灌溉施肥对冬小麦土壤氮素盈亏的影响

通过田间小区试验，研究了灌溉和施肥对冬小麦生育期间0～400cm土壤硝态氮累积、移动特征及小麦产量的影响，并对0～200cm土壤氮素的盈亏、氮肥利用率、残留率及损失率进行了表观估算，旨在为小麦的氮素利用与推荐施肥提供理论依据。结果表明，0-400cm硝态氮累积量随着施氮量的增加而显著增加。施氮量对0～100cm土体硝态氮累积量有显著影响，施氮与灌水对200cm以下土壤中的硝态氮累积都有影响，同时水氮交互作用不容忽视。施氮并结合灌水可以显著提高冬小麦籽粒产量，施氮而不灌水也有一定的增产作用。0～200cm土壤氮素的表现盈余主要出现在小麦拔节～灌策期间，表观亏缺主要在播种～拔节期及灌策～收获期。相同灌水量下，氮肥利用率随施氮量的增加显著降低，而损失率增加。施氮130kg／hm^2、灌水60mm处理的氮肥利用率最大，为25．7％。从硝态氮累积量、产量及氮肥利用率等方面考虑，本试验比较合理的肥水配比应为施氮130kg／hm^2，灌水60mm。

Effect of N Fertilizer and Irrigation on Apparent Budget of Soil N in Winter Wheat in Anthrosol

A field experiment was carried out to study the effect of different irrigation and N rates on nitrate-N movement and accumulation in soil profile and grain yield of winter wheat. At the same time, the apparent budget of soil N, apparent N recovery, residual and losses rate in 0-400 cm soil were investigated. The results indicated that nitrate-N accumulation increased significantly in 0-400 soil profile with N rates increasing. N application significantly influenced the nitrate-N accumulation in 0-100 cm soil profile, either fertilization or irrigation could influence nitrate-N accumulation in 200-400 cm soil profile, and the interaction between them could not be neglected. Combination of fertilization and irrigation may significantly increased grain yield of winter wheat, fertilization without irrigation could also increased grain yield. Soil N of 0-200 cm was surplus from elongation to filling stage, and deficient from sowing to elongation and filling to harvesting. Under the same irrigation rate, apparent N recovery decreased significantly with N rates increasing, while losses rate increased. The highest fertilizer N recovery was 25.7% in the treatment of N rates of 130 kg/hm^2 and irrigation of 60 mm. In view of nitrate-N accumulation, grain yield and fertilizer N recovery, the reasonable rate of N and irrigation was N 130 kg/hm^2 with irrigation 60 mm.