中文摘要：

为给我国黄淮海平原冬小麦生产氮肥合理施用提供理论依据,于2015—2016年小麦生长季,以山农8355和济麦22为材料,设置4个氮肥基追比处理（T1：不施氮;T2、T3、T4施氮量均为240 kg·hm^-2,基追比依次为7∶3、5∶5、3∶7）,研究氮肥不同基追比对冬小麦土壤硝态氮时空分布、小麦各生育时期氮素盈亏及氮素利用的影响。结果表明,在总施氮量相同条件下,T2处理增加了小麦生育前期硝态氮向深层土壤的淋洗,小麦生育后期0-60 cm土层中硝态氮积累量降低,导致小麦生育后期（需氮高峰期）土壤氮素供应不足;T4处理显著降低小麦生育前期氮素总盈余量,减少小麦生育后期氮素的亏缺,氮素的利用效率和籽粒产量（山农8355为9 399 kg·hm^-2,济麦22为9 572 kg·hm^-2）均达到最高。本试验条件下,氮肥基追比3∶7是兼顾高产和高氮肥利用效率的最优处理。

英文摘要：

In order to provide theory basis for reasonable application of nitrogen fertilizer in winter wheat production in the Huang-Huai-Hai plain of China,the effects of different nitrogen fertilizer topdressing ratios on time-space distribution of soil NO_3--N,apparent budget of soil nitrogen and nitrogen use efficiency in various growth stages of winter wheat were studied with Shannong 8355 and Jimai 22 as materials. The study were conducted in wheat growing season during 2015 - 2016,and four nitrogen treatments（ without applying N fertilizer（ T1）; N application rate of 240 kg·hm^-2 with topdressing ratio as 7∶ 3（ T2）,5∶ 5（ T3） and 3∶ 7（ T4）） were set up. The results showed that under the same nitrogen application rate condition,the NO_3--N content in deep soil layers of T2 treatment in early growth stage was increased,so the NO_3--N content was reduced in 0 - 60-cm soil layers at late growth stage,which could not meet the needs of wheat for nitrogen.The surplus amount of soil nitrogen of T4 treatment was significantly reduced in early growth stage,which reduced the nitrogen deficiency at late growth stage,and the nitrogen use efficiency and grain yield（ Shannong8335 of 9 399 kg·hm-2,Jimai 22 of 9 572 kg·hm^-2） of winter wheat both showed the highest value. Inconclusion,the most appropriate nitrogen fertilizer topdressing ratio treatment was T4 treatment with the ratio as 3∶ 7 which gave consideration to high yield and high nitrogen use efficiency.