【摘要】 在冬小麦施氮144 kg/hm2的基础上,研究了夏玉米4个施氮量(0,90,180,270和360 kg/hm2)对后茬冬小麦生长期间土壤硝态氮含量变化、无机氮供应以及小麦氮素吸收与利用的影响。结果表明:与玉米不施氮(简称不施氮)相比,玉米施氮(简称施氮)0~200 cm土壤硝态氮含量在冬小麦生长期间显著增加,自冬小麦拔节起,0~40,0~130和0~200 cm 3层深的土壤硝态氮含量均随着玉米施氮量(简称施氮量)的增加而明显递增;与冬小麦播种时相比,不施氮0~130 cm土壤无机氮减少156 kg/hm2,施氮90 kg/hm2该层土壤无机氮富积41 kg/hm2,且富积量随着施氮量继续增加而递增;随着施氮量增加,冬小麦收获时的植株吸氮量和子粒氮素积累量均增加;当施氮量低于180 kg/hm2时,植物氮素积累量在不同施氮量之间无显著差异;当施氮量低于270 kg/hm2时,不同施氮量的子粒氮素积累量差异不明显。在本试验条件下,冬小麦子粒氮肥利用率随着施氮量增加而递增,但差异不显著。更多还原

【Abstract】 To better understand the optional N application of summer maize,field experiment with the summer maize-winter wheat rotation was carried out in Huang-huai-hai Plain in 2002-2003.Four rates of nitrogen fertilizer(i.e.0,90,180,270 and 360 kg/ha) were applied to maize with high-yield hybrid Zhengdan 958 and the population of 9 plants per square meter.The following crop is winter wheat with cultivar 97-3 and seed rate of 704 grain per square meter.N rate of 144 kg/ha was applied at wheat sowing.With exception of the precipitation of 112.1 mm during wheat season,two times of irrigation with 75 mm at each time were used on April 13 and May 9,2003,respectively.The influences of maize N rates on soil inorganic N dynamics during wheat season and wheat N utilization were examined.The results are as follows:In comparison with zero N applied to maize(ZN),N applied to maize significantly increases the content of 0-200 cm soil nitrate during wheat season.The nitrate contents in the 0-40,0-130 and 0-200 cm soil profiles all apparently ascend with N rate increment from wheat shooting to maturity.The amount of 0-130 cm soil inorganic N in ZN plot decreases by 156 kg/ha during wheat season. However,that in the N rate of 90 kg/ha plot increases by 41 kg/ha at the same period,and the amount of soil inorganic N continually increases with the N rate increment during wheat season.At wheat maturity,The amount of plant N and that of grain N both increase with the increment of N rate.The amount of plant N has no significant differences between N rates when N rate is no more than 180 kg/ha.There is also no apparent differences of the grain N amount between N rates when N rate is no more than 270 kg/ha.In this experiment,the wheat grain NUE is just 0.2%-2.9%.更多还原