太湖流域施氮量对小麦 土壤系统氮素利用的影响

为给南方麦区小麦合理施氮提供理论依据，在太湖流域典型地区的两年3季稻麦施肥量定位试验基础上，研究了施氮量与小麦产量、小麦吸氮量、土壤剖面无机氮素含量的关系。结果表明，随着施氮量的增加，小麦的产量、干物质积累量和氮素积累量都呈增大趋势，而氮肥的表观利用率、生理利用效率和农学利用效率都减小，施氮量225~300 kg·hm-2是小麦高产、氮相对高效的适宜施氮量。小麦不同生育时期土壤剖面无机氮素主要集中在0~30 cm土层，且随着施氮量增加而增加。30~100 cm土层无机氮素对施氮量300~375 kg·hm-2有明显的响应，拔节期以后已有明显的淋溶现象。施氮量300~375 kg·hm-2土壤中无机氮素的残留量一直较高，小麦成熟期土壤无机氮量与播种前的相比，除施氮量375 kg·hm-2处理仍在增加外，施氮量小于300 kg·hm-2的处理均有所减少。小麦土壤系统氮素表观损失量随着施氮量的增加而增大，施氮处理75和375 kg·hm-2的损失量分别为26.20和168.64 kg·hm-2，损失率（占相应的施氮量）分别为34.93％和44.97％。施氮量225 kg·hm-2是本地区小麦生态安全的临界施氮量。

Effects of Nitrogen Application Rate on Nitrogen Utilization of Wheat Soil System in Taihu Lake Region

Taihu Lake region is one of the most high yield agriculture areas of China,the nitrogen application rate in the farm land is always higher.In order to find out the effects of nitrogen application rate(NAR) on wheat and the inorganic nitrogen in soil profile(INISP) of southern China wheat region,the optimal nitrogen application rate and the located nitrogen fertilizer experiment in the rotation of rice and wheat were studied in the experiment station of Farming and Forestry Bureau of Wujiang County,Suzhou ci...