Prediction Of Soil Erosion Trends In Karst Areas Based On CA-Markov Model

The karst area in southwestern China has more people and less land,and the soil erosion is serious.The relatively harsh natural environment restricts the development of local social economy.In the process of building an ecologically civilized society,scientific prediction of the development trend of soil erosion is of utmost importance.This article takes the prediction of soil erosion trends in county areas of karst area as the research subject,and takes Qinglong County of Guizhou Province as the research object,using ARCGIS10.2,ENVI5.1 and IDRISI17.0 software platforms,using remote sensing surveys,statistical analysis of statistical data,transfer matrix and other methods.The changes of soil erosion in the study area were studied,and the reasons for the changes were analyzed.Finally,based on the CA-Markov model,the development trend of soil erosion in the region was scientifically simulated and forecasted,which provided the basis for decision-making for the local government to control soil erosion.The treatment of soil erosion in Longxian County and even in the karst area of southern China has important theoretical and practical significance.The main research results of this paper are as follows:(1)Three phases of soil erosion data.The soil erosion in the study area in 2006 had the highest erosion area of 712.93km2,followed by moderate erosion with an area of 249.02km2,the lowest was severe erosion with an area of 22.58km2,and the soil erosion area was 596.87km2,accounting for 45.57% of the county's land area;In 2011,the highest erosion area was 751.78km2,followed by mild erosion with an area of 253.87km2,the lowest was severe erosion with an area of 17.63km2,and the area of soil and water loss was 558.02km2,accounting for 42.6% of the country's land area;In 2016,the area with slight erosion was still 782.3km2,followed by mild erosion with an area of 239.13km2,the lowest was severe erosion with an area of 20.6km2,and the area of soil and water loss was 527.5km2,accounting for 40.27% of the county's land area.(2)Change law of soil erosion.The general change trend of soil erosion erosion intensity is the overall increase of slight erosion and light erosion,and the overall decrease of moderate erosion,strong erosion,extremely strong erosion and severe erosion.From the perspective of time,the proportion of soil erosion area from 2006 to 2016,the proportion of soil erosion area dropped from 45.57% to 42.6% and then dropped to 40.27%.It was concluded that the area of water and soil erosion in the study area showed an overall gradual decline trend;from a spatial point of view In 2006-2011,changes(decrease)were mainly concentrated in Qingzhong and Qingbei areas,and changes(decrease)were mainly concentrated in Qingzhong and Qingnan areas during 2011-2016.(3)Reasons for change.There are four main reasons.First,the comprehensive management of soil erosion using the small watershed as a basic unit has been vigorously carried out in Qinglong County,and 18 small watersheds have been treated.The treated area has reached 376.64 km2,accounting for 28.76% of the country's total land area;Second,forest land in the study area The increase in the area of water,land and construction land,and the decline of cultivated land and grassland area led to changes in land use and thus changes in water and soil erosion.Third,the experience of years of soil and water loss management has resulted in a unique model of Qinglong;Fourth,the standardized management of administrative departments,strict soil and water conservation law enforcement and advocacy and people's ideological awareness.(4)The prediction of soil erosion in the study area in 2021 was made.The predicted result is that the slightly eroded area decreased in 2021,resulting in a slight increase in the area of soil erosion in the study area.In the type of erosion intensity calculated as the soil erosion area,mild erosion is still dominant,moderate erosion and strong erosion continue to decrease,which are 13.63km2 and 2.71km2 respectively.At this time,the extremely strong erosion and severe erosion in the study area are basically Maintain a stable situation.