应用^(15)N示踪技术研究河南主要土类冬小麦对氮素的利用

STUDIES ON THE UTILIZATION OF NITROGEN BY WINTER WHEAT IN MAJOR SOILS OF HENAN PROVINCE

用１５Ｎ示踪方法研究了河南两种主要土类上冬小麦对施入氮素的利用、氮在土壤中的残留及损失。结果表明，除在潮土上全底肥处理的氮素利用率显著高于其它处理外，其余处理间均未达到显著水平。小麦根系的氮素利用率、小麦植株氮来自肥料的比例均是潮土高于砂姜黑土，表明了土类间的差异。总的来看，两种土类上，一次性施肥（全底肥与底耙肥处理）的土壤中氮残留量显著低于分次性施肥（底追肥与底追喷肥处理），并且每种施氮方法的残留量均为潮土大于砂姜黑土。不同土壤层次中残留氮分析表明，残留氮在０～２０ｃｍ土层中砂姜黑土为７６５％～９４２％，潮土为８８５％～９３７％。肥料氮的损失，其规律与土壤中氮的残留正好相反。

Utilization,retention and loss of fertilizer N by winter wheat were studied by using 15 N tracer technique in Shajiang black soil and Chao soil.Results showed that no significant difference at 5% LSD level was observed among five treatments on N utilizaiton rate except B treatment (all N applied as basal)in Chao soil.N utilization rate by wheat root in Chao soil was higher than that in Shajiang black soil.The amount of fertilizer N absorbed by wheat in Shajiang black soil was lower than that in Chao soil. In two soils,N retained rate with treatments B and B+P(2/3N as basal,1/3 as plough harrow)was obviously less than that with treatments B+T(2/3N as basal,1/3 as topdressing)and B+T+S(2/3 as basal,4/15 as topdressing and 1/15 as sprayed at flowering stage).In addition,N retetion rate of each treatment in Chao soil was more than that in Shajiang black soil.76 5%～94 2%of retained N was in soil top layer (0～20cm)in Shajiang black soil and 88 5%～93 7% in Chao soil.The N loss was negatively related to the retained N. \ \