施氮量对小麦氮磷钾养分吸收利用和产量的影响

高产条件下研究了不同施氮量对小麦植株氮、磷、钾养分吸收利用及籽粒产量的影响.结果表明,适量施氮可促进小麦植株对氮素的吸收与积累,较高的施氮量不利于起身期之后的氮素积累,致使成熟期小麦氮素积累量未能显著提高;与不施氮肥相比,施氮显著提高植株磷素积累量;随施氮量增加,植株磷素积累量增加不显著;施氮量增加促进小麦生育前期对钾素的吸收积累,在生育后期降低植株钾素的流失.随施氮量增加,籽粒氮素含量呈先增后降的趋势,氮素向籽粒的分配比例趋于降低,植株氮素利用效率无显著变化,氮素收获指数下降;不同施氮处理之间籽粒磷素含量和钾素含量无显著差异,施氮量增加,营养器官钾素含量、钾素积累量和钾素向叶片的分配比例均呈增加趋势;同时,磷素和钾素利用效率降低;不同施氮处理间,植株磷素、钾素收获指数无显著差异.籽粒产量随施氮量增加呈先增加后降低的趋势,以施氮195 kg/hm2的处理籽粒产量最高.

Effects of Different Nitrogen Rates of Fertilization on Nitrogen, Phosphorous and Potassium Uptakes and Utilizations as well as Kernel Yield of Wheat under High-yield Circumstances

The effects of different nitrogen rates of fertilization on nitrogen,phosphorous and potassium uptakes and utilizations as well as kernel yield of wheat were studied under high-yield circumstance and the results indicated that proper nitrogen rates of fertilization could help wheat plants to take up and accumulate nitrogen and high nitrogen rates of fertilization were detrimental to the nitrogen accumulation after the erecton of wheat leaves so that the accumulative nitrogen amount of wheat plants did not significantly increased at the maturing stage.Compared with non-nitrogen fertilization,nitrogen fertilization significantly in creased phosphorous accumulation in wheat plants;the phosphorous accumulation did not significantly increased as the nitrogen rates of fertilization increawed.Increased nitrogen rates of fertilization helped wheat absorb and accumulate potassium in early wheat growth and reduced potassium loss of wheat plants in late wheat growth.As the nitrogen rates of fertilizations increased,the content of kernel nitrogen appeared to first increase and then decline,the proportion of allocated nitrogen to the kernels tended to decline,the nitrogen use efficiencies of the plants did not significantly changed and the nitrogen harvest index decreased.The contents of kernel phosphorous and potassium did not significantly differed among different nitrogen rates of fertilization,and potassium contents and accumulative potassium amount of the vegetative parts and the proportion of allocated potassium to the leaves all appeared to increase;in the meantime,the phosphorous and potassium use efficiencies declined.Among different nitrogen rates of fertilization,the phosphorous and potassium harvest indexes did not significantly differ.As the nitrogen rates of fertilization increased,the kernel yield appeared to incease first and then decline with its peak occurring at 195 kg/hm~2 nitrogen of fertilization.