl, and oxide forms of trace elements. Feather meal (13:0:0) a by-product of the poultry processing industry, which contains 15% N as non-soluble keratin has been promoted as a slow release N source. Feather meal can transmit the Avian flu, A(H5N1) virus, which is relatively easily transmissible to animals and people. Fish emulsion (Ranges in content from 4:1:1 to 9:3:0); suitable for foliar feeding of starts and the spot treatment of transplants; is reputed to prevent stress, stimulate root growth and provide cold protection. Fish emulsion may be fortified with chemical fertilizer, so be suspicious of any product with a phosphorus content in excess of 4%. Fish products may also contain synthetic preservatives, stabilizers and other products prohibited under the NOP. Fish meal can also contain high levels of PCB’s. Granite Dust Granite dust is available in some regions. It is used as a source of potassium that is popular due to its slow release properties. Availability varies regionally. Greensand (Glauconite) A mined sandstone deposit (typically 0:0:3 or 0:0:6) used as a source of potassium. Also contains iron, magnesium, silica and other trace minerals. Is a common ingredient in potting mixes. High calcium lime (Calcium carbonate) Limestone containing 0–5% magnesium carbonate. Rapid reacting due to high solubility, valued source of Ca and liming where magnesium abundance is a concern and soil is not alkaline. Hydrated lime High quality Ca(OH)2 is a dry powder produced by reacting quicklime with a sufficient amount of water to satisfy the quicklime's natural affinity for moisture. The National Organic Standards Board approved use of calcium hydroxide as a component of Bordeaux mix and lime sulfur for fungicide use, but does not allow its use as a soil amendment. Manures and composts Nutrient contents vary widely, it is recommended they be applied on the basis of phosphorus need. Use as an N source leads to over application of P. Manure- and compost-based P has high plant availability, ranging 70–100% available. Compost, if produced according to NOP requirements, can be applied any time during the growing season. Animal manure can only be used on crops for human consumption if it is incorporated into the soil at least 120 days prior to harvest for crops that contasct the soil or 90 days prior to harvest for crops that do not contact the soil. Potassium Sulfate K2SO4 is a mined fertilizer not widely available. It has been used as a food preservative. This is allowed under the NOP rules if you can prove you are using a mined source that has not been treated with acid or any other chemical reaction to make the potassium more available. This is a good choice for high Mg soils, but it is fairly reactive and must be used carefully. Rock phosphates Rock phosphates are frequently divided into hard rock and colloidal or soft rock forms. Rock phosphate typically has lower availability than colloidal P, which is low (2%) compared to materials like bone meal (11%). Marine sediments are typically ground and cleaned. Availability is low where soil pH is above 6 and biological activity is low. Addition of manures can increase solubility. Contains Calcium and acts as a liming agent. Phosphate rock is most effective at supplying P in soils with low pH (less than 5.5) and low calcium concentrations. Phosphate rock applications made to soils with pH greater than 5.5 may not be effective because of reduced solubility. Sea weed and Kelp (Ranges from 1:0.2:2 to 1.5:0.5:2.5) Also high in micronutrients, Fe, Cu, Zn, Mo, Bo, Mn, Co. and Alginic acid (26%). Is used as a soil conditioner. Several kinds of sea weed and kelp are on the market. Kelp meal can be applied directly to the soil or in starter fertilizer. Can be high in salts and metals. Other reputed benefits are hormones or hormonal activity. Claims to protect plants from stress:  cold, drought and insect pressure. Expensive, so best suited for high value crops. Seed meal (Ranges from 6:1.5:2 to 6:2:2); cotton seed and soybean seed meal have been popular. Now that generically modified crops are so wide-spread sourcing GM free meal can be difficult. Check with your certifier about the needed documentation. Sodium nitrate (16:0:0) Historically an important component of fertilizers, and a raw material for the manufacture of saltpeter. It is a mined product that is about 16–20 percent nitrogen and highly reactive. It acts more like a synthetic fertilizer and can cause sodium buildup in the soil. Can contain medium to high levels of Boron. The NOP stipulates that the nitrogen obtained from sodium nitrate must account for no more than 20 percent of the crop’s total nitrogen requirement. This can be used cautiously when rapidly available nitrogen is needed. It is prohibited by the Farm Verified Organic and Organic Crop Improvement Association-International Federation of the Organic Agriculture Movements accredited levels of certification. European organic standards consider it to be the equivalent of a synthetic fertilizer because it is highly soluble and leaches readily from the soil. Check with your certifier before using. Soybean meal (8:0.7:2) Useful to augment N and P. Often used as a feed additive; medium N release rate; may inhibit germination of small seeds. Check with your certifier before using, due to widespread use of GM soybeans. Sulfate of potash (sul-po-mag and K mag or langbeinite) (0:0:21 with 11 Mg) Naturally occurring crystalline product commonly used to supply potassium. This and calcium sulfate are allowed under the NOP if you can prove you are using a mined source that has not been treated with acid or any other chemical reaction to make the potassium more available. Potassium sulfate is the better choice for high Mg soils, but it is fairly reactive and must be used carefully.

One of the simplest things a producer can do is maintain optimal soil pH levels. This is critical as pH influences nutrient solubility, microbial activity, and root growth. High pH favors weathering of minerals and increases the release of cations but reduces the solubilty of salts including carbonates and phosphates. Lower pH values favor fungi while high pH favors bacteria. Soil pH can also affect the plant’s ability to take up nutrients directly. At very low pH values (<3), cell membranes are impaIred and become leaky. For most crops, soil pH levels are optimal between 6.0 and 7.0. Lime can be applied to raise the pH of acidic soils (pH <6) and supply calcium. Alkalinity, which is more difficult to correct, typically requires the use of sulfur; this remedy is typically temporary and more expensive than liming. When adjusting the pH, it is important to know the crop’s pH requirement since optimum pH levels vary by crop.

Nitrogen (N) is abundant in the environment yet remains the most frequently limiting nutrient for crop production. Organic farms frequently acquire N through nitrogen fixation by legumes. Legume cover crops, green manures, and legume sods can be an excellent sources of N. Vigorous stands of alfalfa, red clover, crimson clover, or hairy vetch can provide between 100-200 lbs N, which should be most, if not all, of the needed N for the subsequent crop. About half the N in a green manure is released during decomposition following incorporation. Nitrogen needs are often supplemented by the addition of animal manures, either composted or raw, or other more concentrated sources of nitrogen. These include blood meal, fish emulsion, fish protein, kelp and seaweed, and vegetable meals. Mined nitrates, such as sodium nitrate (NaNO3, bulldog soda, or Chilean nitrate) may be used, but are limited to a maximum of 20 percent of the crop’s total N requirement. Certifiers frown on use of imported N sources because these share the problems of conventional N sources. Ideally, organic systems will rely on rotations that supply most, if not all, of their N needs.

