黑土农田极端侵蚀对土壤质量及作物产量的影响

Effects of Extreme Soil Erosion on Soil Quality and Crop Yield in Mollisols Farmland

在黑土层厚度为30cm、过渡层(母质层)厚度为40,70cm下的坡耕地上,采用人为剥离0,30,70cm土层以及沉积30,70cm土层,建立田间模拟试验小区,研究了黑土坡耕地极端侵蚀对土壤理化性质及玉米籽实产量的影响。结果表明:与无侵蚀处理相比,表土剥离30,70cm、沉积30,70cm处理均导致耕层(0—20cm)土壤容重、质量含水量和储水量显著增加,土壤孔隙度、>0.25mm水稳性团聚体含量、团聚体平均重量直径、几何平均直径、田间持水量、饱和含水量及养分含量均显著降低;表土剥离30,70cm处理下玉米产量分别减产42.1%和52.6%;沉积30cm处理下玉米产量与无侵蚀处理间没有显著性差异,而沉积70cm处理下显著减产12.4%。极端侵蚀无论是表土剥离还是沉积均导致土壤质量的下降,致使全坡面耕层土壤供肥保肥能力降低,最终造成玉米减产。

To investigate the effects of extreme soil erosion on physical and chemical properties of soil and crop yield,simulated experiments were conducted in topsoil（30 cm）,transition layer（40 cm）and parent material layer（〉70 cm）of Mollisols farmlands.Treatments including 70 cm topsoil removal,30 cm topsoil removal,no eroded soil,30 cm sediment deposition and 70 cm sediment deposition were set respectively.The results showed that compared with no eroded soil,soil bulk densities,soil mass water contents,soil water storages of the other four treatments were all significantly increased in tillage layer（0—20 cm）,while soil porosities,contents of soil water stable aggregates were greater than 0.25 mm,mean weight diameters,geometric mean diameters,field capacities,saturated moistures and soil nutrient contents of the four treatments were all significantly decreased.Furthermore,compared with no eroded soil,corn yields of the treatments of 30 cm and 70 cm soil removal reduced by 42.1% and 52.6%,respectively.There was no significant difference in corn yield between no eroded soil and 30 cm sediment deposition.Corn yield of the treatment of 70 sediment deposition significantly decreased by 12.4%.Thus,extreme soil erosion,no matter topsoil removal or sediment deposition,will lead to the decline of soil quality,reduce soil fertilizer supply and conservation ability,then reduce corn yield.