UC Cooperative Extension alerted us to a way to save some water and improve soil conditions.
Since 1999 UC researchers, farmers on the west side of the valley and Natural Resource Conservation Service conservationists studied cotton and tomato production by comparing fields with cover crops and no tillage to fields with standard tillage.
Applying 8 inches of supplemental irrigation over the 14-year period, researchers found cover crops produced more than 19 tons of organic material per acre. The nitrogen from the no-tillage cover crop generated 59 percent more nitrogen.
The water conservation factor came from the no-tillage cover crop being able to hold more water and reduce runoff.
This approach is used by a number of local wine grape growers, who maintain ground cover between their vine rows. It requires some mowing while the grass is growing, but it aids the wines by adding nitrogen to the soil, depending on what is used as a cover crop. And it aids water retention, keeping the soil cool.
Many local farmers also do soil testing with instruments that can measure the soil moisture and help the farmer avoid overwatering.
The UC conclusions about the value of cover cropping are an additional tool for local farmers to add to their repertoire.
“Attributing ecosystem services to farming is an emerging trend in assessing agricultural operations,” said Jeff Mitchel, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis. “Resource management systems on today’s farms can provide significant benefits to air, water and soil resources and furnish wildlife habitat. We’ve determined that farmers who use cover crops and no-till practices are furnishing still more ecosystem services.”