Cover Crop Decomposition and Nutrient Cycling for Peanut.

Conservation tillage systems for peanut are gaining popularity in the southeastern U.S. because of reduced fuel costs and incidence of many diseases compared to conventional tillage.  An experiment was conducted to evaluate the decomposition of cover crops and supply of nutrients to the soil and subsequent peanut crop.  Soil and plant tissue samples of three different cover crops (wheat, rye, and crimson clover) plus vegetation and pods of peanuts at various stages of growth were analyzed for essential nutrients and biomass accumulation.  The greatest rate of deterioration occurred within 5 weeks of planting (17 May – 6 July 2008), with crimson clover (83%) decomposing more rapidly than rye or wheat (55% and 56%, respectively) during that span.  There was little decomposition of the cover crops for the next 11 weeks, followed by another rapid decomposition of cover crop residues during the final 2 weeks prior to peanut digging.  Biomass accumulation in peanut vegetation and pods were largest with a rye cover until 2 weeks before digging, but pods in wheat cover were greater just prior to digging.  At harvest, there was no difference in yield of peanut regardless of cover crop used.  The decomposition rate of cover crops varied between leguminous and grass crops, but did not impact final pod yield.