New Tools and Techniques for High Residue Organic Vegetable Strip Tillage in the Maritime Pacific Northwest.

Many maritime Pacific Northwest organic vegetable growers aim to reduce the frequency and intensity of tillage as a means to improve soil quality, but have concerns about negative effects on weed management and soil temperature as well as lack of appropriate equipment. Winter cover crops are an integral component of organic reduced-tillage systems because they cover the soil during the winter, suppress winter weeds, and can be converted to a mulch capable of suppressing summer annual weeds. Large amounts of cover crop residue can, however, reduce soil temperature and interfere with planting and weeding. To improve strip tillage effectiveness in organic vegetable production, three new tools and techniques are being trialed in research station and on-farm trials in western Washington: 1) PTO-driven strip tillage, 2) strip-planting cover crops, and 3) continuous minimum tillage. PTO-strip tilling increased soil temperatures relative to no-till, but soil temperatures and yields of warm-season crops were lower than full tillage. Planting cover crops in distinct strips to place high biomass rye outside of cash crop planting strips and lower residue, leguminous cover crops in the planting strips reduced cover crop residue in the cash crop planting strip. For continuous minimum tillage fall cover crops were planted without soil inversion; soils were disturbed with an undercutter to reduce weed pressure then cover crop was sown with a minimum till drill. With the minimum till treatment, cereal rye cover crop biomass was equal to full till, though vetch biomass was larger in full till.