Assessment Of Soil Erosion Sensitivity In Karst Region Based On 3S Technology

Soil erosion sensitivity refers to the possibility of the occurance of soil erosion under natural conditions.The evaluation of soil erosion sensitivity is an important part of ecological environment assessment,and can provide scientific basis for ecological protection and construction by evaluating the sensitivity of ecosystem to human activities and identifying the areas which are easy to form soil erosion.Guizhou karst area has a fragile natural ecosystem,deep gullies,complex terrain and serious soil erosion.This paper chose Luodian County of Guizhou Province as the research area.Based on the analysis and establishment of the assessment indicator system and evaluation model of soil erosion sensitivity in the study area,the data of the vegetation coverage,terrain factor information and land-use type in this study area were obtained according to the 3S technology.And then the sensitivity of soil erosion in Luodian County was evaluated.Meanwhile,the landscape spatial pattern of soil erosion sensitivity in the research area was studied in this paper.Soil and water loss in the study area was also studied by combining with the soil erosion sensitivity from the perspective of the landscape.Then the landscape pattern of soil erosionsensitivity was analyzed from plane dimension and vertical dimension.Finally,the causes of soil erosion in the study area were discussed and the preventive measures were put forward.The main conclusions of the paper are as follows:(1)The sensitivity of rainfall erosive factor in the study area was concentrated in the moderately sensitive interval;The sensitivity of soil erodibility factor which was dominated by extremely sensitive area occupied the area of 54.62% in the research region.Sorted by size,the rest were followed by highly sensitive area,mild sensitive area and insensitive area;The sensitivity of topographic factors which was dominated by highly sensitive area and extremely sensitive area occupied the area of 54.5% and44.61% in the research region,and the distribution of the rest regional grades was very small;The sensitivity of vegetation cover factors which was dominated by mildly sensitive area occupied the area of 47.74% in study area.And the rest were(2)followed by insensitive area,highly sensitive area and moderate sensitive,accounting for 28.24%,19.34% and 4.68% respectively.(3)The sensitivity level of soil erosion in the study area was divided into three levels.There were mildly sensitive area,moderately sensitive and highly sensitive area,insensitive area and extremely sensitive area respectively.The whole was mainly in moderately sensitive area,which occupied the area of 73.44% in the research region.(4)From large to small,the area of soil erosion intensity at all levels in the study area was : moderate erosion,mild erosion,strong erosion,micro-erosion,strong invasion and severe erosion.Among them,moderate erosion rate accounted for75.46% of the total area of the study area,occupying absolute dominance.The distribution of soil erosion grade in the study area was basically consistent with the distribution of soil erosion sensitivity.(5)The sensitive area of soil erosion in the study area was dominated by moderately sensitive landscape.The degree of landscape fragmentation was low and the edge of the patch was complex.Among them,the soil erosion sensitive landscape of Luo Kun Town,Hongshui River Town,Maojing Town and Fengting Township was dominated by moderately and highly sensitive landscape,and the sensitivity of ecosystem to human activities was high.(6)In the low and middle elevation zone of the study area,the soil erosionsensitivity level was mainly moderate and high with high degree of landscape fragmentation and poor patch stability.The sensitivity of the ecosystemto human activities was high and in the area,human activities were frequent and soil erosion was not optimistic.In the high elevation zone,with the increase of the elevation value,the soil erosion sensitivity level was mainly mildly sensitive and moderately sensitive.Soil erosion was mainly affected by natural factors.Soil erosion sensitivity level,landscape fragmentation degree and plaque stability showed a decreasing trend,and the sensitivity of ecosystem to human activities was low.