SARE 1997 Highlights

Bedding System Cuts Vegetable Risks

Low-cost cover crop methods can reduce soil-nitrate leaching by 37 to 70 percent without hurting yields in intensive vegetable production systems, a SARE-funded study in California's Salinas Valley shows. Growers of iceberg lettuce and broccoli there are using plant residues to build soil fertility, while helping reduce water contamination from nitrates. The three-year study fine tuned an efficient system of incorporating winter rye or phacelia cover crops using reduced tillage on semi-permanent beds. Building beds in fall and over watering easily incorporated cover crops help ensure timely seeding of vegetables even if spring conditions have been wet. The system eliminates disking flat ground in spring and rebedding. A California wildflower bred for cover cropping, phacelia is a succulent plant that decomposes readily. Merced rye is another common cover crop with rapid growth and a vigorous root system. Growers mow the covers and wait four weeks before planting vegetables. This reduces microbial competition for soil N without missing the planting window and with little or no risk of disease or pests, results show. Hundreds of food system representatives attended field days and workshops describing project results. Many growers requested cover crop seed and offered to participate in future on-farm research. (Western Region project AW92-6.)

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