Long-term Organic Systems Research in Horticultural Food Crops in the "Salad Bowl of America"

Long-term agricultural systems research is crucially important to understand the sustainability of various management practices and provide robust information needed to develop more efficient food production systems.  Such research is particularly important and yet extremely uncommon for high-input horticultural crops where there is high risk of nutrient leaching, and in organic systems where certification standards limit pest control strategies and soil fertility management is based on organic matter inputs.  While long-term systems studies with agronomic crops have provided important insights, it is questionable if these are relevant for horticultural systems that are significantly more input-, tillage-, and management-intensive, highly dependent on hand labor, and focused on product quality over quantity.  The Salinas Organic Cropping Systems (SOCS) trial is one example of long-term horticultural research, and is the longest running organic systems study focused on high-value, high-input, cool-season horticultural food crops in the U.S.  This ongoing nine-year trial is located in the heart of Salinas Valley on the central coast of California.  This region is known as the "Salad Bowl of America" because it produces and exports more cool-season vegetables than any region of the U.S.  The SOCS trial focuses on cover crop and compost effects in eight certified organic systems that produce lettuce, broccoli and strawberries.  The trial uses a unique research approach whereby commercial-scale production occurs on USDA–ARS land with collaborative assistance from local organic farms to help offset research costs.  This collaboration enhances the credibility and support for the research through involvement of industry, and ensures that production quality standards are met because the produce from the research is marketed by the collaborating farms.  Like most long-term agricultural research, the SOCS trial began as a short-term (i.e. 2.5 year) study and evolved into a long-term study.  The objectives of this presentation are to: 1) describe the evolution of the trial; 2) provide examples of unique challenges to develop and manage long-term systems research for high-input, high-value, tillage-intensive horticultural crops; 3) share some lessons learned while developing and managing the SOCS trial; and 4) highlight some of the unexpected results from the first nine years of the trial.