【作者】 杨生茂； 郭天文；

【Author】 Yang Sheng-mao Guo Tian-wen(Institute of Soil and fertilizer, Gansu Academy of Agricultural Sciences, Lanzhou 730070) (State Key Laboratory of Arid Agroecology, Lanzhou University, Lanzhou 730000)

【机构】 甘肃省农业科学院土壤肥料研究所；

【摘要】 在甘肃省河西绿洲灌漠土上,通过6个施N水平的田间试验,研究了小麦/玉米带田施氮效应及施氮量对土壤剖面NO3--N含量的影响。试验结果表明,小麦/玉米带田施用氮肥时N素利用率随施氮量的增加而降低,其值为18.3%～44.8%。带田适宜施氮量为385.5 kg hm-2:在作物总吸收N量中,被小麦吸收的氮占33.9%,被玉米吸收的占66.1%。土壤剖面中NO3--N含量与测定时期有关:NO3--N含量随施氮量的增加而增加;施N量相同时,NO3--N从土壤表层(0～20 cm)到深层(160～180 cm)呈递减的趋势。在小麦/玉米生育期中,NO3--N含量在140～160 cm土层处有一个明显的峰值,其峰值随施氮量的增加而增大。因此,过量施N会造成NO3--N的积累和N的淋溶损失,并对地下水和土壤环境等产生潜在污染,据此,提出本区小麦,玉米带田推荐施N量不应超过450 kg hm-2。更多还原

【Abstract】 SummaryEffect of application of six levels of nitrogen on the amount of nitrogen absorbed by crops and content of NO3--N accumulated in soil was studied in a strip intercropping system of wheat-corn and an irrigation-desert calcareous soil by field trail in oasis irrigated region of Hexi, Gansu Province. Results showed that increased rates of application of N fertilizer affected the accumulation of NO3--N in soil, efficiency of N utilization and amount of N absorbed by crops significantly. The efficiency of N utilization decreased from 44.8% to 18.3% with the increase of amount of N applied. In the total N absorbed by crops 33.9% was absorbed by wheat and 66.1% by corn. The accumulation of NO3--N in soil depended upon the rates and time of N application. It increased in the soil with the increase of applied rate of N and decreased with the increase of depth of soil. The accumulation of NO3--N occurred remarkably at 140~160 cm depth of soil. It is certainly that excessive application of N fertilizer could cause the accumulation of NO3--N in soil profile and lose to the ground water by leaching. This would be a potential danger of poolution for the environment. Thus no more than 450 kg N per hectare to be applied in this region is recommended.更多还原