Soil Erosion Change And Prediction In Bazhong City Based On The Combination Of RS/GIS And RUSLE Model

The problem of soil erosion threatens the land that people depend on for survival and severely restricts the development of regional social economy.The causes of soil erosion in China are complex and vary significantly in spatial distribution,and an in-depth study of erosion law can provide reference for regional erosion management.Soil erosion research has now developed into a combination of spatial information technology and erosion models,which can accurately and objectively reflect regional erosion conditions and effectively monitor the spatial variation and dynamic evolution of erosion trends in real time,compared to traditional empirical statistics and physical models.As a typical example of soil erosion hazards in the mountainous areas around the basin of Sichuan Province,it is necessary to monitor the soil erosion situation in the city and predict its development,which is of great importance for the management of soil erosion and soil conservation work in the city.This thesis takes Bazhong city as the study area,and with the technical support of GIS,quantitatively characterizes the soil erosion impact factors in the city,and calculates the soil erosion in the study area in 2006,2010,2014 and 2018 by combining the RUSLE model.A qualitative and quantitative analysis of the spatial distribution characteristics and dynamic evolution trends of soil erosion in Bazhong City from 2006to 2018 will be conducted based on the results data of the four phases,and the driving factors influencing soil erosion will be explored using the geographical detectors.In addition,a CA-Markov model will be constructed to predict the soil erosion status in Bazhong City in 2022.The main contents and results of this study are as follows.（1）The algorithm for the soil erosion factor in Bazhong City was determined by taking into account the actual situation in the study area.The rainfall erosion force factor is obtained based on the monthly precipitation data from meteorological stations using the general simple algorithm;the soil erodibility factor is extracted using the soil productivity model（EPIC）;the slope factor is extracted using the segmental calculation method,taking into account the influence of different topography;the slope length factor is obtained using the general simple algorithm;the vegetation cover and management measures factor is extracted by the vegetation cover and factor calculation model;the soil conservation measures factor is extracted by taking into account the slope and land use data,and the factor is assigned to each category under different slope conditions.The vegetation cover and management factor is extracted from the vegetation cover and factor calculation model;the soil and water conservation factor takes into account the slope and land use data and assigns a factor to each category under different slope conditions.（2）Calculate the amount of soil erosion in Bazhong City in four phases and analyse the dynamic evolution of soil erosion.Based on the above results,the RUSLE model was used to extract information on the erosion status of Bazhong City,and then the city’s soil erosion transformation mode was specifically analysed.The results show that the soil erosion status of Bazhong City has generally developed in a positive trend during 2006-2018,and both the erosion area and the degree of erosion have been mitigated and improved accordingly.The area of light erosion and above in Bazhong City has shrunk from 6554.81km²to 4295.12km²over these 12 years,and the average soil erosion modulus has decreased from 2815.87t·km^-2·a^-1 to 1157.29t·km^-2·a^-1.The most dramatic change in erosion area between 2014 and 2018 was in the area of light erosion and above,with the area of light erosion and above decreasing by 20.43%from2014 to 2018,which indicates that Bazhong City has achieved corresponding results in soil erosion management over the years.（3）Exploring the spatial distribution characteristics of soil erosion in Bazhong City.Overlaying the four phases of soil erosion class data with slope data and land use,the results show that:medium and gently sloping slopes and medium slopes are mainly dominated by slight erosion with less erosion hazards,while steep slopes,sharp slopes and sharply steep slope areas are widely distributed with moderate and above erosion in addition to slight erosion.The soil erosion modulus of each land type under the same slope conditions:grassland>forest land>arable land>construction land,in general,slight and mild erosion is dominant in each category,and the erosion status of each category developed toward a low-grade posture during 2006-2018.（4）Exploring the factors influencing soil erosion based on the geographic probe.In the factor detector,the explanatory power of each factor is ranked as follows:slope factor>land type factor>landform type factor>rainfall factor>elevation factor>vegetation cover and management measures factor,among which slope has the strongest explanatory power of 39.59%on soil erosion intensity,which can be regarded as the dominant factor affecting soil erosion in Bazhong City.The interaction between the slope factor and other factors is obvious,which indicates that the slope factor also has a significant influence on the spatial distribution of soil erosion.（5）By verifying the reasonableness and reliability of the CA-Markov model,the CA-Markov model was used to predict the erosion situation in Bazhong City in 2022in combination with the data from the calculation results,and corresponding reference opinions were proposed for the future development of soil and water conservation work based on the prediction results.