Study On Soil Erosion In The Yi River Basin Based On RUSLE Model

This paper took the Yi River Basin located in the hilly area of central Shandong province as the research object.Based on the remote sensing,meteorological data,soil data and DEM data as well as the methods of visual interpretation,interpolation,vegetation coverage index extraction,the RUSLE model was used to analyze the spatial-temporal pattern of soil erosion intensity in the Yi River Basin since 1975.And then,the relationship between soil erosion and land use / cover change was studied,the sensitivity of soil erosion was evaluated and the connection between sensitivity and soil erosion was discussed.Finally,using the the MARKOV model the soil erosion situation of the basin in 2025 was predicted,moreover,the accuracy of the prediction was tested.The main research conclusions as follows:(1)The soil erosion modulus of the Yi River Basin had experienced a trend of increased firstly and then decreased since 1975,among which the maximum value of soil erosion modulus appeared in 1995 and the minimum in 2015.There was an obvious spatial distribution characteristics of soil erosion intensity in the basin that the very strong and severe erosion were concentrated in the northern and southwestern mountainous areas of the basin,while the southeastern plains and the gentle slope of the river were mainly mitigated.(2)The change rule of annual average soil erosion intensity indexes was unutilized land> grassland> cultivated land> forest land.The region of the most vulnerable to erosion of unutilized land,forest land and grassland was 200-400 m above sea level,and 400-800 m for cultivated land.(3)The soil erosion modulus of cultivated land and unutilized land increased with slope degree increasing.The maximum soil erosion modulus of grassland often appeared at the slop between 15 and 25,and for the forest land that came more than 15.Given the soil erosion area and soil erosion modulus,it was necessary to strengthen soil and water conservation work of the 8°-25°area of the Yi River Basin.(4)The soil erosion modulus increased with the increasing of soil erosion sensitivity.The highly sensitive erosion area had the largest erosion amount,the moderate sensitive area had the largest erosion area,and the insensitive erosion ranked only second to the moderate sensitive area in erosion area but had the smallest erosion amount.(5)The prediction of soil erosion in the Yi River Basin in 2025 showed that the basin was dominated by micro-erosion in 2025,followed by mild and moderate erosion.And soil erosion above the moderate would reduce,while the micro-erosion and mild erosion would increase.