N肥深施深度对小麦吸收利用N的影响

本文应用＾１５Ｎ示踪技术，在川中紫色土上进行了聚土的表层施肥（施肥深度１－２ｃｍ）、中层施肥（深施２５ｃｍ）、底层施肥（深施４５ｃｍ）和平作表层施肥不同处理小麦吸Ｎ特性等的研究。结果表明：Ｎ肥利用率是“平＋表施”〉“聚＋底施”〉“聚＋中施”〉“聚＋表施”，处理间Ｎ肥利用率最高是２３．７８％，小麦一生有３８．７－４４．１％的Ｎ来自肥料。小麦拔节以前无论是聚土还是平作，其表层施肥地上部分ＮＤＦＦ值极显

EFFECT OF N APPLICATION DEPTHS ON ABSORPTION AND UTILIZATION OF NITROGEN BY WHEAT

By means of ¹⁵N tracer technigue, the nitrogen absorption of wheat in different ways of soil fertility improvement was studied in purple soils of the Sichuan Basin. The results indicated that the utilization rates of different treatments were in the order of ordinary cultivation with surface layer fertilization (the fertilization depth of 1-2cm) >cultivation by gathering soil with deep layer fertilization (45cm) >cultivation by gathering soil with subsurface layer fertilization (25cm) >cultivation by gathering soil with surface layer fertilization(1-2cm), in which the most high rate was up to 23.78%, and 38.7-44.1% of nitrogen during wheat growth came from nitrogen fertilizer. Before wheat jointing stage. NDFF values of wheat above ground in the treatment of surface layer fertilization were much higher than those in the treatments of subsurface and deep layer fertilization. Some improvement ways including ordinary cultivation with surface layer fertilization and cultivation by gathering soil with deep and subsurface layer fertilization could significantly increase the yield of wheat.