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西北水保所李玉山通过30余年的实践与研究认为,渭北旱原当前在一定技术管理下产量是养分投入的函数。1949—1970年渭北传统农业以生态有机途径维持了养分低水平平衡、保持了75kg/亩的历史水平,70年代以后化肥的投入成为产量跃上新台阶的有力因素。旱地作物年度产量的波动性根源是年度降水供需的不平衡。在年降水584mm 的长武地区,由于水分不
Through more than 30 years of practice and research, Li Yushan of Northwest China Water Inspectorate believes that the current output of Weibei Upland is a function of nutrient input under certain technical management. In 1949-1970, traditional agriculture in Weibei maintained a low level of nutrient balance through ecological and organic means, maintaining a historical level of 75kg / mu. Since the 1970s, the input of chemical fertilizers has become a powerful factor in the output to a new level. The root cause of the annual fluctuation of dryland crops is the imbalance between supply and demand of annual precipitation. In the area of Changwu where the annual precipitation is 584mm, the water does not