Phosphorus (P) is another macronutrient that is frequently limiting in sandy soils and/or where systems do not receive additions of animal wastes. Soil P is found in organic and in inorganic forms that are slowly available. Phosphorus availability is sensitive to soil pH and organic matter decay rates. Important sources of P include manure, bone meal, fish and poultry meal, and rock phosphate. High levels of phosphorus are a risk associated with use of manures and some composts.

Potassium (K) is taken up from soil solution and is abundant in soils rich in illitic clays. Mineral weathering can be an important source of K in some soils. Potassium is weakly held on the exchange and so can be depleted where leaching rates are high. Manure and plant meals are good sources for K.

Common sources for nutrients are:

  • Potassium: manure, alfalfa meal, kelp meal, greensand, wood ash, potassium sulfate, and granite dust.
  • Sulfur: acid rain, manures.
  • Calcium: lime, colloidal phosphate, bone meal, gypsum, and wood ashes.
  • Magnesium: dolomitic lime and langeinite.
  • Micronutrients: mineral weathering, manure, compost, and liming amendments. The National Organic Program requires that micronutrients not be used as defoliants, herbicides, or dessicants. Micronutrients made from nitrates or chlorides are prohibited. Soil deficiencies must be documented by soil or tissue testing.
Methods Used to Build Soils Bare fallow

Bare fallow can be used with fallow periods occurring between harvested crops. Fallows commonly occur over the winter in temperate zones or during the dry season in Mediterranean or tropical zones. Use of bare fallow to accumulate water and, at times to control weeds only works to enhance the soil where it concentrates resources enough to increase overall crop productivity. If bare fallow is used, soil erosion must be prevented.

Crop Rotation

Crop rotation varies plant species in time and space and is an important strategy for organic farmers. Goals are to keep the soil surface covered with a growing crop for most of the year. Key elements of rotations include the breaking of disease and pest cycles and the inclusion of soil building cover crops or cropped fallow periods. By selecting effective cover crops or perennial crops farmers can maintain or increase soil organic matter content and nutrient availability during periods when cash crops are not grown. For most organic farmers, fertility is based on the rotation and not the amendment.

Cover Crops

Cover crops include annual, biennial, or perennial herbaceous plants grown in pure or mixed stands. Annual covers occupy the rotation for part of the year. Perennial crops may be referred to as ley or pasture phase or as a plant-fallow. Cover crops provide soil cover and can help loosen compacted soil through the growth of roots. They enhance soil physical condition and improved water filtration. Legume cover crops provide nitrogen while non-legumes can increase nutrient availability to subsequent crops by taking up nitrogen, phosphorus, and potassium that might otherwise leach or become unavailable to plants.

Diversification

Diversification through rotation and use of covers or ley crops can reduce crop insect pests and diseases, if the cover crops are not alternate hosts. Both covers and perennial ley covers help maintain or increase soil organic matter if they are allowed to grow long enough to produce sufficient biomass. These also help prevent soil erosion caused by both water and wind, and suppress weeds. The management of residues within rotations can be quite sophisticated. For a good example, see the video of a living mulch system for soil fertility featuring Helen Atthowe of BioDesign Farm.

Helen Atthowe of BioDesign Farm describes using a living mulch to achieve slow release fertility
Video 1. Helen Atthowe of BioDesign Farm describes using a living mulch to achieve slow release fertility. Video credit: Alex Stone, Oregon State University, Weed Em and Reap Part 2 Living Mulch System Soil Fertility video.

For more information on rotation and cover crops, see the ATTRA publication Overview of Cover Crops and Green Manures and the SARE publication Managing Cover Crops Profitably.

Judicious Use of Tillage

Tillage is an integral part of many organic systems. Management of soil tilth, organic matter, and fertility is an important aspect of a successful organic farming system. Current organic systems usually require tillage prior to planting and cultivation after planting, especially for corn and soybean production, to control weeds and reduce the incidence of seedling diseases and insect pests. However, tillage destroys the organic matter that is critical in improving soil fertility and soil water-holding capacity. Tillage should be performed when soil moisture is low enough to prevent compaction. Since primary tillage operations are usually performed at least a month before a crop is planted, this requires careful planning and the ability to take advantage of periods of dry weather. No-till agriculture in organic systems is starting to be used in parts of the country. The Rodale Institute has experimented with no-till organic farming using cover crops and tractor-mounted rollers to kill the cover just before planting into it. Ron Morse at Virginia Tech and Nancy Creamer at North Carolina State University have been adapting these systems for organic vegetable production. Watch Weed Em and Reap Part 2 for more information.

Organic Amendments

Organic amendments can be an important resource. Soil fertility and physical condition can be effectively maintained with rotation and appropriate use of organic amendments. Application should be made based on soil testing and/or use of budgets. Manures and composts are the most common organic resources where livestock is in the vicinity. Estimating nutrient contents and availability is necessary for organic materials. For a farmer's perspective on using organic amendments, watch the video of Steve Pincus of Tipi Produce.

Steve Pincus of Tipi Produce in Wisconsin explains how fertility is not a matter of NPK

Video 2. Steve Pincus of Tipi Produce in Wisconsin explains how fertility is not a matter of NPK and how bulky organic matter is managed to improve tilth and maintain nutrient supply on his farm. Video credit: John Marlin, Agroecology and Sustainable Agriculture Program, University of Illinois.

Problems Associated with Nutrient Over-Addition

There is such a thing as too much of a good thing. Off-site problems caused by over-application of nutrients are better recognized than are problems caused on-site. Conventional agriculture is the primary source of non-point source and P pollution that contribute to a myriad of environmental and health risks. Problems of over-application in organic systems vary; probably P over-additions are most widespread where manure is readily accessible. This is because the ratio of P to N in manure exceeds that required by the plant. Avoid over-reliance on animal manures, in addition to accumulation of excess phosphorus, concentrations of copper, and zinc, which may accumulate in soils. Over-addition of N, particularly in readily available forms, is a common problem. Over-addition of N and P in organic systems can occur in situations where leaching is restricted (eg., in greenhouses) or after N rich cover crops or manures are applied. The notion that N surplus promotes microbial activity and works against organic matter storage and suppresses plant-microbe associations is finally being accepted as an additional downside of over-fertilization. Excess nutrients can also increase plant susceptibility to pathogens and arthropod pests and can also lead to increased weed competition. Tendency toward nutrient leaching and ability to hold and retain nutrients varies with soils and climatic conditions. Texture and CEC are related to this, with nutrient storage capacity increasing with soil clay and silt contents and cation exchange capacities.

