中文摘要：

【目的】针对河西地区水资源短缺、作物水肥利用效率低等问题,研究滴灌施肥条件下生育期土壤水分调控对河西地区春小麦氮素吸收和利用的影响,以期探索提高氮肥利用效率的土壤水分调控模式。【方法】以春小麦‘永良4号’为试验材料进行田间小区试验,根据前期的滴灌施肥试验,施氮量为N 180 kg/hm2,在春小麦生育期设置5个土壤水分下限（W1、W2、W3、W4和CK）控制水平,研究生育期土壤水分调控对河西地区滴灌春小麦氮素吸收、分配和转运及根区土壤硝态氮含量的影响。【结果】1）一定的施肥水平下,土壤水分下限的增长会增加各处理小麦的生育期总灌水量,以充分灌溉（CK）处理最大,分别比W1、W2、W3、W4处理高26.6%、15.0%、9.3%和4.8%。2）灌水量的增加会促进小麦植株对土壤养分的吸收同化,与W4处理相比,W1、W2、W3处理的氮素吸收量分别显著减少29.3%、23.0%和15.5%,CK与W4处理差异不显著（P〉0.05）。3）成熟期各处理小麦营养器官中氮素吸收量以CK处理最大,分别比W1、W2、W3、W4处理高28.2%、28.6%、19.2%和12.7%,但其子粒中的氮素吸收量比W4处理显著低10.4%。开花期后营养器官中的氮素向子粒的转移量和转移率均以W4处理最大,分别比W1、W2、W3、CK处理显著增加40.4%、28.0%、10.6%、10.0%和6.8%、3.5%、1.3%、6.9%,但W4处理小麦氮素转移量对子粒的贡献率最小（76.2%）。随着土壤水分下限的增加,各处理氮素吸收效率、氮素生产效率及氮素收获指数呈先增加后减小的变化趋势,均在W4处理下获得最大值。4）在一定施肥水平下,灌水量的增加会加大硝态氮向土壤深处运移,不利于小麦植株对土壤硝态氮的吸收利用。5）生育期土壤水分调控对小麦根区土壤硝态氮含量有显著性影响,成熟期0—100 cm土层内土壤硝态氮累积量以W4处理最小,分别比W1、W2、W3和对照（CK）处理减少9

英文摘要：

[ Objectives ] In Hexi Region of Gansu Province, there is shortage of water resource, and the water and fertilizer use efficiencies of crops are low. The nitrogen uptake and utilization of spring wheat was studied, to find the effective regulation mode of soil water at different growing stages of spring wheat. [ Methods ] Field experiments were carried out with the spring wheat cultivar of ＇Yongliang 4＇ as materials at a nitrogen application rate of N 180 kg/hm2. Five lower soil water supply treatments, recorded as W1, W2, W3, W4 and CK（sufficient irrigation） were set up at the four growing stages of spring wheat. The accumulation, distribution and translocation of nitrogen in spring wheat were determined, and the rhizosphere soil NO3--N contents were analyzed at the same time. [ Results ] 1） When the low soil water limit became high, the irrigation amount of spring wheat would be increased, and the increment in CK was significantly higher than in W1, W2, W3 and W4 treatments, with the corresponding increase of 26.6%, 15.0%, 9.3% and 4.8%, respectively. 2） Increased irrigation promoted the soil nutrient assimilation by wheat plants. Compared with W4 treatment, the nitrogen assimilation of wheat was significantly reduced by 29.3%, 23.0% and 15.5% in the W1, W2 and W3 treatments, respectively, while the difference was not significant between the W4 and CK. 3） Compared with the W1, W2, W3 and W4 treatments, the nitrogen assimilation in vegetative organs of the CK treatment at the maturity was increased by 28.2%, 28.6%, 19.2% and 12.7%, respectively, while the grain nitrogen assimilation of the CK treatment was significantly reduced by 10.4% compared with the W4 treatment. The W4 had the highest nitrogen translocation amount and efficiency except for its decreasing contribution proportion （76.2%）. Compared with the W1, W2, W3 and CK treatments, the nitrogen translocation amount and efficiency were increased by 40.4%, 28.0%, 10.6%, 10.0% and 6.8%, 3.5%, 1.3%, 6.9%, respectively. With the increase of