Integration of summer and fall cover crops in vegetable cropping systems

Abstract

The demand for locally produced vegetables is growing in the Midwest, including Iowa. However, vegetables are a small fraction of total cropland in the state, and little research exists on approaches and techniques to increase the sustainability of vegetable production systems. Including cover crops in vegetable crop rotations can contribute to sustainability in vegetable cropping systems. This research investigated the integration of summer and fall cover crops in vegetable cropping systems to reduce weeds and nutrient leaching, improve soil chemical and biological properties, and enhance crop growth, yield, and produce quality. Cover crops studied in this research included buckwheat (Fagopyrum esculentum), cereal rye (Secale cereal), cowpea (Vigna unguiculata), crimson clover (Trifolium incarnatum), black oats (Avena strigosa), oilseed radish (Raphanus sativus var. oleifera), and sorghum-sudangrass (Sorghum bicolor ssp. drummondii). Effects of these cover crops were tested on fall production of cabbage (Brassica oleracea ‘Caraflex’) and lettuce (Lactuca sativa ‘Adriana’) and spring production of potato (Solanum tuberosum ‘Yukon Gold’ and ‘Red Pontiac’). In vegetable cropping systems, weeds have been traditionally managed through tillage or chemicals. With growing awareness and demand for sustainably grown produce, growers are interested in using weed control strategies that could provide environmental benefits. Two of the studies conducted as part of this research investigated effects of four cover crops (buckwheat, cowpea, black oats, and sorghum-sudangrass) on fall cabbage and lettuce production. Both studies were a split-plot randomized complete block design with cover crops as the whole plot and planting date of the vegetable as the subplot factor. Two planting dates were tested (immediately after or eight days after iv