Soil Tests and Nutrient Budgeting

To manage nutrients effectively you can use soil testing and nutrient budgeting. Soil tests are used by organic farmers for several reasons:

  1. to ensure that pH and nutrient levels and proportions are in appropriate ranges;
  2. to justify the application of micronutrients and other approved fertilizers to a certifier, or to comply with other certification requirements;
  3. to identify soil nutrients in excess, so soil and fertility management strategies can be manipulated to a) reduce levels of excess nutrients over time, or b) mitigate the impacts of the excess nutrients on crop, soil, and environmental quality; and/or
  4. to track trends in nutrient content, pH, and soil organic matter content over time to ensure soil improvement is taking place.

The National Organic Program regulations require that micronutrients and other fertilizers be applied only when soil or tissue tests indicate a deficiency. Because of this language, some certifiers may require soil testing and possibly other tests. Contact your certifier for its testing requirements. See the related article, Organic Certification of Vegetable Operations.

Frequency of soil testing will depend on your purpose in testing and your situation. To track trends in macronutrients, pH and soil organic matter content, testing once every two or three years, or at a specific point in your rotation cycle, may be sufficient. However, if you are just starting to manage your soil’s fertility with organic practices, or adopting new soil or nutrient management practices, you might want to test more frequently.

Timing of testing will also depend on the purpose of the test. To determine nutrient status of your soil for the upcoming season, test your soil in early spring. To test contents of nutrients with potential to leach over the winter, test in late summer.

A typical soil test evaluates your soil’s pH, CEC, and content and proportion of macronutrients—calcium, magnesium, potassium, phosphorus, and sulfur—which are required by plants in relatively large quantities. Soil organic matter content may not be a routine test, but can be requested. Soils can also be tested for micronutrients (nutrients required by plants at relatively small quantities).

Soil testing laboratories use different soil testing methods that may generate different results. It is important to understand the methods used to generate your test results and use interpretation information that corresponds to that testing method. In addition, using the same testing laboratory for all your testing over time will allow you to compare your test results from year to year and track trends. A soil test is only as good as the soil sample it evaluated. It is important to take a representative sample of the field and the soil volume the crop plant roots will explore to obtain nutrients.

References and Citations Further Reading
  • Agricultural Marketing Service—National Organic Program [Online]. United States Department of Agriculture. Available at: http://www.ams.usda.gov/nop/ (verified 10 March 2010).

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 1471

Using Cover Crops in Organic Systems: Resources and Research from SARE

lun, 2013/04/15 - 12:17

The Sustainable Agriculture Research and Education (SARE) program has funded hundreds of research and education projects related to cover crops since 1988. SARE’s Cover Crop Topic Room features free information products (books, bulletins, webinars, etc.) and research projects relevant to both conventional and organic production.

Resources

NOTE: Some of the linked resources may also discuss non-organic production methods. Before applying any product, be sure to 1) read and understand the safety precautions and application restrictions, and 2) make sure that the brand name product is listed your Organic System Plan and approved by your organic certifier. For more information see Can I Use this Product for Disease Management on my Organic Farm?

Cover Crops and No-Till Management for Organic Systems
This Rodale Institute fact sheet reviews the use of cover crops and no-till in organic systems including selection, establishment, and mechanical termination of cover crops; crop rotations; and energy and production budgets.

Organic Fertilizer and Cover Crop Calculator
This free, online tool developed by Oregon State University compares the nutrient value and cost of cover crops, organic and synthetic fertilizers, and compost. It can be used to develop well-balanced and cost-effective nutrient management programs. It is most appropriate for farmers in western Washington and western Oregon.

Cover Crops for All Seasons—Expanding the cover crop tool box for organic vegetable producers
This Virginia Association for Biological Farming information sheet, authored by Mark Schonbeck and Ron Morse, provides research-based information on a cover crop “toolbox” from which organic vegetable growers can select cover crops most suited to their regions and production systems.

Crop Rotation on Organic Farms: A Planning Manual
This 154-page book, free to download, reviews how farmers are using crop rotations to improve soil quality and health, and manage pests, diseases, and weeds. Consulting with expert organic farmers, the authors share rotation strategies that can be applied under various field conditions and with a wide range of crops. Crop Rotation on Organic Farms is most applicable for the northeastern United States and eastern Canada, but may also be useful for other regions of the United States.

Managing Cover Crops Profitably
This 244-page book, free to download, explores how and why cover crops work and provides all the information needed to build cover crops into any farming operation—both conventional and organic. Managing Cover Crops Profitably includes detailed management information on the most commonly used species. For Midwestern farmers: The information in Managing Cover Crops Profitably formed the foundation of the Midwest Cover Crops Council's Cover Crop Decision Tools, which are interactive, web-based systems to assist farmers in selecting cover crops to include in field crop and vegetable rotations.

Research

The Cover Crop Topic Room includes a selection of SARE-funded research conducted by farmers, scientists, Extension educators and others on these topics:

Examples of research on cover crops in organic systems include:

To discover more of SARE’s organic cover crop research portfolio, browse the Cover Crop Topic Room or visit SARE's database of projects and conduct full text or advanced keyword searches.

About SARE

The Sustainable Agriculture Research and Education (SARE) ­program’s mission is to advance—to the whole of American agriculture—innovations that improve profitability, stewardship and quality of life by investing in groundbreaking research and education. SARE is supported by the National Institute of Food and Agriculture (NIFA), USDA. For more information, visit www.sare.org.

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8780

About Organic Dairy Producer Profiles

ven, 2013/04/12 - 14:23

eOrganic author:

Lisa McCrory, Northeast Organic Dairy Producers Alliance

Introduction

Organic dairy producer profiles are the stories of real farmers, their journey through their transition to organic, and their practices as certified organic farms today. These articles may provide a holistic view of the farm. Often they capture the decision-making processes that led a farm family to decide to transition to organic. They may also highlight production challenges faced during the process and how they worked through those issues. These stories include new practices that farmers learn and implement through the process. Many of these stories have been documented by the Northeast Organic Dairy Producers Alliance (NODPA). Please note that practices mentioned in these articles may or may not meet the current organic standards as certain national organic program production rules change and/or have changed over time. Be sure to check with your local certifier about current standards. We hope that these farmer's stories can provide knowledge, strength, and positive energy as they share their transition to organic dairying.


