摘要：

为了解决宁夏旱地糜子生育前期大量氮素流失的面源污染和生育后期土壤氮肥供应不足,导致植株早衰和减产等问题。在施氮量135 kg/hm²水平下,根据基肥∶拔节肥∶穗肥的比例设计了5个氮肥运筹处理,基肥∶拔节肥∶穗肥的比例分别为6∶2∶2(N1,氮肥前置)、6∶0∶4(N2,常规氮肥运筹)、2∶4∶4(N3,前氮后移)、4∶6∶0(N4,前氮后移)、4∶0∶6(N5,前氮后移)、不施氮肥处理(CK),通过研究氮肥后移对糜子干物质积累、籽粒产量及氮素吸收利用效率的影响,旨在探索糜子最佳的氮肥施用时期和施用量。结果表明,不同生育期内氮肥运筹对糜子干物质积累、籽粒产量及其构成因素、氮肥利用效率的影响达到显著差异,均显著高于CK。各处理籽粒产量分别比CK增加了18.9%,26.6%,30.8%,22.1%,23.3%;各处理氮素积累量表现为穗>茎>叶>根,且显著高于CK。氮肥利用效率均显著高于CK,氮肥后移处理(N3、N4、N5)比氮肥前置处理(N1)依次提高了4.75,3.08,2.99百分点。基于主成分和相关性分析,得出N3(基肥∶拔节肥∶抽穗肥比例为2∶4∶4)为宁南山区糜子生产最佳氮肥后移方案,适宜的氮肥后移可促进糜子干物质和氮素的积累与转运,有利于改善生育后期糜子叶片的氮素代谢,延缓了叶片的衰老,提高糜子产量。

关键词: 糜子, 氮肥后移, 产量, 氮肥利用率, 氮素吸收

Abstract:

In order to solve the problems of non-point source pollution caused by a large amount of nitrogen loss in the early growth stage and insufficient nitrogen supply in the late growth stage of dry land millet in Ningxia,which led to premature senescence and yield reduction.Under the nitrogen application rate of 135 kg/ha,five nitrogen treatments were designed according to the ratio of base fertilizer∶jointing fertilizer∶ear fertilizer.The ratio of base fertilizer∶jointing fertilizer∶ear fertilizer was 6∶2∶2(N1,nitrogen fertilizer was in front),6∶0∶4(N2,conventional nitrogen management),2∶4∶4(N3,the front nitrogen moves backward),4∶6∶0(N4,front nitrogen moved back),4∶0∶6(N5,nitrogen from front to back),no nitrogen fertilizer treatment(CK).The effects of nitrogen fertilizer backward movement on dry matter accumulation,grain yield and nitrogen absorption and utilization efficiency of broomcorn millet were studied.The purpose of this paper was to explore the best nitrogen application period and amount of broomcorn millet.The effects of nitrogen application on dry matter accumulation,grain yield and its components,and nitrogen use efficiency of broomcorn millet in different growth stages were significantly different,and all of them were significantly higher than CK.The effects on grain yield and its components of broomcorn millet were significantly higher than that of CK,and the grain yield of each treatment increased 18.9%,26.6%,30.8%,22.1% and 23.3% compared with CK,respectively.Nitrogen accumulation of each treatment showed spike>stems>leaf>root,and significantly higher than CK.N use efficiency was significantly higher than CK,and N backward treatment(N3,N4,N5)increased by 4.75,3.08 and 2.99 percent points,respectively,compared with nitrogen pre-treatment(N1).Based on principal component analysis and correlation analysis,N3(base fertilizer∶jointing fertilizer∶heading fertilizer ratio of 2∶4∶4)was the best plan for the backward transfer of nitrogen fertilizer in broomcorn millet production in the mountainous area of Southern Ningxia.The appropriate delayed nitrogen transfer could promote the accumulation and transport of dry matter and nitrogen,improve the nitrogen metabolism of broomcorn millet leaves at the late growth stage,delay leaf senescence,and improve the yield of broomcorn millet.

Key words: Millet, Postponed nitrogen application, Yield, Nitrogen use efficiency, Nitrogen absorption