氮磷钾配施对小麦植株养分吸收利用和产量的影响

采用大田试验,研究了不同氮水平与磷、钾配施对小麦植株氮磷钾含量、土壤速效氮磷钾含量和产量的影响。结果表明,在低氮（135kg N/hm ²）、中氮（225kg N/hm ²）和高氮（315kg N/hm ²）与2个磷钾用量（P₂O₅-K₂O,90-120、135-180kg/hm ²）处理组合中,各处理不同生育时期植株干重、氮钾含量、氮钾累积量随供氮水平提高而增高;等氮条件下,增施磷钾使植株含氮量降低,植株氮、磷和钾累积量随磷钾用量增加而增多。各施肥处理生育期间土壤碱解氮含量呈波动性变化,表现为起身期较冬前降低,起身至开花期不断增高,开花期至灌浆期明显下降,灌浆期至成熟期有所回升的特征。随生育进程,各处理土壤速效磷含量不断降低,土壤速效钾含量呈“V”字形变化,在开花期达到谷底。高氮水平各生育时期的土壤速效磷、钾含量低于低氮处理;等氮水平下增施磷、钾肥处理的土壤速效磷、钾含量提高。单位面积穗数随供氮增多而增加,穗粒数和千粒重以中氮处理最高;产量表现与穗数相似,但中、高氮处理差异较小。等氮水平下,增施磷钾可明显改善各产量构成因素和产量。随供氮增多,单位氮素生产子粒能力降低,氮肥利用率下降;单位磷、钾素生产子粒能力随氮素用量增多呈低—高—低变化。研究表明,中氮（225kg N/hm ²）配施磷钾（P₂O₅-K₂O,90-120kg/hm ²或135-180kg/hm ²）有利于调节生育期间土壤养分供应,改善植株养分吸收、干物质生产和产量形成能力。

Effects of Coordinately Application of N,P, and K on Nutrient Contents in Plants and Soils and Wheat Yield

In this study, the effects of coordinately application of nitrogen (N), phosphorus (P), and potassium (K) on nutrient contents in plants and soils as well as yield in wheat were investigated under field conditions. Results indicated that among the treatments covering three N levels (i.e., low N with 135kg N/hm ², medium N with 225kg N/hm ², and high N with 315kg N/hm ²) and two levels of P and K amounts (i.e., P₂O₅-K₂O 90-120kg/hm ² and P₂O₅-K₂O 135-180kg/hm ²),the plant biomass, concentrations and accumulative amounts of N and K were increased along with the elevated N levels. Under the equal N condition, the treatments with more P and K exhibited lowered N concentrations in plants whereas the accumulative amounts of N, P, and K were elevated with the increase of P and K amounts. The N available contents in soils at various growth stages across the nutrient treatments exhibited a fluctuating pattern, showing decreases at erection stage relative to before winter, gradually elevation from erection stage to flowering stage, decline from flowering to filling stage, and re-rising from filling to the maturity stage. Along with growth progression, the available P contents in soils gradually reduced whereas the soil available K contents changed in a "V" style pattern that was the lowest at flowering stage. Meanwhile, the available contents of P and K at various growth stages under high N level condition were lower than those under lower N level condition. Under the equal N condition, the available contents of P and K in soils were increased in treatments supplemented with more P and K amounts. The spike numbers per unit was elevated with the increased N whereas the kernel numbers per spike and 1000-grain weight reached the peaks at medium N condition. The yields were similar to spike numbers, but relatively little variation observed between the treatments of medium N and high N. At equal N condition, the treatments with increased P and K drastically improved the yield components and yields. Along with increase of the N levels, the grain production capacity per N unit whereas the grain production capacity per unit of P and K exhibited a low-high-low pattern. These results indicate that the medium N treatment (225kg N/hm ²) together with coordinately application of P and K (P₂O₅-K₂O 90-120kg/hm ²and P₂O₅-K₂O 135-180kg/hm ²) can positively regulate the nutrient supply in soils by which to improve the plant nutrient uptake, biomass production, and yield formation.