Vermont organic dairy farmers, John Clark and Jack Lazor, at field day. Photo credit: Lisa McCrory, Earthwise Farm and Forest

Producer Profiles References and Citations
  • Northeast Organic Dairy Producers Alliance [Online]. Available at: http://www.nodpa.com (verified 17 March 2010).

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

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Scouting for Vegetable and Fruit Pests on Organic Farms

ven, 2013/04/05 - 12:14

Join eOrganic for a webinar on Scouting for Vegetable and Fruit Pests on Organic Farms, by Helen Atthowe and Doug O'Brien. The webinar will take place on Thursday, April 25, 2013 at 2PM Eastern Time (1PM Central, 12PM Mountain, 11AM Pacific Time.) The presentation is free and open to the public, and advance registration is required.

Register now at https://www1.gotomeeting.com/register/172329329

About the Webinar

Crop consultant, Doug O’Brien, and organic farmer, Helen Atthowe, share their pest monitoring and decision making tips and short cuts. Learn how to look for insect, disease, and crop quality problems on organic vegetable and fruit farms. We will also touch on some ideas about how to maintain records that will help you better understand pest problems and what to do about them.

About the Presenters

Helen Atthowe has been farming on her own and consulting for other organic vegetable and fruit farms for 25 years. She was a horticulture extension agent for 15 years and owned and operated Biodesign Farm (30 acre diverse organic fruit and vegetable farm) in western Montana for 17 years. She recently spent 6 months as a consulting vegetable grower for a 2000 acre organic vegetable and fruit farm in northern Colorado with a 5000 member CSA.

Doug O'Brien currently owns and operates Doug O’Brien Agricultural Consulting, providing on-site technical advice, field monitoring, and research for clients involved in fresh produce growing, harvesting, cooling and marketing. He is an adjunct professor at Cabrillo College, in Santa Cruz, CA and teaches classes in organic farming. Previously, Doug was a co-owner of an organic produce brokerage company, a crop production manager, and an assistant farm advisor.

Find all upcoming and archived eOrganic webinars at http://www.extension.org/pages/25242

  System Requirements

PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.6 or newer
Mobile attendees
Required: iPhone®, iPad®, Android™ phone or Android tablet

 

Java needs to be installed and working on your computer to join the webinar. If you have concerns, please test your Java at http://java.com/en/download/testjava.jsp prior to joining the webinar. If you are running Mac OS X 10.6 with Safari, please be sure to test your Java. If it isn't working, please try Firefox (http://www.mozilla.com) or Chrome (http://www.google.com/chrome).


 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8951

Organic Systems Research Webinars in March and April

lun, 2013/03/25 - 13:19

Join eOrganic for three webinars on organic systems research tomorrow and in April. All webinars are free and open to the public, and advance registration is required at the links below.

If you missed any of our recent webinars, you can find all the archived recordings at http://www.extension.org/pages/25242

March 26, 2013: Organic Farming Systems Research at the University of Nebraska, by Elizabeth Sarno, Charles Shapiro, Richard Little, Vicki Schlegel, Jim Brandle. Register at http://www.extension.org/pages/67368

April 18, 2013: Supplementing the Organic Dairy Cow Diet: Results of Molasses and Flaxseed Feeding Trials Webinar, by Kathy Soder, USDA ARS. Register at http://www.extension.org/pages/67505

April 23, 2013: Researcher and Farmer Innovation to Increase Nitrogen Cycling on Organic Farms, by Louise Jackson and Tim Bowles, University of California-Davis. Register at http://www.extension.org/pages/67391

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

eOrganic 8877

Black Cohosh (Actaea racemosa L.)

