不同肥力土壤小麦、大豆轮作施氮效应研究

为了解不同肥力土壤小麦、大豆轮作周年最佳施氮量和分配,对高、中肥力土壤小麦大豆轮作进行了不同施氮量效应研究,结果表明,施氮与不施氮相比,高、中肥力地块小麦平均分别增产为15.7%、41.9%,大豆平均分别增产为33.4%、46.8%;小麦、大豆氮肥偏生产力随着施氮量增加而降低,氮肥农学效率以处理3(麦N 210kg/hm2-豆N 90kg/hm2)最高,小麦、大豆氮肥贡献率均随着施氮量的增加先增后降;同等施氮量在中等肥力地块的产量效应高于高肥力地块的效应;从不同肥力小麦、大豆氮肥效应函数得出,高肥力条件下,小麦、大豆达到最佳产量时的施氮量分别为213.0kg/hm2和121.5kg/hm2;中等肥力条件下,小麦、大豆达到最佳产量时的施氮量分别为330.0kg/hm2和130.5kg/hm2,即河南省平原农区小麦、大豆轮作高、中肥力土壤周年最佳施氮量分别为334.5kg/hm2与460.5kg/hm2、小麦、大豆氮分配比例分别为1∶0.57和1∶0.40。

Effect of N Application in Different Fertility Soils in Wheat-Soy Rotation System

In order to know the annual optimal amount of nitrogen application and nitrogen distribution of different fertility soils in wheat-soy rotation system,the different nitrogen utilization efficiencies of high and middle fertility soils were studied.The result showed that the average increase rates of wheat were 15.7% and 41.9%,and the rates of soy were 33.4% and 46.8% under the nitrogen application treatments in high and middle fertility soils.The partial factor productivity of applied N of both wheat and soy decreased with nitrogen application increasing.The N agronomic efficiency was the highest with 210 kg/ha for wheat and 90 kg/ha for soy.With the nitrogen application increasing,the N contribution rate of both wheat and soy increased at first and decreased afterwards.Under the same amount of nitrogen application,the yield efficiency of the middle fertility soil was higher than that of the high fertility soil.Conclusions could be drawn from the wheat and soy N fertilizer response functions in different fertility soils.Under high fertility conditions,the N application amounts for the optimum yields of wheat and soy were 213.0 kg/ha and 121.5 kg/ha,respectively,while under medium fertility conditions,the N application amounts for the optimum yields of wheat and soy were 330.0 kg/ha and 130.5 kg/ha,respectively.