黄土高原塬区旱地长期施肥对小麦产量的影响

以18年长期肥料定位试验为背景，研究了长期施肥条件下小麦的增产效应18年单施氮肥平均增产418．1kg·hm^-2，增产率达28．4％，其中干旱年减产率为13．9％，常态年、丰水年增产率达30．3％、58．9％；单施磷肥平均减产率为9．3％，干旱年增产率达6．5％，常态年、丰水年减产率为15．4％、10．0％；有机肥平均增产率达82．8％；NP、PM、NM、NPM平均增产率分别达127．8％、118．9％、144．4％，169．3％，不同降水年型施肥对小麦的产量结构影响不同，普遍表现为干旱年成穗数、穗粒数、千粒重减少，丰水年增加，不同降水年型穗粒数、成穗数、千粒重的变化是不同施肥处理对小麦产量结构的调控措施。

Effects of long-term fertilization on wheat yield on Loess Plateau

The effect of long-term fertilization on the yield of winter wheat was studied on the basis of 18-year located experiment on the Loess Plateau. The results showed that the winter wheat yield increased 418.1 kg.hm-2 under N fertilization, and the average increasing rate was different with precipitation. In average and rain rich year, the average increasing rate were 30.3% and 58.9%, respectively, but in drought year, the yield decreased, and its average decreasing rate was 13.9%. The winter wheat yield under P fertilizer increased in drought year, and decreased in average and rain rich year. The average increasing rate was 6.5% in drought year, and the average decreasing rate was 15.4% and 10.0%, respectively. The average increasing rate in M, NP, PM, NM and NPM was 82.8%, 127.8%, 18.9%, 144.4%, and 169.3%, respectively. In addition, precipitation affected the amount of spike, grains per spike, and weight of thousand-grains.