| The erosion of the soil is widespread and the flow is high,leading to the deterioration of the ecological environment.This exacerbates the soil erosion and the increase of soil erosion,which has aggravated the soil erosion.This vicious cycle restricts the development of all aspects of our country.In this study,the USLE model was used to calculate the soil erosion factors,soil erodibility factor,vegetation cover factor,slope and slope length factor,soil and water conservation measures by using GIS and RS technology as quantitative and qualitative research methods.Factors,etc.,the final Ningxiang County soil erosion intensity grade distribution map.Then,the factors such as different elevation,slope,vegetation coverage and land use type and soil erosion were analyzed,and preventive measures were put forward.The conclusions are as follows:1.The present situation and spatial distribution of soil erosion in Ningxiang County in 2015 were analyzed.The average soil erosion modulus of Ningxiang County in 2015 is 2821.27 t/km~2a,which belongs to moderate erosion grade,the maximum soil erosion modulus is 90127t/km~2a,the minimum erosion modulus is 0,and the total annual erosion is 815000 tons.The soil erosion in Ningxiang County is mainly in the areas of micro-erosion,severe erosion,mild erosion and high soil erosion modulus in the northwest,southwest and central mountainous areas which landforms mainly mountainous,higher terrain,a high degree of gap,prone to soil erosion.2.The relationship between soil erosion and the influencing factors of USLE model in Ningxiang County was analyzed.(1)In different elevation zones,The higher the soil erosion intensity is,the higher the soil erosion intensity is,the elevation is positively related to the soil erosion intensity,and the elevation is negatively correlated with the erosion area.The range of micro-erosion area is the largest in the area of<200m,and the erosion is distributed in all elevations.Most of them are concentrated in mountainous areas and higher areas,and soil erosion prevention and control work needs to be strengthened.(2)In different slope zones,the soil erosion area in Ningxiang County is the highest in the slope zone of less than 5°,the slope below 25°,and the soil erosion area is reduced with the decrease of the slope.Soil erosion at moderate and below intensity levels occurs mainly on slope zones of less than 5°.The intensity and ultimate soil erosion mainly occur in the[8°,15°)slope zone.In the gentle slope area,it should be noted that the slope is less than 25°Areas,in mountainous steep areas,should focus on monitoring the slope[8°,15°)and[15°,25°)areas,to prevent the increase in soil erosion.(3)Soil erosion in Ningxiang County was mainly distributed in areas with vegetation coverage[45%,60%),[60%,75%)and greater than 75%in different vegetation coverage.With the increase of vegetation coverage,Soil erosion area gradually increased.In the micro-erosion,the proportion of vegetation coverage is greater than 5°,and the vegetation coverage is more than 75%.As the area of Ningxiang County is large,the man-made activities impact,leading to increased soil erosion area.(4)In different land use types,soil erosion is mainly from the area of large to small forest land>paddy field>urban and rural residential area and traffic>dry land>grassland>waters>bare land,and micro-erosion mainly.3.According to the present situation of soil erosion in Ningxiang County,the following measures are put forward,such as perfecting and implementing the law of soil and water conservation,establishing the law enforcement system of soil and water conservation supervision,increasing capital investment,introducing advanced technology,adopting small watershed as a comprehensive management and rational use Resources,good soil and water conservation monitoring and forecasting work. |
