Final report for LS22-371

Project Type: Research and Education

Funds awarded in 2022: $360,000.00

Projected End Date: 09/30/2025

Grant Recipients: National Center for Appropriate Technology; Southeastern African American Farmers Organic Network (SAAFON); Operation Spring Plant (OSP)

Region: Southern

State: Texas

Principal Investigator:

Justin Duncan

National Center for Appropriate Technology

Co-Investigators:

Dorathy Barker

Operation Spring Plant (OSP)

Jason Lindsay

SAFFON

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Project Information

Abstract:

During recent research on cover crops in the Lower Rio Grande Valley of Texas, we noticed an anomaly: after a winter planting of crimson clover, pigweed germination was reduced by 95%. Pigweeds (Amaranthus spp) are fast-germinating and fast-growing annual summer weeds found in crop lands throughout the country. We wondered why pigweed was suppressed so greatly by crimson clover. Was it allelopathy or some other factor? Woolly croton, sunflower, and Parthenium were also suppressed to varying degrees by crimson clover, well into the next summer growing season. We have noticed through the years that some cover crops do better than others at controlling specific weeds. For example, in South Texas, pigeon peas suppress sunflowers especially well. And in earlier trials Austrian winter peas showed promise for control of Bermuda grass and nutsedge. These anecdotal findings lead us to wonder if some of these weed suppressing effects can be proven in controlled studies and what other weed/cover crop pairings might be suitable for southern farms. In this research and education project, we worked with limited-resource producers in four southern states, carrying out controlled studies to test the efficacy of various cover crops in suppressing some of the most troublesome weeds. In the process of carrying out these studies, underserved and limited resource farmers in several states gained firsthand experience with cover crops. Producers from the Southeastern African American Organic Network SAFFON), Operation Spring Plant (OSP), and our established collaborators in Texas took inventory of their weeds each season. Based on these inventories, we developed a cover crop selection tool based on cover crop properties and water demands. Knowledge gained from this research and the cover crop selection tool are being disseminated at conferences such as the Texas Organic Farmers and Gardener’s Association (TOFGA) and Southern Cover Crops Council, NCAT’s ATTRA website, partner organization websites, and various social media channels including blogs, Facebook posts and podcasts.

Project Objectives:

1: Expand the knowledge base concerning which cover crops work best for specific weeds in the South.

2: Expand usage of cover crops by limited-resource producers throughout the South to achieve weed suppression on farm.

3: Develop cover crop selection tools for southern farms.

4: Collect the stories of the farmer cooperators and older farmers about how to deal with weeds in a guide that also includes agronomic data about cover crops so the next generation can benefit from their knowledge.

Cooperators

Click linked name(s) to expand/collapse or show everyone's info

Dr. Richard Griffin - Technical Advisor
Professor
PVAMU (1890 Land Grant)

Research

Materials and methods:

Farmers in the three organizations networks--OSP, SAAFON and NCAT, grew various cover crops to determine which cover crops suppress certain weeds in their fields. To assist the participating farms with conducting the on-farm research, the project team conducted group meetings to initiate discussions about the cover crop project and to ensure the stakeholders comprehended the project plans. Following the group meetings, one-on-one meetings with the farmers were conducted. These sessions were a platform for the project team to distribute seeds, create detailed implementation plans, mark off specific plots for the cover crops, and address any questions or concerns raised by the farmers. Each farmer was presented with a comprehensive plan that included what seeds would be provided, plot layout and measurements, and how to report their findings. Farmers planted their first session of cover crops in October and continued to monitor their crops throughout the winter months. Farmers planted wheat, cowpeas, buckwheat, lima beans, winter rye, clover, and fescue. Plots were fifty-two feet wide and 156 feet long. The 52-foot side was broken into (3) 17ft lengths. The 156ft long side was broken into (6) 26ft lengths. This yielded eighteen subplots to be planted by pattern. Cover crops were terminated in March. Farmers planted a spring cover crop by first discing the remnants of the previous cover crops. Cover crop seeds were then planted with a hand-held broadcast seeder. A smoothing harrow was used to promote seed to soil contact and increase germination rates. In July, farmers began planting ten pounds of each of their summer cover crops of buckwheat, cowpeas, peanuts, sudan grass, and sweet potatoes. Farmers observed their crops over throughout the growing season and following the same layout as previously stated.

Field being prepped for planting

Research results and discussion:

One farmer reported the October planting of winter rye, wheat, and fescue was successful with little to no weeds present.

Another fall crop of wheat with turnip salad was sowed by hand without fertilizer. It started well. By Spring, weeds and deer overtook the salad. The field was then prepped for a summer planting.

Another October planting of wheat cover crop sowed with purple top turnip salad with no fertilizer. The wheat thrived with very little weeds. The farmer reported that the wheat was so thick that it dominated the turnip salad.

The spring planted clover and winter rye grass was successful. It rained right after planting so the crops germinated well. Some varieties of weeds grew amongst the rye and the clover. All in all, the weeds were minimal and the crops grew well.

The summer planted cover crops thrived in protecting the soil but did little to minimize the weeds. Various weeds were reported, including Johnson grass, red-root pigweed, and giant foxtail. The cowpeas and buckwheat did not do as well as the sudan grass and sweet potatoes. The peanuts did not germinate at all.

