施氮量和底追比例对小麦氮素利用和土壤硝态氮含量的影响

Effects of Nitrogen Application Rate and Ratio of Base and Topdressing on Nitrogen Utilization and Soil NO_3-N Content in Winter Wheat

利用^15N同位素示踪技术研究了不同的施氮量和底追比例对小麦氮素利用和土壤硝态氮的影响。结果表明：底追比例均为5：5，处理2（纯氮施用量为168kg／hm^2）与处理1（纯氮施用量为240kg／hm^2）比较，处理2成熟期植株中土壤氮素的积累量，肥料氮的利用率均高于处理1的，但处理2的土壤硝态氮含量低；籽粒产量、蛋白质含量、湿面筋含量和面团稳定时间处理间无显著差异。纯氮施用量均为168kg／hm^2，氮肥全部用于拔节期追施的处理3与处理2比较，处理3成熟期植株中土壤氮素的积累量，籽粒蛋白质含量、面团稳定时间和0～40cm土层土壤硝态氮的含量均高于处理2的；肥料氮的利用率和籽粒产量处理间无显著差异。成熟期不同处理0～60cm土层土壤硝态氮含量均低于播种前，在60～80cm土层形成累积峰并高于播种前，但80cm以下层次与播前相比无明显差异。

Effects of different nitrogen application rate and ratio of base and topdressing on nitrogen utilization and soil NO3-N content in winter wheat were studied by using I;N isotope technique. The results indicated that： Under the same proportion of 5 ： 5, nitrogen accumulation amount derived from soil, and N use efficiency of treatment 2 （168 kg N/hm^2） were higher than those of treatment 1 （240 kg N/hm^2）, but soil NO3-N content of treatment 2 was lower than that of treatment 1. Grain yield, protein content,wet gluten content and dough stability time had no significant difference between the two treatments. Under the same nitrogen application rate of 168 kg/hm^2, nitrogen amount derived from soil was raised with the proportion increasing of topdressing of nitrogen, so did the protein content, dough stability time and soil NO3-N content at the layers of 0-40 cm, but the N use efficiency and grain yield had no significant difference between the two treatments. At maturity stage, soil NO3-N content at the layers of 0-60 cm were higher than that of before planting, there was a soil NO3-N accumulation peak at the layer of 60;80 cm and the soil NO3-N content was higher than that of before planting, but there was no significant difference under 80 cm.