基于CSLE的安溪县土壤侵蚀估算与分析

Estimation and analysis of soil erosion in Anxi county based on CSLE

安溪县是目前福建省水土流失最严重的区域,定量估算安溪县土壤侵蚀模数并分析其土壤侵蚀状况对当地水土保持和生态环境建设具有重要意义。以安溪县为研究区域,基于CSLE土壤侵蚀模型,开展2015年安溪县土壤侵蚀定量估算与分析。结果表明:1)2015年安溪县土壤侵蚀总面积为638.09 km^ 2,水土流失率为21.31%,其中以轻度流失为主,占总流失面积的74.04%。2)土壤侵蚀主要分布于安溪县中北部和南部区域,且以双溪流域和大畬溪流域土壤侵蚀最为严重,流失率分别为29.00%和32.19%。3)>15°~25°坡度带和海拔200~500 m区域内土壤侵蚀最为严重,>15°~25°坡度带内流失面积约占全县总流失面积的1/2,200~500 m高程带内水土流失率高于20%,茶园的无序开垦是造成该现象的主要原因。这表明2015年安溪县土壤侵蚀整体情况较为严重,应确定土壤侵蚀重点治理区域,有针对性地制订土壤侵蚀防护措施,改善土壤侵蚀情况。

[Background]Soil erosion leads to a decline in land productivity and a sharp deterioration of the ecological environment.It is one of the most prominent problems in China s ecological environment,and it is also a global disaster.Anxi county,located in the red soil area of southern China,the collapse in low vegetation and the disorderly reclamation and the lack of management of tea gardens make Anxi county the most serious soilerosion county in Fujian province.The use of remote sensing technology to estimate soil erosion is effective method that may quickly provide a scientific theoretical basis for local soil and water conservation and ecological environment construction,and has important practical significance.[Methods]In recent years,the soil erosion model has been widely used in soil erosion monitoring.Based on the CSLE soil erosion model,this paper quantitatively estimated the soil erosion modulus of Anxi county in 2015,and used soil erosion rate and soil erosion index to analyze the spatial distribution characteristics of soil erosion in Anxi county and its relationship with slope and altitude.[Results]1)The soil erosion in Anxi county was still serious.In 2015,the average soil erosion modulus of Anxi county was 379.72 t/(hm^2·a),and the average soil erosion modulus of soil erosion area was 1 029.02 t/(hm^2·a).2)In 2015,the total area of soil erosion in Anxi county reached 638.09 km 2,and the loss rate was as high as 21.31%,light loss with an area of 472.66 km 2,accounting for 74.04%of the total loss area,and the area of strong loss and above accounted for a small proportion,and about 2.94%of the total lost area.3)Soil erosion was mainly distributed in the north-central and southern regions of Anxi county,and the soil erosion was the most serious in the Shuangxi River Basin and the Dashe River Basin,the soil loss rate were 29.00%and 32.19%,respectively.The soil erosion index of these two basins was>4,also indicating the severity of soil erosion in these two basins.4)The soil erosion in the>15-25°slope zone and the altitude of 200-500 m was the most serious.The>15-25°slope in-band loss area accounted for about half of the total loss area of the county.The soil erosion rate in the 200-500 m elevation was higher than that 20%.Because the slope of>15-25°was of excessive reclamation and steep slope planting,and 200-500 m was an activity-intensive elevation belt,which also exacerbated soil erosion.[Conclusions]Due to the excessive reclamation of tea gardens and the failure of conducting land management according to the standard and collapsing hill,the overall situation of soil erosion in Anxi county is more serious.Relevant organizations should determine the key control areas for soil erosion,formulate soil erosion protection measures and improve soil erosion according to different causes of soil erosion,and therefore ensure the safety of the ecological environment.