Effects of different N management modes on grain yield and quality as well as fertilizer N use efficiency of winter wheat

Chinese. 在高肥力条件下，研究了不同氮肥运筹模式对冬小麦籽粒产量、品质、氮肥利用率和土壤中硝态氮累积量的影响。结果表明，在本试验条件下，施用氮肥对籽粒产量、籽粒蛋白质含量和湿面筋含量无显著影响，而作为籽粒蛋白质质量指标的沉淀值、面团形成时间和面团稳定时间均明显改善。与分次施用（50％作底肥，50％作追肥）比较，拔节期一次全量追施。对籽粒蛋白质质量的改善效应更为显著，但其0～100cm土层中的硝态氮累积量也明显高于前者，增加了淋失和污染地下水的可能性。将施氮量由240kgN／hm. 降至168kgN／hm. 时，肥料利用率显著提高，0～100cm土层中的硝态氮累积量明显降低。因此，为兼顾提高产量、改善籽粒品质、提高肥料利用率和降低土壤中硝态氮的累积量等因素，可考虑在进一步降低施氮量的前提下，采取拔节期一次全量追施的施肥方式。

English. Both grain yield and quality can be improved through nitrogen （N） fertilization strategies, such as the rates and timings of N fertilization. Under N limiting soil condition, split application of N fertilizer （50% of total N fertilizer is applied at preplanting and the remainder at jointing） is known to increase grain yield and protein content and alter flour functionality. However, fewer studies are available on the effects of N fertilization on quality traits and nitrate N accumulation in the soil as well as N fertilizer use efficiency under N non-limiting soil condition, particular with all N fertilizer top-dressed at jointing. So the aim of present work was to assess the effects of different N management mode on the protein composition and dough rheological properties of wheat plant grown in the field with high fertility. The effect of N fertilization on N balance between wheat plant and soil and N fertilizer use efficiency was also determined with the aid of . 5N trace technique. It was found that N fertilizer had no effect on grain yield, protein content and wet gluten content（Table 2）, whereas those protein quality parameters such as sedimentation volume, dough developmental time and dough stability time were improved remarkably. Comparing with N split application treatments （50 % of total N fertilizer was applied at preplanting and the remainder at jointing）, all N fertilizer top-dressed at jointing led to significant increase of sedimentation volume, dough developmental time and dough stability time（Table 3）, while the nitrate nitrogen content （kg/ha） in the soil from 0 to 1130 cm was also increased significantly （Fig. 1 ）, which means raised possibility of leaching and polluting underground water. As the amount of N application decreased from 240 kg/ha to 168 kg/ha, fertilizer nitrogen use efficiency was raised obviously （Table 5 ） and nitrate nitrogen accumulation in the soil from 0 to 1130 cm was lessened （Fig. 1 ）.Therefore, for the sake of increasing grain yield, improving grain quality, enhancing fertilizer N use efficiency and reducing nitrate nitrogen content in the soil, it is proposed that all N fertilizer could be applied as topdressing at jointing with the amount less than 168 kg/ha.