Effect of postponing N application on soil N supply,plant N uptake and utilization in winter wheat

作者：Pei Xuexia, Xiu‐Bin Wang, Ping He, Xiuzhi Zhang, Kejiang Li, Wei Zhou, Guoqing Liang, Jiyun Jin · 发表于：Plant Nutrition and Fertilizing Science · 年份：2009 · 被引用次数：6 · 研究领域：Polymer-Based Agricultural Enhancements、Crop Yield and Soil Fertility

Field experiment was carried out to investigate postponing N application on soil N supply,plant N uptake and utilization in winter wheat.Results obtained showed that,compared with farmers' practice(N 300 kg/ha,1/2 basal and 1/2 topdressing at jointing stage,respectively),postponing N application treatment(N 210 kg/ha,1/3 basal,1/3 top- dressing at jointing stage and 1/3 topdressing at booting stage,respectively)improved N use efficiency greatly,and mini- mized apparent N losses without grain yield losses.Excessive N application(N 300 kg/ha)increased NO_3~--N content be- low 60 cm soil profile at different growth stage,which would result in high risk of NO3--N leaching into underground wa- ter.Postponing N application increased nitrate accumulation in the soil of 0-20 cm and reduced nitrate accumulation in 20-100 cm soil profile.Therefore it was concluded that postponing N application based on plant N uptake at different growth stage is a feasible N management practice,and nitrogen fertilizer could be saved by 30 % as compared with farm- ers' practice.