ven, 2013/03/22 - 15:51
***Please note there is a downloadable version of the fact sheet as a pdf file at the end of the article.***  Black Cohosh  (Actaea racemosa L.) Botanical Information Black cohosh [formerly Cimicifuga racemosa (L.) Nutt] is a member of the Ranunculaceae family. It is a native medicinal plant found in rich hardwood forests from as far north as Maine and Ontario, south to Georgia, and west to Missouri and Indiana. In North Carolina, it can be found at elevations up to 4,000 feet and is most common in the western part of the state. The leaves are large with three pinnately compound divisions and irregularly toothed leaflets. Tall florets of white flowers, on wand-like flower stalks, bloom from May to July, often towering over 6 feet tall. From August to October, seeds develop in capsules that make a rattling sound when shaken. At this stage, the seeds are mature and ready to be harvested.   The black cohosh rhizomes and roots are economically valuable. The rhizome is dark-brown to black in color, is thick and knobby, and produces large buds on the upper surface. The rhizomes are covered with fibrous roots, which are usually concentrated on the bottom portion of the rhizome. Throughout the rest of this article, "root" refers to the rhizome and roots, unless stated otherwise. The root is most commonly harvested when the leaves on the plant start to die back in the fall.    Bioactive Components     The main bioactive components of black cohosh appear to be the triterpene glycosides, including actein and 27-deoxyactein (also known as 23-epi-26-deoxyactein); phenylpropanoid derivatives, the majority of which are caffeic acid derivatives; and flavonoids. Other compounds found in the root include aromatic acids, tannins, resins, and fatty acids.   Uses and Treatments Native Americans used black cohosh for a variety of medical conditions ranging from gynecological problems to snake bites. Physicians made use of it in the 19th century to treat fever, menstrual cramps, and arthritis. In Europe, black cohosh has been used for over 50 years as a treatment for menstrual pain. Other traditional and folk uses include treatment of sore throats and bronchitis. Currently, the primary use of this product is as an alternative to hormone replacement therapy (HRT) for treatment of menopause and premenstrual syndrome. Black cohosh has been clinically proven to create an "estrogen-like" effect in the user, often reducing unpleasant menopausal symptoms, such as hot flashes and night sweats.   Cultivation Practices Site Selection Black cohosh prefers a rich, moist soil high in organic matter. In its natural habitat, it is usually found in shaded or partially shaded areas, although it will grow in full sun. Black cohosh can be grown successfully in raised beds in the woods (referred to as "woods cultivated"), in raised beds under an artificial shade structure (referred to as "shade grown"), or in a low-density, low-input method mimicking how it grows in the wild (referred to as "wild simulated").    Regardless of the cultivation system used, it is important to choose a site with well-drained but moist soil. Black cohosh has been known to tolerate more light and soil variations than ginseng or goldenseal, provided adequate moisture is available. Raised beds are recommended, especially for clay soils or areas that tend to stay wet after a heavy rain. Make sure sufficient compost or other organic material is added to raise the organic matter content of the soil. Soils with pH of 5 to 6 are ideal for growing black cohosh.   For woods-cultivated or wild-simulated production, select a site shaded by tall hardwood trees. Look for a site where other woodland plants grow such as mayapple, trillium, bloodroot, ginseng, or a native stand of black cohosh. If woods are not available, an artificial shade structure can be constructed. Typically, wood lath or polypropylene shade cloth providing 30 to 85 percent shade is used. Build the structure 7 feet tall or higher with two opposite ends open to the prevailing breeze. Black cohosh will grow in an open field in full sun, although the effect on plant growth, root quality, and chemical constituents is not fully understood.     Planting Black cohosh is most easily propagated by dividing the rhizomes in spring or fall. Plants can also be started indoors from seed or seed can be directly sown into the ground, but rhizome divisions provide a more uniform plant stand and reduce the time from planting to root harvest. On a practical note, large quantities of seed were not readily available when this article was written.   To propagate by rhizome divisions, cut rhizomes into sections, 2 to 3 inches in length, making sure at least one bud is attached to each piece. Up to 15 buds can be on the rhizome of one black cohosh plant. Fibrous roots connected to the rhizome pieces should remain attached. In a well-prepared bed, 3 to 5 feet wide, plant the rhizome pieces deep enough to cover the top of the rhizome with 2 inches of soil. Stagger plantings 18 to 24 inches apart, making sure the bud is pointed upright when placing the rhizome pieces in the ground. Cover beds with at least 3 inches of shredded hardwood bark mulch or leaf mulch. Add mulch as needed throughout the life of the planting to retain soil moisture and retard weed growth. Roots should be ready to harvest three to five years after planting.   Black cohosh seeds must be exposed to a warm/cold/warm cycle before they will germinate. The easiest way to grow plants from seed is to harvest the mature seed in the fall and then sow in the ground immediately, allowing nature to provide the necessary temperature changes. To do this, collect the seed when the capsules have dried and started to split open and the seed "rattle" inside. Plant them 1½ to 2 inches apart, approximately ½-inch deep in shaded, prepared seed beds. Cover with a 1-inch layer of hardwood bark or leaf mulch and keep moist. Some germination may occur the following spring, but most seeds will not emerge until the second spring. To speed up and improve germination, herb grower Richo Cech suggests exposing the seeds to warm temperature (70°F) for two weeks, followed by cold temperature (40°F) for three months.   If you purchase seed, ask how the seeds have been handled, whether they have been stratified (exposed to warm and cold temperatures) and for how long, and what the anticipated germination rate is. Purchased seed often has a much lower germination rate than seed that you collect yourself and sow immediately. Purchased seed frequently takes two years to germinate after sowing. Transplant seedlings into regular planting beds when a second set of true leaves emerges. Roots should be ready to harvest four to six years after seeding.   Insects and Diseases Common diseases found on black cohosh consist of several leaf spots and root rots, including rhizoctonia. Rhizoctonia solani can cause damping off of young, emerging black cohosh seedlings. Control of rhizoctonia may be achieved by planting in well-drained soils and by not planting black cohosh in the same place you grew it before. Leaf spots can cause premature defoliation of the plant, reducing root growth and seed set. To prevent leaf spots, avoid planting in areas with poor air circulation and do not crowd plants. Once the disease is identified, collect and destroy all foliage with the disease symptoms. If more than a few plants are infected, and a positive identification of the disease has been made, an organic fungicide may be applied. No studies on the control of leaf spots on black cohosh have been published, but the Organic Materials Review Institute (www.omri.org/) can be consulted for organic fungicides that can be tried.   Common insects that attack black cohosh include cutworms and blister beetles. Consult the Organic Materials Review Institute (www.omri.org/) for approved organic insecticides that can be tried. Other pests that forage on black cohosh include deer, opossum, rabbits, slugs, and snails. Fencing and repellents may be effective in deterring these pests.

