摘要
采用长期定位试验,研究了冬小麦—夏玉米一年两熟轮作下的施氮量与NO_3^-—N在土壤中的淋移关系,提出了该区单季作物的适宜施氮量。结果表明,增加施N量可明显增加土壤NO_3^-—N含量;随着施N量增加和施用年限延长,土壤NO_3^-—N积累层显著向土壤剖面深层移动;当施N量持续达到或者超过300kg/hm^2时,对地下水的威胁增大;本研究地区的单季施N量宜控制在225kg/hm^2以下。
A long-term experiment was carried out to investigate the effects of nitrogen fertilizer on the NO3-- N content and distribution in the soil. Six nitrogen application rates of 0, 75, 150, 225, 300 and 375 kg/hm2 were used. The results showed that crop yields increased with N application rate but nitrogen utilization efficiency decreased at the same time. In addition, soil NO3--N content increased with N rates. There were significant downward movements of NO3-- N in the soil profile, especially when the N rate was over 225 kg/hm2. When the N rate was above 300 kg/ hm2, the risk for groundwater pollution was substantially increased. This suggests the N rate for a single crop should not exceed 225 kg/hm2 in this region.
出处
《河北农业科学》
2003年第4期7-12,共6页
Journal of Hebei Agricultural Sciences
基金
河北省科技攻关项目(01220307D)
河北省自然科学基金(302444)
