施氮量和底追比例对小麦氮素吸收利用及子粒产量和蛋白质含量的影响

在大田栽培条件下,运用15N示踪技术研究了不同施氮量和底追肥比例对小麦氮素利用和子粒产量及蛋白质含量的影响。结果表明,施用氮肥提高了小麦植株的氮素积累量、子粒产量、蛋白质含量和蛋白质产量。相同施氮量条件下增加追肥氮的比例,提高了氮肥农学利用率和吸收利用率,增加了植株地上部器官(子粒+营养器官)中追肥氮、土壤氮的积累量,提高了营养器官中氮素的转运量和开花后氮素的同化量,增加了子粒蛋白质含量。相同的氮素底追肥比例条件下,将240.kg/hm2施氮量降至168.kg/hm2的处理,氮肥农学利用率、氮肥吸收利用率、氮肥偏生产力提高,子粒中土壤氮的积累量增加,植株地上部器官中土壤氮的积累量亦增加,开花后氮素同化量提高,子粒蛋白质含量增加。各施氮处理间子粒产量无显著差异。在本试验条件下,施氮量为168.kg/hm2且全部于拔节期追施是兼顾产量、品质和效益的优化处理。

Effects of nitrogen application rate and ratio of base and topdressing on nitrogen absorption, utilization, grain yield, and grain protein content in winter wheat

Field experiments were conducted to study effects of nitrogen application rate and ratio of base and topdressing on nitrogen utilization,grain yield, and grain protein content in winter wheat using()~(15)N tracer technique. Results showed that using nitrogen increased nitrogen cumulate,grain yield,protein content,and grain protein yield.Under the same nitrogen application rate,higher topdressing ratio improved nitrogen agronomic efficiency,nitrogen recovery efficiency,increased accumulation amount of topdressing fertilizer nitrogen and soil nitrogen in above-ground part(nutrition part kernel),and improved transferring amount from nutrition part to kernel,assimilating amount after anthesis,and protein content.Under the same ratio of base and topdressing,decreasing nitrogen application rate from 240 kg/ha to 168 kg/ha increased nitrogen agronomic efficiency,nitrogen recovery efficiency,and nitrogen partial factor productivity,meanwhile,accumulation amount of soil nitrogen in kernel,accumulation amount of soil nitrogen in above-ground part,and assimilating amount after anthesis and protein content were improved as well.Grain yields had no statistical significant difference among different nitrogen application treatments.Under the field fertility of this experiment,one time application of 168 kg/ha nitrogen at jointing stage,was the optimal treatment taking account of yield,quality,and benefit.