Contribution and fate of maize residue-15N and urea-15N as affected by N fertilization regime.

ABSTRACT: Increasing amounts of crop residues are being returned to croplands. Understanding nitrogen (N) availability in crop residues under various N fertilization regimes is important in optimizing N management. Pot experiments were conducted to investigate the contribution, fate and residual effects of urea and maize residue-N using a 15N isotope technique. Four N regimes were tested: three basal-topdressing ratios of N applied as urea (100-0, 75-25, 50-50) and one basal application of 75% N as urea and 25% N as manure (75U+25M). An average of 31.4% wheat N uptake was derived from urea, 9.2% from maize residue, and 59.5% from the soil in the first season. During the growing stages of wheat, maize residue contributed 0.3-4.8% and 3.1-13.2% to soil mineral and microbial biomass N, respectively, an

SUBMITTER: Ding W 

PROVIDER: S-EPMC6324797 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature