滴灌水肥一体化下施氮量对小麦氮素吸收及土壤硝态氮含量的影响

为探明华北地区山前平原水肥一体化条件下小麦合理的氮肥运筹。于2013-2015年2个小麦生长季,设置4个滴灌施氮量(N0-不施氮、N1-120 kg/hm~2、N2-240 kg/hm~2、N3-360 kg/hm~2)处理,研究滴灌水肥一体化下施氮量对小麦氮素吸收积累和土壤硝态氮含量的影响。结果表明:施氮量N1、N2和N3处理的小麦干质量及产量较处理N0显著增加,N1、N2和N3处理间无显著差异;施氮量对小麦茎秆的氮含量影响较大,但对籽粒氮含量的影响差异不显著;处理N3的小麦总吸氮量分别显著高于处理N0、N1和N2,但处理N1和N2之间无显著差异;氮肥收获指数以N2处理最高,氮肥当季回收利用率、氮肥农学效率、氮肥生产效率和氮肥利用效率均表现出随施氮量增加而降低的趋势;施氮量超过240 kg/hm~2,土壤硝态氮含量增加,且随种植年限的延长更加明显。采用一元二次方程拟合,获得小麦最高产量的施氮量为238.46~250.78 kg/hm~2,经济施氮量为174.28~207.18 kg/hm~2。综合考虑经济效益和生态效益,该条件下小麦滴灌经济施氮量以174~207 kg/hm~2为宜。

Effects of Nitrogen Amount on Nitrogen Absorption of Wheat and Soil NO-3-N Content under Drip Fertigation

The effects of nitrogen fertilizer application rate on the nitrogen utilization and soil NO-3-N content were studied to provide a scientific basis for reasonable nitrogen management under drip fertigation in Piedmont Plain of Hebei.The objective of this experiment was in this area.The experiment was conducted to determine the effects of nitrogen fertilizer application rate on nitrogen absorption and soil nitrogen content by using four nitrogen level of N0-No nitrogen, N1-120 kg/ha, N2-240 kg/ha and N3-360 kg/ha, under drip fertigation in field in 2013-2014 and 2014-2015 wheat seasons.The results showed that dry matter weight and yield of N1,N2 and N3 were significantly higher than N0,but no significant difference under N1,N2 and N3 treatments.The effect of nitrogen amount on N content of wheat stem was significantly and on N content of grain was no significantly.The total nitrogen uptake amount in wheat were significantly increased under the condition of N3 treatment compared with that of N0,N1 and N2,the total nitrogen uptake amount were no significantly difference between N1 and N2 treatments.The highest N harvest index appeared in N2 treatment.N recovery efficiency,N agronomy efficiency,N productive efficiency and N use efficiency were decreased with nitrogen amount increasing.Soil NO-3-N content were significantly increased as nitrogen fertilizer application rate was higher than 240 kg/ha,and that was more obvious with the increase of the planting time.The nitrogen application rate for highest yield was 238.46-250.78 kg/ha.The economic nitrogen application amount was 174.28-207.18 kg/ha,which was calculated according to the wheat yield and the nitrogen application amount by one variable quadratic equation.Considering the soil ecological environment and the economic efficiency,the optimal nitrogen application rate was at 174-207 kg/ha under the experiment condition.