Study On Soil Erosion Change In Pengyang County Of Ningxia Based On GIS And RUSLE Model

Soil erosion has seriously affected the regional natural ecological environment.Therefore,it is necessary to effectively control the soil erosion and recover and protect the regional ecological environment in the Loess Plateau.Pengyang,the national key area of soil and water conservation,has the most serious problem of soil erosion in Ningxia.Since 2000,Pengyang county has been identified as a pilot county to return the grain plots to forestry.It has carried out a series of ecological restoration and construction projects,such as the green for grain project,small watershed management,soil erosion management.By carrying out these projects,the forest coverage rate has obviously increased,the soil erosion has been effectively controlled,which achieved a remarkable result.The comprehensive management of soil erosion in "Pengyang Model" has become a national ecological construction example.On the regional scale,through decades of governance,Pengyang,as the typical ecological restoration,needs to solve the impact on the variation characteristics of soil erosion under the influence of human production activity.Therefore,the study of Pengyang ecological engineering of soil erosion characteristics in different periods and different areas,can give benefit evaluation of the ecological construction on the county scale as well as provide the scientific basis for soil erosion prevention.Through the field survey data,the regional geographical basic data and the remote sensing data,the research,based on the ArcGIS,applies RUSLE to study the change of soil erosion of Pengyang from 2000 to 2014.By giving quantitative expression to the impact factor of soil erosion,analyzing the temporal and spatial variation of soil erosion and studying the human effect on the soil erosion,the conclusions are drawn as follow:(1)From 2000 to 2014,the overall situation of soil erosion has improved in Pengyang.In 2000,the soil erosion in Pengyang is mild.In 2008 and 2014,the erosion is slight,which is the same as the measured data of annual sediment runoff.In other words,the soil erosion conservation in Pengyang has restrained the soil erosion effectively.(2)From 2000-2014,the situation of soil erosion in Pengyang is different in different space distributions.In the north,the soil erosion modulus and erosion amount tend to increase in Anjiachuan watershed Water conversion also plays a part.However,under the influence of rainfall,the erosion increases.In the south,the situation of soil erosion in Red River changes a little,which is related to a few water conservation in this area.In the middle,the erosion in Ruhe River tends to be weakened,especially when the Ruhe River enters the upstream area of Pengyang,which is the greatest contribution to the soil and water conservation.(3)Human effects,especially the change of vegetation cover and the implementation of soil and water conservation have effectively inhibited the soil erosion in Pengyang.(4)Returning the grain plots to forestry(grass)has a positive effect on reducing soil erosion.From 2000 to 2014,with the large amount of farmland transfer,the erosion reduction of abandoned farmland is remarkably effective in 2014.The erosion modulus decreased by 27.44 t·hm-2·a-1,and the erosion rate reduced by nearly four times.(5)The change of vegetation cover was influenced by the change of rainfall,which affected the soil erosion.While the increase of water conservationhas significantly effect on the soil conservation.For the study area,the main factors of soil and water conservation are returning farmland to forest(grass),terraced fields,fish scale pit preparation,"88542"soil preparation,and etc.By comparing the water conservation at the end and its actual situation,it can be seen that the implementation of water conservation can restrain the soil erosion.From the change of the soil erosion intensity,the inhibiting effect of water conservation on the intensity erosion is more obvious.