Cover Crops Influence Biomass Accumulation and Macronutrient Uptake By Corn.

Cover crops provide a sustainable method for capturing and recycling soil nutrients, which can be utilized by subsequent cash crops.  Nutrient uptake by plants is influenced by many factors, such as nutrient availability and mobility, biomass accumulation, and root growth and extension.  Research on the influence of cover crops on nutrient uptake by corn (Zea mays L.) in Arkansas is limited; therefore, the objective of this study was to evaluate the recovery of macronutrients by corn following cereal rye (Secale cereal) and tillage radish (Raphanus sativus L.) cover crops in Arkansas.  This study consisted of four cover crop treatments (tillage radish, cereal rye, tillage radish/cereal rye blend, and fallow).  Urea labeled with 2.5 atom % ¹⁵N was applied 2 weeks after cover crop planting at four N rates (0, 34, 67, and 101 kg N ha^-1) to assess the amount of fertilizer-N recovered by cover crops and corn.  Corn was no-till drilled into cover crop residue four weeks after cover crop termination and analyzed for ¹⁵N, total N, P, and K uptake at the V6 growth stage.  Corn biomass accumulation and total N, P, and K uptake were significantly greater following tillage radish than cereal rye, tillage radish/cereal rye blend, or fallow, regardless of N rate.  Mean corn uptake of total N, P, and K was 8, 9, and 13 times greater, respectively, following tillage radish than the lowest cover crop treatment, cereal rye.  More rapid decomposition of tillage radish residue compared to cereal rye likely contributed to increased biomass accumulation and macronutrient uptake by corn.  Based on results from this study, tillage radish is more effective than cereal rye and a tillage radish/cereal rye blend at recycling macronutrients for subsequent corn use in no-till systems in Arkansas over short time periods.