土壤风蚀量随残茬高度的变化规律研究

在内蒙古自治区武川县建立农田土壤风蚀试验区,采用内蒙古农业大学研制的移动式风蚀风洞和旋风分离式集沙仪,直接在农田上观测不同残茬高度条件下的农田风蚀土壤损失情况。试验结果表明:土壤风蚀量和扬起沙尘的高度随风速的增加而增加,随着作物秸秆残茬高度的增加而降低,且输沙量与高度变化符合指数函数关系,土壤颗粒主要集中在近地表层内运动。保护性耕作可明显地提高启沙风速,减少农田土壤损失,当秸秆高度为30 cm时,风蚀量仅为传统耕地的1/4左右。

The Study on the Changing Laws of Wind-Blown Mass Affected by Stubble Height

Field experiments of soil wind erosion were established on the farmland in Wuchuan,Inner Mongolia to measure the soil loss by wind erosion under different stubble height treatments.A movable wind erosion tunnel and whirl type separation sand sampler designed by Inner Mongolia Agricultural University were used to collect the soil particles during the soil erosion by wind event.The results showed that with wind speed increasing,wind-blown mass and height of the particles suspended increased,while with stubble height increasing,mass and height of the particles suspended decreased.Also the relationship between the mass of the particles suspended in the air and the height fited an exponential function and the majority of the eroded materials moved near the surface.Compared with conventional moldboard plough practice,conservation tillage with 30 cm height stubble could remarkably increase threshold velocity and reduce the soil loss by about 3/4.