Accumulation of Late-Applied Nitrogen and Root Dynamics during Grain Filling in Irrigated Spring Wheat

Abstract

The objective of this study was to investigate the root growth and nitrogen (N) accumulation of spring wheat during grain filling under split N management. Two spring wheat genotypes were grown in a field with sandy loam soils at three levels of N fertilization (18, 21, and 24 g N m−2). Variations in N availability across soil depth were performed in additional experiments under controlled conditions in a greenhouse. The accumulations of total and late-applied N at maturity were 13% and 41% greater, respectively, for the genotype that had longer root length (+57%) and root-to-shoot ratio (+43%). The accumulation of 15N in the greenhouse study was 53% greater with 15N applied at a depth of 0.15 m than at a depth of 0.35 m. These results indicate that the genotype that accumulated more N was characterized by greater proliferation and maintenance of roots where N availability was greater.