华北平原不同施氮量与施肥模式对作物产量与氮肥利用率的影响

合理施肥是保证作物高产、减少面源污染的重要措施，以华北平原为研究区域，基于7个长期施肥试验，探讨不同施氮量及施肥模式（不施肥CK、化肥NPK、有机肥M、有机无机配施NPKM）对作物产量及氮肥利用率的影响。结果表明，作物产量与施肥量之间整体呈抛物线趋势，作物产量最高值均出现在NPKM处理。不同施肥模式对作物产量有一定影响，NPKM与NPK处理小麦产量无显著差异，且显著高于M、CK处理；NPKM、NPK、M处理玉米产量无显著差异，均显著高于CK处理。氮肥利用率随着施氮量增加呈下降趋势，不同施肥模式对氮肥利用率有一定影响，小麦季NPKM与NPK处理氮肥利用率无显著差异，且高于M处理，玉米季NPKM、NPK、M处理之间氮肥利用率均无显著差异。综合分析施氮量与有机肥替代率两因素对小麦产量的影响，在华北平原，利用有机肥替代化肥潜力可观，且不会显著降低作物产量，甚至增产，但为避免显著减产，在考虑提高有机肥替代率时，需要满足总施氮量的需求。

Effects of nitrogen amount and fertilization patterns on crop yield and nitrogen use efficiency on the North China Plain

Appropriate fertilization is an important component for ensuring high crop yields and avoiding the disadvantages of non-point source pollution. We used the North China Plain as the study area and seven long-term experiments to investigate how different nitrogen application rates and fertilization modes (no fertilizer CK, fertilizer NPK, organic fertilizer M, organic-inorganic combined application NPKM) would affect crop yield and the efficient use of nitrogen. We found that there was a parabolic trend between crop yield and fertilization amount. The highest crop yield appeared in the combined application of organic and inorganic fertilizers and different fertilization modes affected crop yield. We found no significant difference between NPKM and NPK treatments for wheat yield, with both higher than with M and CK treatments. For maize crops, there was no significant difference in crop yield between NPKM, NPK and M although they had significantly higher yields than with CK treatment. The nitrogen utilization rate decreased with higher nitrogen application and fertilization modes had certain effects on nitrogen utilization rates. We found no significant difference in nitrogen use efficiency between NPKM and NPK treatment for wheat, but they were higher than with M treatment. There was no significant difference in nitrogen use efficiency between NPKM, NPK and M for maize. This comprehensive analysis of the effects of nitrogen application rate and fertilizer replacement ratio on wheat yield showed that, in the North China Plain, there was great potential to replace chemical fertilizers with organic fertilizers. This replacement would not significantly decrease crop yields, and possibly led to higher yields than with purified fertilizer. However, in order to avoid a significant decrease in crop yields, total N input should be determined when replacing chemical fertilizer with organic fertilizer.