2017 ASHS Annual Conference

A comprehensive soil health management plan integrates multiple practices, such as cover cropping, organic soil amendment and reducing tillage. Ideal minimum tillage systems for vegetables must provide good seed-soil contact, soil temperatures, moisture and fertility to support desired quality, yields and timeliness of harvest. In more northern climates, no-tillage systems have constraints for vegetables, due to cooler soils, poor soil seed contact and few weed control options. In organic systems, nutrient availability can further limit success. For the last ten years, we have focused on improving strip till systems for vegetables grown in northern climates. Zone or strip tillage systems can overcome many of the constraints of no-till but growers are concerned with rotations, equipment, and weed, surface residue and fertility management. Integrating cover crops within strip tillage is a key challenge. Our research program is focused on designing strip tillage systems for vegetables, both conventionally and organically grown. Currently, we are evaluating the effects of overwintering legume cover crops (none, hairy vetch or crimson clover) grown in mixture with cereal rye on N availability and weed suppression in an organic strip-tilled cabbage system. Cover crops were planted in the fall at three research locations, either in mixes or in alternating strips of legume and rye. In spring, cover crops were then managed by flail mowing and retained on soil surface, flail then removal of aboveground biomass, or flailing and incorporated with rototilling. Measures included cover crop biomass and total N and C:N ratio, weed biomass prior to planting, soil inorganic nitrogen 3 weeks after planting, time required to hand weed, final weed biomass and crop quality and yield. Vetch planted without rye provided less than half the above ground biomass, but significantly higher total N contribution (125 lb/a) compared to vetch with rye (100 lb/acre). Cabbage yields were also highest with the vetch only cover crop, regardless of cover crop management strategy (moving, removal, incorporation). The treatments without rye included were easier to plan and manage over the season. The rye –clover cover crop had the highest overall biomass but resulted in lowest yields regardless of cover crop management strategy. An sidedress N application increased performance of all cover crop combinations except the vetch only treatments, indicating N was limiting under all other management strategies. While cabbage yields were similar when cover crops were either planted in mixes or strips, the latter were easier to plant and manage.