Harvesting, Cleaning, and Drying Most black cohosh is harvested in the fall before the plant dies back. At this time, the roots are at their peak in weight and bioactive constituents. A few buyers will also purchase fresh black cohosh roots in the spring. The entire root, including rhizome and fibrous roots, is harvested. Digging is usually done by hand using a spading fork.   Shake the harvested roots free of soil and carefully separate out any roots that are not black cohosh. All soil, sand, rocks, and other foreign matter must be removed. Protect the freshly harvested roots from the sun and heat and do not allow them to dry out. If the roots are to be used as planting stock, they should be planted immediately or mixed with moist sphagnum moss and stored in mesh bags, burlap bags, or cardboard boxes in a cooler at about 40°F. Check often to make sure that the roots do not dry out, and stir the roots frequently to aerate and prevent mold and mildew. If the roots will be sold for processing into an herbal product, wash them carefully with a pressure water hose or a root washer. A common root washer consists of a rotating drum with water nozzles positioned to spray the roots as they tumble, thoroughly cleaning them.    It cannot be stressed enough how important it is to remove all soil and sand from the roots. This can be challenging because of the knotty nature of black cohosh roots. Some roots will need to be cut to get them clean, but dirty roots will bring a low price or be rejected by the buyer.   To ensure the safety of your herbs for human consumption, follow the recommended Good Agricultural Practices shown at the website for the American Herbal Products Association (www.ahpa.org/) and be sure that your material will meet the federally mandated Good Manufacturing Practices shown at the website for the U.S. Food and Drug Administration (www.fda.gov/Food/DietarySupplementsGuidanceComplianceRegulatoryInformati...).   If a dried product is desired, once the roots are clean, dry them at low heat with high airflow. If a special herb dryer is not available, a food dehydrator, a bulk tobacco barn, or a small room outfitted with racks, a heater, dehumidifier, and a fan can be used. There are several different temperature regimes for drying black cohosh, but the simplest one is to dry them at 80°F to 95°F (if the outside air is very humid, the temperature may have to be increased) for several days to a week. Once the roots are completely dry, store in burlap bags, polysacks, or cardboard drums in a cool, dark, and dry location. Keep no longer than one year. The dry-down rate for black cohosh is approximately one-third of its fresh weight. Potential yield per acre of the dried roots ranges from 750 to 2,500 pounds.   Marketing and Economics Annual Consumption and Dollar Value Black cohosh continues to experience a significant increase in demand, which has been satisfied by additional wild-harvest material coming to market.   In 2000 around 118,000 pounds of dried A. racemosa were sold on the international market. In 2003, there was a peak in consumption at 320,000 pounds valued at almost $2 million. Strong interest in alternative herbal therapies for women’s health issues may have led to this peak of consumption, with more companies using black cohosh in supplements supporting women’s health.     In 2005, the American Herbal Products Association (AHPA) reported that almost 154,000 pounds, valued at approximately $918,000, of fresh and dry material were sold on the market, with 95 percent being from wild-harvested sources. There was a sharp increase in consumption the following year, with over 300,000 pounds of A. racemosa on the international market, followed by a slight increase of consumer consumption to 360,000 in 2007.    Harvest volume decreased again in 2008 and 2009, most likely due to oversupply of A. racemosa, with 291,000 pounds and 170,000 pounds being consumed, respectively. From 2007 through 2009, 99 percent of the supply on the world market was from wild-harvested sources. 2010 saw a rebound in volume, with 327,000 pounds being traded, with 96 percent being from wild-harvested sources. From 2000 to 2010, 2.7 million dry pounds of A. racemosa entered the world market. This equates to between 40.4 million to 54 million A. racemosa plants harvested for the medicinal herb trade over 10 years.   Supply and Demand Most of the supplies of black cohosh come from harvesting of native populations. Wild populations are becoming unstable, and many of the large, easily harvested populations have already been exhausted. Although prices have risen recently, a strong response among growers to cultivate this material has not been triggered, and only small quantities of cultivated material make it to market. Accelerating demand in the face of uncertain supplies may lead to major imbalances that can only be alleviated in the short run by substantially higher prices.   Black cohosh buyers are located throughout the natural range of the plant but are most prevalent in the southeastern United States because that is where the largest concentration of wild populations exists. Cultivation efforts are currently under way in the United States and Europe, but only about 5 percent of the 2005 harvest was generated from cultivated sources. Buyers of black cohosh are searching for reliable supplies and emphasize the need for wild-simulated black cohosh.   The demand for black cohosh from all major wholesale buyers for the 2010 growing season was high. Of 15 major medicinal herb buyers contacted, 80 percent named black cohosh as one of the top three herbs most difficult to find at that time. This could be a significant opportunity for forest farmers wanting to participate in the industry. Prices for organic cultivated black cohosh are about 60 percent higher than that of wild-harvested. As the supply of black cohosh continues to diminish, prices are expected to steadily rise.   With growing health concerns over HRT treatments on the market, many health professionals are looking to black cohosh and other natural substances as potential treatment options for hormone depletion. Positive clinical results for black cohosh as an alternative for HRT continue to drive demand for this material. Demand for cultivated product will continue to increase as natural populations decline and become more widely dispersed. Just a few decades ago, the majority of the black cohosh that was harvested was sent to Europe for processing and consumption. While the majority is still sent to Europe, in the past 10 years, interest from North American companies for this botanical has increased dramatically.     Pricing In 2012, growers and wild-harvesters of black cohosh were receiving an average of $5 to $7 per dry pound. Wholesale prices of dried, cut, and sieved black cohosh root averaged around $15 per pound, while retail prices are around $32. It should be noted that one large retail company was selling cultivated organic black cohosh for $44 per pound, while their wild-crafted black cohosh was being sold at a much lower price of $27 per pound. This could be a sign that the industry is placing more value on cultivated sources as wild-harvested sources continue to be depleted at a steady rate.   High levels of triterpene glycosides in the range of 2 percent, as well as isoflavones, are the primary customer requirements for this material. An increasing number of buyers are requiring organic certification for this botanical.   Distribution Channels Renewed interest in this material by pharmaceutical companies, in addition to scarce supply of raw material, has led to larger companies wanting to contract directly with wild-harvest suppliers. Interest in cultivation, particularly organically certified cultivation, also has increased although there is no evidence to suggest that organic cultivation is occurring on a large scale. The largest buyers are actively pursuing integrated cultivation options, but players of every size exist in the business. Higher root prices will continue to keep small collectors foraging for natural populations.   Black cohosh also is gaining popularity among shade gardeners, nursery container growers, and landscapers. Selections of native species are available as well as varieties with purplish leaves and stems. As a background plant in a shade garden, the gracefulness of this plant in flower is likely to be noticed. In 2012, nursery containers range in price from $3.95 to $10.00 per plant.   Commercial Visibility Black cohosh continues to be one of the fastest-growing herbal products. Of the leading nutraceutical/botanical companies in the United States and Europe, 46 percent offer black cohosh as a standalone product, and 65 percent offer this material as either a standalone product or as part of a multi-constituent supplement.   Conclusion Private forest landowners throughout the plant's natural range have the potential to become major producers of forest-farmed black cohosh. Native populations of black cohosh can still be found, but they are diminishing, making this an attractive prospect for forest farming. Now more than ever, there is great concern over the plant’s sustainability as many black cohosh sites have dramatically decreased in size. Many stakeholders in this industry—from buyers to botanists—are stressing the importance of forest farming of this and other non-timber forest products.    Commercial interest in this material has never been greater. Naturally occurring populations will not satisfy the expected increase in demand of 30 to 40 percent annually over the next three to five years. Lack of significant cultivation creates an opportunity for private forest landowners to fill the gap in supply as wild populations continue to decline.   This material has never traded in a very high price range for a sustained period of time, but its current price is starting to move upward. Significant quantities of this product are already trading on world markets. It is expected that cultivated material will become more prevalent in the supply chain as prices continue to increase 10 to 20 percent annually over the same period. Overall supply will slowly increase but not at a rate commensurate to growth in demand. This factor should keep prices moving upward with moderate momentum.   Resources Cech, R. 2002. "Growing At-Risk Medicinal Herbs." Horizon Herbs. Williams, OR.   Davis, J.M. and J. Greenfield, (eds.) 2003. Analysis of the economic viability of cultivating selected botanicals in North Carolina. A report commissioned from Strategic Reports for the North Carolina Consortium on Natural Medicinal Products by North Carolina State University, Raleigh, NC.   Persons, W.S. and J.M. Davis. 2007. Growing and Marketing Ginseng, Goldenseal, and Other Woodland Medicinals. Bright Mountain Books, Fairview, NC.   Reeleder, R.D. 2003. The ginseng root pathogens Cylindrocarpon destructans and Phytophthora cactorum are not pathogenic to the medicinal herbs Hydrastis canadensis and Actaea racemosa. Canadian Journal of Plant Pathology 25(2):218-221.   Sturdivant, L. and T. Blakley. 1999. Medicinal Herbs in the Garden, Field, and Marketplace. San Juan Naturals, Friday Harbor, WA.   US Department of Agriculture, Crops Research Division, Agricultural Research Service 1960. Index of Plant Diseases in the United States, Agricultural Handbook No. 165. Washington, DC.    Authors