All the participating farmers saw an improvement in their soil, and various weeds were present but minimal. Their success in weed control and soil improvement is a testament to the impactful benefits of cover crops. The positive impact on soil quality and nutrient retention, as evidenced by the innovative pairing of turnip salad with cover crops, is a promising sign for the future of sustainable agriculture. While the farmers encountered some challenges with thick growth from cover crops overshadowing the turnip salad and other crops planted like radishes, the overall positive impact on soil quality and nutrient retention cannot be overlooked. The extreme temperatures experienced during this research presented a unique and significant opportunity to study the critical role of cover crops and their soil protection capabilities.

The project created opportunities for farmers across the Southeast to deepen their understanding of cover crops—particularly in relation to native varieties often dismissed as weeds. This approach shifted the focus from simply following a pre-set list of cover crops to a broader principle: recognizing how many crops, including those not typically listed, can provide cover crop benefits. Through this lens, crops such as lima beans (legumes) and sweet potatoes (providing tillage through their bulky roots and soil coverage through their extensive vines) were recognized as valuable cover crop contributors. This perspective encouraged farmers to look at their fields with fresh eyes, understanding how familiar crops and indigenous plants play a vital role in soil health and farm viability.

Participation Summary

14 Farmers participating in research

Education

Educational approach:

For producers in the research project the educational approach is hands-on, learn by doing. Each farmer participant was given a stipend and provided with the basic experimental field map and instructed to plant covers in a randomized complete block design (RCBD) . Once the crops grew, farmers could see differences in weed populations according to the cover crop planted. Project partners coordinated regular meetings to allow farmers to update each other and share insights and results. This peer-to-peer learning resulted in problem solving and greater adoption of practices. Site visits to participating farms allowed farmers to see practical examples of cover crop integration. This hands-on approach was highly valued, offering real-time observation and peer-to-peer teaching. For conference and workshop attendees, cover crop strategies and concepts were presented so that they could learn why cover crops were so important to their operations and have a practical working knowledge of how to integrate them into their operations.

Educational & Outreach Activities

80 Consultations

1 Curricula, factsheets or educational tools

14 On-farm demonstrations

2 Online trainings

3 Tours

10 Webinars / talks / presentations

2 Workshop field days

Participation Summary:

621 Farmers participated

44 Ag professionals participated

Education/outreach description:

January 2023 Operation Spring Plant hosted its annual conference in Raleigh where cover cropping was introduced to 65 producers.
May 2023 Operation Spring Plan hosted an on-farm workshop. 13 participants learned about cover crop implementation.
August 2023 a cover cropping class was conducted in Oxford, NC to 14 individuals, 4 of whom received on site farm visits and consultations.
August 2023 SAAFON hosted a cover cropping class for its farmer participants in Hazlehurst, MS, where 15 participants and 5 SAAFON personnel attended
December 2023 A meeting to explain cover crop research was held with 25 participants.
January 2024 Operation Spring Plant hosted its annual conference in Durham where 150 participants learned about cover cropping.
February 2024 A cover crop presentation was given at the Carolina Farm Stewardship Conference.
April 2024 A farm tour and cover crop class in Balch Springs, TX with 6 people in attendance.
April 2024 A cover crop presentation was given to 25 participants at the SW Arkansas Small Farms Conference.
November 2024 Presentation at the National BUGs conference in Houston, Texas where 210 people learned about cover crops and 50 publications on cover crops were distributed.
January 2025 a cover crop class taught to 80 attendees at the Operation Spring Plant Conference in Wilson, NC.
May 2025 a cover crop class taught to 18 participants at the Austin Organic Gardeners Meeting.

There have been numerous posts on various social media platforms introducing cover crops to producers made by ATTRA and project partners.

Learning Outcomes

14 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation

Key changes:

Plant cover crops
identify weeds

Project Outcomes

14 Farmers changed or adopted a practice

14 New working collaborations

Project outcomes:

This project resulted in on-farm learning through cover cropping trials, peer-to-peer learning, and outreach and education. The project facilitated collaborations between the project team and farmers. Project participants reported increased knowledge of cover crops and their performance in extreme weather conditions. This project resulted in new information, including soil protection, weed suppression, biodiversity, and lessons learned in cultivating specific cover crops. The collective journey of trial and error and dedicated research have led to a wealth of knowledge that the project partners are excited to share with other farmers in our communities. Farmers reported a deeper appreciation for the role of indigenous and non-traditional crops in building soil health. This project expanded the definition of cover crops beyond a static list, encouraging innovation and experimentation. Project partners reported that this project strengthened relationships between farmers, fostering ongoing support and farmer-to-farmer education. The project increased understanding of how nature’s own processes—through native plants and culturally significant crops—can be leveraged for sustainable farming. One farmer noted the value of visiting peers’ farms as the most impactful element of the project, highlighting how practical observation deepened their understanding of soil systems and reinforced the importance of working with, rather than against, natural ecosystems. One farmer reported that once farmers in the project started seeing the results on their research plots, they started planting cover crops and experimenting, even though they we were not officially a part of the project. They were eager to start implementing the practices on their own farms. Project partners collected videos and stories of participating farmers and others impacted by this project. These materials will be used to share experiences and continue education and practice adoption beyond the life of this project. Overall, the project was well-received by participating farmers, who expressed gratitude for the opportunity to learn, share space, and build stronger connections. The project demonstrated that beyond lists and prescriptions, the principle of cover cropping is about working with the land—embracing both traditional and indigenous plants—to sustain soil health and nurture resilient farming communities.

Information Products

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Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.