Cover crops help clean water

University of California soil scientists and irrigation experts have teamed up on a sustainable agriculture project that looks at the water-cleansing effects of cover crops—plants grown to reduce weeds and improve or protect the soil, rather than being harvested.

Researchers from the UC Davis Sustainable Agriculture Farming Systems project will examine what happens when cover crops are planted and the resulting debris is left in the furrows.

"Slowing irrigation water down in the furrows increases the water soil penetration and reduces the amount of runoff that enters streams and rivers," says Will Horwath, one of the project's lead researchers and a professor of soil biogeochemistry. "It's one of the farming practices that has been identified as a sustainable way to prevent nutrients and chemicals from the fields from entering drinking water supplies, and for recharging groundwater supplies."

Some California farmers, however, have been hesitant to adopt reduced tillage and cover-crop practices because of the cover-crop residue that is left behind in the field. Horwath hopes this study will help answer many of their questions.

The main research site for the project is UC Davis' Russell Ranch Sustainable Agriculture Facility. Russell Ranch is home to the Sustainable Agriculture Farming Systems project, which has examined sustainable farming practices for almost 20 years.

Measurements also are taken at farms in neighboring Yolo and Stanislaus counties to identify relationships between management practices and runoff in different areas. The cover-crop project relies on input from growers and farm advisers as part of the research team.