Residual Maize Fertilizer Nitrogen Availability to Wheat on the Southeastern Coastal Plain

Abstract

AbstractIn southeastern Coastal Plain soils, little emphasis is placed on adjusting N fertilization of a crop based on the residual N left from the preceding crop because of the perception of coarse‐textured surface soils, winter rainfall in excess of evapotranspiration, and shallow‐rooted crops. However, estimates of annual water surplus do not include a winter crop, which may reduce NO3‐N leaching, nor consider current tillage practices, which enable deep rooting, and assimilation of subsoil NO3‐N. This study was conducted to determine the contribution of N applied to a maize (Zea mays L.) crop to the N supply of a subsequent winter wheat (Triticum aestivum L.) crop. Wheat was grown following maize fertilized with various rates of N and poultry litter on a Rains/Lynchburg sandy loam soil complex (fine‐loamy, siliceous, thermic Typic/Aeric Paleaquult) in 1990 and on a Noboco loamy sand (fine‐loamy, siliceous, thermic Typic Kandiudult) in 1991. Maize fertilizer N increased soil NO3‐N at the time of wheat planting. Residual N increased wheat dry matter, N content, and grain yield. An increase in maize N rate of 134 kg N ha−1 increased N supply to the subsequent wheat crop by approximately 15 kg ha−1 and increased wheat grain yield by 0.8 Mg ha−1. Poultry litter did not differ from fertilizer N in providing residual N to the wheat. This research demonstrates that previous crop fertilization rate may impact N supply to the subsequent crop, even on coarse‐textured Coastal Plain soils.