UC researchers seek organic growers of tomatoes, lettuce, spinach, carrots, radishes or cucumbers.

University of California scientists are seeking certified organic growers to participate in a multistate soil and food-safety study. The researchers are gathering data to develop national guidelines and best practices for using raw manure to improve soil health while minimizing food-safety risks in organically grown crops such as leafy greens, tomatoes and root vegetables.

“The goal of our study is to provide organic farmers with science-based strategies that effectively limit food-safety risks when using raw manure-based soil amendments,” said Alda Pires, UC Cooperative Extension urban agriculture and food safety specialist in the School of Veterinary Medicine at UC Davis.

To study the survival of pathogens in soil and soil health, UC scientists are recruiting California growers who use raw or untreated manure in organically grown crop fields.

To ensure food safety, scientists are studying the best practices for applying raw livestock manure as fertilizer for organically grown produce.

Pires is leading the project in California with Michele Jay-Russell, a veterinary research microbiologist and manager at the Western Center for Food Safety at UC Davis.

The researchers will visit participating farms eight times over the 2017-2018 growing season.

“We will collect produce, water, soil and manure samples,” said Jay-Russell. “All of the samples will be tested for bacterial indicators such as nonpathogenic E. coli and pathogens. We will ask the farmers to complete a short survey. The study is voluntary and all locations and names will be kept confidential.”

Eligible California farms must be certified as organic by the National Organic Program or California Certified Organic Farmers and fertilize with raw manure or untreated manure from dairy cattle, horses or poultry. The farms can grow any of the following produce: lettuce, spinach, carrots, radishes, tomatoes or cucumbers.

For more information or to enroll in the project, please contact Pires at (530) 754-9855 or apires@ucdavis.edu, or Jay-Russell at (530) 219-4628 or mjay@ucdavis.edu.

This study is being conducted in other states by the University of Minnesota, University of Maine, USDA Agricultural Research Service's Beltsville Agricultural Center, USDA Economic Research Service's Resource and Rural Economics Division, Cornell University and The Organic Center. The project is funded by a U.S. Department of Agriculture Organic Research and Extension Initiative grant.