The sustainable agriculture farming system project in California's Sacramento Valley

The Sustainable Agriculture Farming Systems project (SAFS) was established in 1988 to study the transition from conventional to low-input and organic crop production practices. The project includes four-year crop rotations under conventional (conv-4), low-input, and organic management and a conventionally managed, two-year rotation (conv-2). Positive effects on soil quality resulting from low-input and organic management include increased soil organic matter, a reduction in soil-borne diseases, increased pools of P and K, higher microbial biomass and activity, an increase in mobile humic acids and increased water infiltration rates and soil water-holding capacity. Pesticide use in the low-input cropping system is about 25% of that used in the conventional systems. The most profitable farming system continues to be the conv-2 system due to the greater frequency of tomato in that rotation. Among the four-year rotations, the organic system, in which the produce commands premium prices, is the most profitable, although least profitable if premium prices are not applied. Information generated from SAFS research has been disseminated via videotape, workshops, annual field days, field tours, educational materials, peer-reviewed articles and an Internet homepage. Future challenges for the SAFS project include development of reduced-tillage and cover crop management strategies to optimize N availability following cash crops; weed management in organic and low-input systems, improvement of water-use efficiency in alternative systems and sequestration of C in the soil.