The Coupling Relationship Between LUCC And Soil Erosion In Karst Region

The karst region is known to all ecologically fragile areas in China.Soil erosion as the main feature of rocky desertification and land degradation restricts the development of the region,but also the ecological and environmental problems in the region's current problems to be solved.Karst region soil formation process is slow and complex,coupled with a large population,the obvious contradiction between people and land,human use of land and structure is such that the surface cover,runoff,soil texture and other changes affecting soil erosion,and soil erosion,declining soil fertility land degradation and land use structure and layout constraints,studies have shown that the irrationality of land use on soil erosion and structure of a reinforcing effect,and soil erosion aggravated rocky desertification will intensify the contradiction between people and the ecological environment more severe.Therefore,the study of Bijie Prefecture land use and soil erosion in the relationship is conducive to ecological protection of the rational allocation of limited land resources and the Karst region,regional land use planning and soil and water conservation and other macro policy-making departments to provide theoretical support.Taking Bijie Prefecture 1990,2000,2010,three of landsat TM and ETM + data as a source of information,based on standards issued by the Chinese water industry,the use of RS and GIS technologies to extract Bijie Prefecture class,slope and vegetation three indirect factor data,on this basis,to produce soil erosion map in Bijie Prefecture and estimated the amount of soil erosion in Bijie Prefecture,Bijie Prefecture to analyze the temporal changes in class and change characteristics of soil erosion,and to explore the coupling between the two relationship.The main conclusions of the study are as follows:1.The land use structure in Bijie Prefecture in the forest,farming,grass largest proportion,according to the size order of woodland> farmland> grassland in 1990 between 2010;dynamic utilization of Bijie Prefecture of 0.088%,are very slowly changing type,continued reduction of arable land,woodland,resident and industry land continues to increase,grassland,water and unused land there after the first and increased tendency to not use a single land use dynamics of land use show that the value of the growth rate of the most severe type,13.39%.Between different land type conversion occurs mainly in Bijie Prefecture between the three main categories to increase woodland vegetation coverage is improved,rain shutoff capability enhancements,in addition to woodland and grassland into arable land and the area mostly from arable land continued to decline indicating that excessive reclamation situation has improved,thanks to the Grain for Green ecological Engineering,grass area is improved.Cultivated land is mainly distributed in less than 25 ° slope belt,mostly in the slope of 8 ° the following areas;as slope increases,reduction of arable land distribution area,there is a critical point of 15 °-25 °.Various land use types in the elevation band profile with elevation has increased after the first reduction of the parabolic trend,peaking at an altitude of 2000 meters,the height of each land use type to bring the distribution area of Zhongshan Sort by size> low mountains> High Zhongshan> hilly.2.1990-2010 Bijie experimental area soil erosion intensity level to micro,mild to moderate erosion mainly of slight erosion is not included in the erosion area is eroded area proportion of the total area of Bijie test were 70.22%,71.79%,64.49%,1990,2000,2010,average annual erosion modulus of 221.51 t /(km2 · a),228.83 t /(km2 · a),190.75 t /(km2 · a),soil erosion intensity and the degree of a downward trend.1990--2000 years of erosion intensity increased total area of 2932.97 km2,erosion intensity decreased total area 2055.65 km2,overall erosion intensity increased.2000--2010 years of soil erosion intensity level up a total area of 6866.89 km2,dropped a total area of 10772.25 km2,soil erosion intensity weakening trend appears at this stage,soil erosion is improved.Soil erosion mainly in Bijie Prefecture slope of 5-35 ° slope areas,soil erosion intensity increases with the slope strengthened;increased soil erosion intensity with each elevation and elevation shows a parabolic trend,various types of soil erosion distribution area in the zone with altitude above sea level rise and increases in the range of up to 1500-2000 m altitude peak in the high altitude of more than 2000 m Zhongshan reduction.3.Bijie Prefecture land use and soil erosion coupling between stars from 1990-2010: Bijie Prefecture waters,residents of urban industrial land,unused land no significant erosion,the determination is of slight erosion,soil erosion intensity of different land types composite size: dry land> shrub land> middle coverage grassland> woodland> woodland> paddy field> high coverage grassland> low coverage grassland> other wooded land;arable land is the major land soil erosion occurs,arable land continued to decline,excessive reclamation situation has improved,soil erosion intensity index significantly smaller,the degree of erosion decreased,which indicates reduction of arable land and soil erosion is positively correlated;in woodland dynamic area,woodland continued to increase after the erosion of soil composite index increased first drop,show woodland increase soil erosion intensity negative correlation,but some forest remains were reclaimed and degradation,so that the extent of soil erosion aggravated;the grass dynamic region,after the grassland area decreased first and increased erosion intensity soil index first increases and then decreases indicating an increase of grassland and soil erosion negatively correlated increase is conducive to enhancing grassland soil resist force,but there are woodland to grassland degradation phenomenon will increase the degree of erosion,should strengthen the protection of grassland.Bijie Prefecture farmland,woodland and grassland mainly in between 1000-2000 m,with increasing elevation,arable soil erosion intensity index showed a decreasing trend after the first increases,there is a critical value of 1500m;soil erosion forest,grassland strength composite index increased with elevation and increased,peaking at 2000 m in elevation.