The Soil Properties And Characteristics Of Runoff-sediment Yields Under Different Vegetation Cover Based On The Runoff Plot Experiment

Vegetation types and cover significantly effect on soil physical and chemical properties, soil water content and surface runoff and sediment yields. This paper chose 9 standard runoff plots with different vegetation covers in Changwu national field observation station of farmland ecosystem as its study area, monthly tested the rainfall, observed vegetation properties, soil physical and chemical properties and soil water content, recorded surface runoff and sediment yields after each erodible rainfall events from May,2013 to October 2014. Analyzed the role of runoff generation and sediment yields and the indicator factors under different vegetation cover. The results showed that:(1)The soil saturated conductivity, saturated water capacity, capillary water capacity, soil organic properties of runoff plots with grassland and sea buckthorn were obviously higher than other plots, but soil bulk density is smaller than others in soil layer of 0-40 cm under different vegetation covers. Grassland and sea buckthorn can enhance the physical and chemical properties of soil efficiently.(2)Soil water content had approximately similar temporal distribution of soil water content under different vegetation covers. Generally, soil water content in spring and winter higher than that in summer and autumn. In soil profile of 0-200 cm, soil water content had significant difference on its dynamics. However, soil water content increased following the increase of soil profile depth. Despite of different vegetation covers, soil water content increased steadily following the increase of soil depth under 200 cm. In the plot of grassland, annual mean soil water content reached about 20%, and soil water content of other plots were between 12%-15%. Grassland kept the higher soil water content than others in shrub and woodlands constantly.(3)The mean surface runoff and sediment yields of grassland were both the lowest among 9 different vegetation covers, and the woodland of arborvitae had the highest volume of runoff and sediment yields. The coefficient of mean runoff volume and sediment yield modules decreased by following the increase of canopy and vegetation covers. Meanwhile, runoff and sediment yields increased by following the increase of rainfall.(4)Generally, rainfall, vegetation canopy, and undergrowth cover, physical and chemical properties of soil, soil water content influenced on runoff generation and sediment yields, and the rainfall and vegetation properties played important role among these factors.