Jeanine Davis, PhD, Extension Horticulture Specialist;

Alison Dressler- Research Assistant

Department of Horticultural Science

North Carolina State University

Revision of Articles Written by Jackie Greenfield, Jeanine Davis, and Kari Brayman

  Mountain  Horticultural Crops Research & Extension Center,  455 Research Dr. Mills River, NC 28759  

This article is a revision of two manuscripts. One was published in 2004 for the North Carolina Consortium on Natural Medicines, a Golden LEAF Foundation-funded project of the University of North Carolina-Chapel Hill and North Carolina State University. The original article was authored by Jackie Greenfield and Jeanine Davis and can be found at www.ncmedicinalsofnc.org. The second manuscript was a revision of the first one and was published in 2006 as a Horticulture Information Leaflet with North Carolina State University. It can be found at www.ces.ncsu.edu/depts/hort/hil/pdf/hil-135.pdf. It was authored by Jackie Greenfield, Jeanine Davis, and Kari Brayman.

  A special thanks to the American Herbal Products Association’s contribution to this leaflet with their continued consultations and their invaluable annual Herbal Tonnage Reports.   Development of the latest version of this leaflet was funded by a grant from the Golden LEAF Foundation and administered by Advantage West. The project is the WNC Natural Products Project and includes the following partners: AdvantageWest, Bent Creek Germplasm Repository, Bionetwork Biobusiness Center, Blue Ridge Food Ventures, North Carolina State University, and Western Carolina University.   

 

Pasture Management on Organic Dairy Farms: Calculating Paddock Sizes, Dry Matter Intake (DMI), and Acreage Needed

ven, 2013/03/15 - 23:48

eOrganic author:

Sarah Flack, Sarah Flack Consulting

Source:

Adapted with permission from: Mendenhall, K. (ed.) 2009. The organic dairy handbook: a comprehensive guide for the transition and beyond. Northeast Organic Farming Association of New York, Inc., Cobleskill, NY. (Available online at: http://www.nofany.org/organic-farming/technical-assistance/organic-dairy, verified 18 July 2012).

Introduction

This article provides an overview of how to size paddocks and estimate the number of acres of pasture needed for a dairy herd. It is also helpful to attend a grazing workshop or school to learn how to set up a pasture system, estimate dry matter, and gain other important grazing skills that this series does not address in detail.

In a management intensive grazing (MIG) system, cows graze pasture rapidly down as short as two inches, then plants are permitted to grow back up to at least eight inches. The density of plants in the pasture will have a large influence on how much available dry matter is in the pastures. If the plants are far apart (low density) and soil can easily be seen between the plants, there will be far less dry matter per acre in the pasture. The best way to learn how to estimate dry matter is to attend pasture walks or workshops. The density and quality of pastures will increase with good grazing management.

The amount of pasture dry matter an animal will eat depends on many factors, including lactation, growth, animal size, supplemental feed, and pasture height and density. A reasonable estimation of the amount of dry matter intake (DMI) that a lactating cow can harvest by grazing well-managed pasture is at least 3% of her body weight. This means, for example, a 1,000 pound cow will eat 30 pounds of pasture dry matter per day. Note that this is just an estimate of pasture DMI and assumes some additional feeding in the barn. It is always best to use real numbers from the farm.

Figure 1. Example of a correctly sized paddock with a high stocking density on Massachusetts farm. Photo credit: Sarah Flack, Sarah Flack Consulting.

Paddock Size

The paddock sizes will depend on how many animals are in the group, how long they will be in the paddock, and how much feed is in the pasture (see Figure 1). The following example calculates the paddock size needed for a herd of 50 Jerseys on a farm where they receive a fresh paddock after each milking. Refer to the pasture Worksheet 1 at the end of this article to plug in the example data. After following along with the example, try calculating the required paddock size for your milking herd.

Example 1 Using Worksheet 1
  • Line 1: Enter the estimated weight per cow of 1,000 lbs.
  • Line 2: Enter 3%. Note that on this example farm they plan to supplement with some dry hay and grain in the barn.
  • Line 3: Multiply 1,000 lbs. x 0.03 to get 30 lbs. of DMI from pasture per cow.
  • Line 4: Multiply 50 cows x 30 lbs. DMI to get 1,500 lbs of DM needed for the herd per day.
  • Line 5: This example farm has decided to use a pregrazing height of 8 inches and has estimated their pasture plant density to be “average.” Use the chart in the worksheet to get an average pasture mass or dry matter per acre. According to the chart, the pasture mass is 2,600 lbs. Enter 2,600 lbs. on line 5.
  • Line 6: This example farm has decided to have the herd graze the pastures to approximately 2 inches. Using this information in the same chart you used above, enter 1,200 lbs. on line 6.
  • Line 7: Calculate 2,600 lbs. – 1,200 lbs. = 1,400 lbs. This is the estimated amount of DM available for the herd to eat per acre.
  • Line 8: Divide the amount of DM required (line 4) by the amount available (line 7) to calculate the number of acres needed: 1,500 lbs. ÷ 1,400 lbs. = 1.07 acres.

Note that this is the number of acres needed per day (24 hours) to feed the herd. Since this example farm decided to give them a new paddock after each milking, or two paddocks a day, the half-day paddocks will be 0.54 acres each (1.07 acres ÷ 2 = 0.54 acres after each milking).

This method of paddock size calculation is a good place to start. It will be necessary to adjust the actual paddock size based on several factors including:.

  • How much feed is being fed in addition to pasture? This will affect how much DMI they actually need from the pasture.
  • Pasture height—the plants must be tall enough. Plants too short will not allow cows to get enough DMI even if you make larger paddocks.
  • Weeds, rocks, swamps, and other things in the pasture will need to be factored in.
  • Plant density may be lower or higher than estimated.
Total Number of Pasture Acres Needed

The number of paddocks or total number of acres of pasture needed, can be calculated if it is known how long the pastures will need to regrow after each grazing. Research done by Dr. Bill Murphy in Vermont produced the following average regrowth periods. The regrowth periods on different farms and different parts of the country will likely be shorter or longer.

