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美国伊利诺大学农学系玛洛试验地(Morrow Plots)建于1876年,是美国最早用来研究种植制度和施肥效应的试验地。我们通过养分、土壤结构、土壤水分等测定,结合历年的产量,研究玉米连作、玉米—大豆轮作和玉米—燕麦—三叶草轮作以及土壤施肥处理对土壤性状的影响。玉米连作使土壤有机质和全氮减少一半以上,其他营养元素也相应降低,土壤容重增加,孔隙度减少,结构变坏,土壤蓄水保墒能力减弱。而轮作结合施用有机肥料和化学肥料,有利于改善土壤理化性状和作物生长的环境条件,使作物高产稳产。
Morrow Plots, Department of Agronomy, University of Illinois, USA, was founded in 1876 as the earliest site in the United States to study cropping systems and fertilizer effects. Based on the measurements of nutrients, soil structure and soil moisture, we studied the effects of continuous cropping of corn, corn-soybean rotation and corn-oat-clover rotation on soil properties. Continuous cropping of corn reduced soil organic matter and total nitrogen by more than half, and other nutrients also decreased. Soil bulk density increased, porosity decreased, structure deteriorated, soil water retention capacity decreased. The rotation combined with the application of organic fertilizers and chemical fertilizers is conducive to improving the soil physical and chemical properties and crop growth environmental conditions, so that high and stable crop yield.