Nitrogen Assimilation and Biomass Yield of Winter Cover Crops Used in Sustainable Horticultural Crop Production

Abstract

Cover crops are planted during winter to prevent soil erosion, improve soil quality, and supply nutrients to the subsequent spring crops. In a 2-year study, three winter cover crops were compared for their nitrogen assimilation and biomass yielding ability. The experimental design was randomized complete block replicated four times with cereal rye, hairy vetch, crimson clover, and a fallow control comprising the treatments. Cover crop roots were well distributed from 1 to 50 cm of soil depth and increased from fall to spring as temperature increased. There was greater reduction in soil inorganic N during fall and winter in cover crop plots compared to control. Early season soil NO–3 concentration was lower in rye than crimson clover or hairy vetch. The amount of N assimilated by hairy vetch and crimson clover was significantly greater than cereal rye or control. There was no difference in the biomass yield of the three cover crops during the first year, but cereal rye and crimson clover produced significantly greater biomass than hairy vetch during the second year. The results suggest that cereal rye is more suited for preventing leaching of residual N from the preceding summer crop, while the two legumes can supply more N to the following crop.