基于高丰度15N华北平原冬小麦肥料氮的去向研究

【目的】在氮磷钾合理供应前提下，研究华北平原冬小麦肥料氮的去向。【方法】采用微区试验的方法，供给小麦高丰度的15N，在小麦收获时，测定15N的去向。【结果】冬小麦吸收的氮素来自肥料的比例为26.6%— 33.6%，对土壤氮的依赖程度在66%以上。肥料氮施入土壤后，小麦当季利用率为22.1%—32.4%，当季肥料氮的土壤残留率约占施氮量的29.6%—56.3%，其中60.3%—76.5%集中在0—40 cm土层，在土壤剖面中的残留率随土层深度增加而迅速降低。【结论】小麦生育期吸收的氮素66%以上来自土壤，氮肥当季平均利用率为28.2%，约40%的肥料残留在土壤中，成为土壤氮库的补充。

Fate of Fertilizer Nitrogen Applied to Winter Wheat in North China Plain Based on High Abundance of 15N

【Objective】 The purpose of this paper was to estimate the fate of fertilizer N applied to winter wheat under optimum nitrogen(N),phosphorus(P) and potassium(K) rates in north China plain.【Method】 A field micro-plot experiment was adopted and high abundance of15N was applied to wheat in this study.After harvest of wheat,the fate of15N was measured.【Result】 The result showed that about 26.6%-33.6% of the N taken up by winter wheat was derived from the applied fertilizer N,and 66.4%-73.4% of that was derived from the soil.The plant recoveries of N were in the range of 22.11%-32.36%,and soil residual N from applied N fertilizer were ranged in 29.6%-56.3%,of which 60.3%-76.5% centralized in 0-40 cm soil layer,and the amount of fertilizer N residue in soil profile decreased rapidly with the increase of soil depth.【Conclusion】More than 66% of nitrogen absorbed by winter wheat was derived from soil,the nitrogen utilization rate was 28.2% in the first season on average,about 40% of applied fertilizer N were remained in the soil,which might be a necessary supplement for the soil N pool.