California Agriculture

Following 4 years of a cotton-tomato rotation on the west side of the San Joaquin Valley, conservation tillage and cover crops altered physical and chemical properties of soil. In conservation tillage systems, bulk density decreased and available concentrations of nitrate and phosphorus increased. In contrast, the conservation tillage system redistributed potassium to the surface of the soil, lost organic matter and increased salt concentrations, all potentially detrimental to plant growth. Cover cropping, on the other hand, increased soil organic matter regardless of the tillage treatment, and increased potassium concentrations. By cover cropping, farmers in this region may improve their soil quality; however, the benefits of conservation tillage to soil quality are fewer and will require more research to determine long-term effects.