缺水与补水对小麦氮素吸收及土壤残留氮的影响

通过温室培养试验，研究了不同生长期缺水和补充灌水对冬小麦氮素吸收利用和土壤残留的影响．结果表明，在不同生长期缺水及分蘖期补充灌水均能显著降低冬小麦的氮素吸收，增加矿质态氮的土壤残留，土壤残留氮含量介于79．8～113．7mg·kg^-1；越冬、拔节、灌浆期补充灌水可显著提高冬小麦对土壤氮素的吸收能力，不同程度地降低氮素残留，土壤残留氮介于47．2～60．3mg·kg^-1．补充灌水引起的小麦吸氮能力提高与其对氮素的有效利用并不一致．越冬期补水，小麦籽粒吸氮量无显著变化；灌浆期补水，籽粒吸氮量相应提高20．9％；拔节期补水反而使籽粒吸氮量降低19．6％．

Influence of water deficit and supplemental irrigation on nitrogen uptake by winter wheat and nitrogen residual in soil

Pot experiment in greenhouse showed that water deficit at all growth stages and supplemental irrigation at tillering stage significantly decreased the nitrogen uptake by winter wheat and increased the mineral N residual (79.8-113.7 mg x kg(-1)) in soil. Supplemental irrigation at over-wintering, jointing or filling stage significantly increased the nitrogen uptake by plant and decreased the nitrogen residual (47.2-60.3 mg x kg(-1)) in soil. But, the increase of nitrogen uptake caused by supplemental irrigation did not always mean a high magnitude of efficient use of nitrogen by plants. Supplemental irrigation at over-wintering stage didn't induce any significant change in nitrogen content of grain, irrigation at filling stage increased the nitrogen content by 20.9%, and doing this at jointing stage decreased the nitrogen content by 19.6%, as compared to the control.