用^(15)N示踪研究灌溉水平和氮磷配比对砂地小麦生长和氮素平衡的影响

Study on Effect of Wheat Growth and N Balance under Different Irrigation and Fertilizer Application Using ^(15)N Tracer

15N示踪研究证明，在不同灌溉水平下，在细质砂土上，增施磷肥可以大幅度提高小麦单位面积穗数、穗粒数和产量。并可以促进小麦对N素的吸收，提高肥料N利用率，降低肥料N损失率，促进营养物质的运输和转化，但是小麦的千粒重和含N量则随之下降。增施磷肥的效果大于增施N肥。在中等灌溉水平下，每公顷施纯N204kg，施P2O3180kg，可以实现砂地小麦高产高效的统一。

This study was carried out in fine sandy soil in Daming County of Hebei Provience from 1992~1993. By increasing irrigation times and adding P fertilizere in sandy soil, the growth and develop ment of tillering and secondary roots of wheat are promoted greatly, the grain yield of wheat and plant re covery of fertilizer N increased, the loss of fertilizer N decreased and the nutrient movement and transfor mation were stimulated plant responded to P fertilizer more significantly than to N fertilizer in fine sandy soil. The results also show that application of N at 204 kg·hm-2 and P2O5 at 180 kg·hm-2 could gain both high yield and high efficiency at middle irrigation level.