Experimental Design and Operational Dynamics of the SAFS Farming Systems Project

Steven R. Temple

The UC Davis Sustainable Agriculture Farming Systems project, or SAFS, was initiated in 1989 by a group of farmers and cooperative extension and Agriculture Experiment Station faculty at the UC Davis campus. The most important goals of this multidisciplinary and participatory effort have included 1) a comparison of conventional, low-input, and organic management of a four-year, five-crop rotation, 2) companion research to improve the performance of the cover crop-driven low-input and organic systems, and 3) extensive distribution of SAFS results and participation by a broad array of Sustainable Ag "stakeholders".

The SAFS "main experiment" consists of 56 plots, 1/3 acre each, and whose 60' by 220' dimensions permit the use of full size commercial row crop equipment. Each of the systems was initiated simultaneously at all 4 temporal points in the rotation to reduce the statistical vagaries of unusual crop x season x system interactions. In addition to the principal 4-year, 5-crop rotations of processing tomato, safflower, field corn, and wheat/double-crop drybeans, we added a 2-year conventional rotation of wheat-tomato designed to more closely simulate the pressure for more frequent and higher value tomato returns in local rotations.

SAFS is currently completing the third rotation cycle (12 years), and much has been learned. Organic premiums, while inconsistent, have proven vital to the economic success of that system. Low-input corn has consistently outperformed the conventional and organic corn. Organic and low-input yields equivalent to conventional yields may be obtained, but production costs are generally higher. The low-input system typically carries some of the risks and farm management demands of the organic cover crop system, but without the price benefits that accrue to certified organic produce.

Insights have been gained into soil processes that mediate the fertility and microbiological dynamics of soil/plant systems. Practices such as transplanting tomatoes have been highly beneficial to the cover crop-driven systems, and transplanting has again become relatively common in many Central Valley tomato systems during the life of the project. Rotating green manure cover crops proved important in managing vetch diseases that led to early cover crop decline. Regular cover cropping has in many ways brought weather more squarely into the farming equation for the low-input and organic systems. Certain management solutions have substantial implications for equipment purchases, capital investments, and the availability and cost of composts and livestock manures. Interesting differences in soil/plant/water relations, and soil physical/structural properties, have begun to appear recently. One's time perspective on evaluating the "sustainability" of these and other systems has become readily apparent.

SAFS group dynamics have contributed immeasurably to the successes we have enjoyed in sustained grower participation, well attended field days, and special workshops. Growers have actively participated in research planning, execution, and interpretation of results. They have also played a consistent role in information and technology transfer, speaking and participating in field and lab panels with PI's and Farm Advisors. Shared project leadership by all PI's is very important in our sense of shared ownership. We spend a lot of time working on a collegial, consensus-seeking process that has stimulated strong multidisciplinary participation. Our commitment to use "best farmer" practices in managing each of the systems has made us further dependent on regular grower input, and the project has benefited immensely. The healthy interaction of farmers, CE Farm Advisors, and Experiment Station researchers has facilitated an environment where many and diverse agribusiness interests have contributed to the Sustainable Ag "agenda", and this in turn has rapidly dissipated the animosity among differing interest groups that existed at the time that SAFS was conceived.

The SAFS research site has hosted a large number of national and international visitors (for varying lengths of time), and been the basis for many graduate student theses. The project group refers to the site as a "living laboratory", and the annual list of formal and informal visitors is substantial. We believe that one of the most important legacies this project will leave is the huge network of collaborators and visitors that make up the mailing list. Another (very tangible) asset is the soil of 56 plots with unique and contrasting 12-year management histories.

Major long-term sponsors of the SAFS project include Western SARE and UC SAREP.

Steven R. Temple
Dept. of Agronomy and Range Science
University of California
Davis, California 95616-8515
Tel: (530) 752-8216
srtemple@ucdavis.edu

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