  • 12–15 days in late April to early May
  • 18 days by May 31
  • 24 days by July 1
  • 30 days by August 1
  • 36 days by September 1
  • 42 days (and longer) by October 1

Information on the actual amount of time needed for complete regrowth in different parts of the country can be found at the local USDA Natural Resources Conservation Service (NRCS) office, county extension office, or from a grazing consultant.

Example 2 calculates the total number of pasture acres needed for the example farm discussed earlier in this section, and uses the average Vermont regrowth numbers listed above.

For grazing planning, it is helpful to keep records of how often and for how long each paddock is grazed each year. Records can be kept on a copy of the farm map, in a notebook or worksheet which includes the date, where the animals grazed, and for how long. These records will provide information on the actual rest periods throughout the growing season. Walking regularly through all the pastures at least once each week and recording how many inches each paddock has grown back is another way to collect information on regrowth periods and can also provide information on which order to graze the paddocks.

Example 2 Grazing Acreage Needed

For the 50-cow farm that needs 1.07 acres per day, total acreage needed to graze in the spring will be 16 acres (1.07 x 15 days = 16 acres). When pasture growth slows down to 35 to 40 days, the total needed acreage increases to 38 to 43 acres.

If the total pasture acreage is not increased as regrowth periods increase, plants will not get enough rest and dry matter intake by animals will drop, resulting in poor animal and pasture performance.

What if There is Not Enough Land?

Once the number of acres needed to set up the grazing system has been calculated, it may become clear that the farm does not have enough land suitable for grazing within cow-walking distance of the milking facility. In some cases, unless additional land can be obtained, the farm may not be a good candidate for organic certification. Plan ahead to make sure the amount pasture acreage meets the needs of each group of livestock throughout the entire grazing season.

Extending the Grazing Season

If there is enough land, it may be possible to plan grazing so that pasture can be available into the fall and even winter in some climates. This requires careful planning so that plants are tall enough when growth stops. Some conditions such as excessive soil moisture or too much snow can make fall stockpiled grazing difficult. For some farms, however, this is a successful way to feed forages. Refer to "Managing Dairy Nutrition for the Organic Herd: Managing Seasonal Diet Shifts" for more information on stockpiling and nutrition.

Grazing during Excessively Wet Weather

During some weather conditions, grazing some or all of the pastures may not be possible. Flooding makes it necessary to either move livestock to high dry land or keep them in the barn. Anytime grazing is not possible due to an emergency like this it is important to make sure the organic standards are being followed. § 205.239 lists the detail on exemptions to the grazing requirements of the organic standards.

High rainfall periods may result in muddy pastures or lanes that make grazing difficult and may even cause hoof or other health problems. Building well-surfaced lanes, using culverts, filter fabric under surface material, and other techniques will make the grazing system much easier to manage in these weather conditions.

Drought Conditions

As global climate change causes more extreme weather conditions, all farms will need to prepare for extended dry periods. Planning for possible drought may mean saving extra stored forages that can be fed during a drought. Other techniques being used successfully by farmers who regularly experience summer droughts include grazing annual crops such as millet or sorghum-sudangrass as well as adding significant acres of hay land which is mechanically harvested early in the growing season.

Worksheet 1. Calculating Paddock Sizes and Number of Acres Needed.

Attending pasture workshops is a great way to learn how to make these estimates more accurate.

Estimating Forage Dry Matter Intake (DMI)

Line 1: Average body weight:____________________

Line 2: Estimated DMI (as % of body weight):____________________

Line 3: Daily DMI required for single animal (Line 1 x Line 2):____________________

Line 4: Daily DMI required for herd (Line 3 times number of animals):____________________

Estimating Pasture Mass (Forage Dry Matter)

Height

Average Density* Low Density High Density (inches) (Pasture pounds DM/acre) (Pasture pounds DM/acre) (Pasture pounds DM/acre) 8 2,600 2,200 2,800 6 2,400 2,100 2,600 4 1,800 1,500 2,100 2 1,200 1,000 1,400 1 900 600 1,000 *Pounds of dry matter per acre at each height varies widely with plant density and species. Calculating Available Dry Matter

Available forage dry matter = Pre-grazing mass - (minus) Post-grazing mass

Example:

Pre-grazing at 6 inches:       2,400
Post-grazing at 2 inches:   - 1,200
1,200 lbs. DM/acre

Your Farm:

Line 5: Pre-grazing mass:____________________ +

Line 6: Post-grazing mass:____________________ =

Line 7: Available pounds DM/acre:____________________

Calculating Paddock Size

Paddock size (in acres per day) = Daily DM required ÷ Available dry matter

Daily DM required _____ (Line 4) ÷ Available DM/acre _____ (Line 7) = Paddock size in acres/day (Line 8)

(There are 43,560 square feet in an acre, which is a square about 210 feet on each side)

Calculating Rest Period

Maximum possible rest period = Your total pasture acres ÷ Paddock size

Your pasture acres available _____ ÷ Paddock size in acres per day _____ (Line 8) = maximum rest period

Also in This Series

This article is part of a series discussing pasture management on organic dairy farms. For more information, see the following articles.

References and Citations
  • Emmick, D., K. Hoffman, and R. Declue. 2000. Prescribed grazing and feeding management for lactating dairy cows. USDA Natural Resources Conservation Service, Syracuse, NY.
  • Murphy, W. 1998. Greener pastures on your side of the fence. Arriba Publications, Colchester, VT.
  • Robinson, J. 2004. Pasture perfect. Vashon Island Press, Vashon WA.
  • Smith, B. 1998. Moving ‘em: A guide to low stress animal handling. Graziers Hui, Kamuela, HI.
  • Undersander, D., M. Casler, and D. Cosgrove. 1996. Identifying pasture grasses. University of Wisconsin-Extension Bull. #A3637. University of WI, Madison, WI. Available online at: http://learningstore.uwex.edu/pdf/A3637.pdf (verfied 5 Sep 2012).
  • Zartman, D. L. 1994. Intensive grazing seasonal dairying: The Mahoning County dairy program, 1987–1991. OARDC Research Bull. 1190 (1-49), OH Agric. Res. and Development Center, OH.
Additional Resources

 

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.

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