Multi-state research will explore benefits and potential risks

The Organic Center is pleased to be a part of a collaboration among university, government, and non-profit partners that will receive a major USDA Specialty Crop Multi-State Program grant to look at the benefits of livestock integration through cover-crop grazing on bacterial population dynamics, soil building, and environmental health.

The nearly $1 million project titled “Evaluating the food safety impacts of cover-crop grazing in fresh produce systems to improve cover crop adoption, crop-livestock integration, and soil health” is led by the University of California, Davis in partnership with The Organic Center, USDA’s Agricultural Research Service, the University of Maryland Eastern Shore, and the University of Minnesota.

“Fresh produce growers and their advisors will benefit from learning about the impacts of integrating livestock grazing with winter cover crop management on soil health including soil organic matter, nutrient cycling and reduced nitrate leaching, and potential food safety risks discovered in this project to make decisions on adoption, management, and environmental benefits of WCC in annual vegetable systems,” said Alda Pires, University of California Cooperative Extension specialist and lead principle investigator in the study.

Livestock grazing of cover crops could be beneficial for organic systems, because it maximizes the strengths of cover cropping, including enhanced soil fertility, structure, water infiltration and storage, and reduced nitrate leaching, while addressing challenges that have limited the expansion of cover crop use. These challenges include concerns over cover crop water use and nutrient immobilization, which could increase deficiencies and increase input costs of the crops that follow.

Many growers consider livestock grazing of cover-cropped fields in fresh produce operations as a way to enhance soil health and environmental benefits by increasing carbon inputs and nutrient cycling.

“This study will allow farmers to complement the benefits of both cover cropping and livestock integration into cropping systems,” said Jessica Shade, the Director of Science Programs from The Organic Center. “Like cover cropping, integrating animals into cropping systems can be beneficial to farm environmental impacts and profitability by improving nutrient cycling, reducing dependence on external inputs, improving soil health, and diversifying profit streams.”

Unfortunately, despite the well-known benefits of animal-crop integration, concerns over microbial food safety are limiting the expansion of animal integration into cropping systems. Recent research has shown that integrated crop-animal systems perform well in keeping pathogens out of meat, but additional research is needed to examine the synergistic impacts of the use of livestock for cover crop grazing on ecosystem health and food safety.

This project will fill this research need by examining food pathogen persistence and survival in soil and transfer to vegetable crops, and the relationship between soil health properties, environmental factors and pathogen survival in grazed cover crop-vegetable production in three states.

Researchers will measure changes in soil health indicators over two years of grazed cover crop-vegetable production, and assess benefits and potential tradeoffs of vegetable cash crop productivity.

The research team is multi-institutional, multi-regional, and interdisciplinary, and includes:

• Alda Pires, UC Davis
• Michele Jay-Russell, WCFS, UC Davis
• Nicole Tautges, UC Davis
• Amelie Gaudin, UC Davis
• Patricia Millner, USDA-ARS
• Fawzy Hashem, UMES, MD
• Paulo Pagliari, UMN
• Jessica Shade, The Organic Center

The Organic Center will help lead outreach efforts focusing on the benefits of grazing and food safety impacts such as online tools, outreach events, conference presentations, and publications targeted to growers, policymakers and consumers.

The Organic Center's mission is to convene credible, evidence-based science on the health and environmental impacts of organic food and farming and to communicate the findings to the public. The Center is an independent non-profit 501(c)(3) research and education organization operating under the administrative auspices of the Organic Trade Association.