Reserach On Soil Erosion And Land Use Change And Its Relationship In Yinjiang River Basin Of Guizhou Province

At present,soil erosion as one of the main environmental effects caused by land use/cover change(LUCC)is the result of the interaction between human activities and the natural environment.The Yinjiang River Basin belongs to the important tributary of the Zhongjiang River in the Yangtze River system.It is located in the Tongren area of Guizhou Province,with a drainage area of 1251.6km~2.The karst landforms in the basin are widely distributed,the natural environment carrying capacity is poor,and the droughts and floods are frequent.The long-term impact of human activities,land use Unreasonable,soil and water loss seriously lead to rocky desertification is the biggest ecological problem in the region.Therefore,it is necessary to explore the law of spatial and temporal variation and mutual influence of land use and soil erosion in the basin.This study combines RS and GIS technology to extract the main soil erosion impact factors such as land use,slope and vegetation coverage by using TM remote sensing images from 1990 to 2015,and collect soil types and daily rainfall data around the basin and basin.The revised soil erosion analysis model(RUSLE)calculates the soil erosion intensity classification map.This paper analyzes the characteristics and driving factors of land use change in the basin during the study period,and introduces the landscape pattern method to explore the temporal and spatial variation characteristics and trends of soil erosion;and through the main factors of different land use types,and long sequence rainfall and Other factors affecting soil erosion changes such as rainfall in different seasons and different rock exposure areas.On this basis,the land use change and the temporal and spatial changes of soil erosion in the karst trough areas on both sides of the basin are discussed.The relationship between human activities and land use change and soil erosion in the entire Yinjiang River Basin is analyzed.The main findings are as follows:1.The dryland is decreasing year by year,the proportion of construction land is small but increasing year by year,and the rate of change is difficult.The forest land is increasing year by year,and its area has always been in the dominant position in the basin,while other land use types are fluctuating.The trend;cultivated land(dry land,paddy field)is distributed along both sides of the river valley;the construction land is distributed in the low-lying area of the river valley,along the direction of the valley,so the land use pattern in the basin is affected by the topography and the river.Big.2.Soil erosion in the basin was dominated by extreme intensity erosion in 1995.In 2000,it was dominated by moderate and mild erosion.In 2010,it was dominated by mild and slightly erosion.In 2015,it was dominated by micro-erosion,and erosion type was transferred.The violent and extremely strong grades in the middle are more moderately transferred to the moderate and light grades.Over time,the erosion of the whole area is effectively alleviated;in terms of space,the higher erosion grades are mainly distributed in strips.The direction of extension is consistent with the flow direction of the river and the terrain of the trough.Among them,the soil erosion risk level in the non-karst area is higher than that in the karst area,but the improvement of erosion status is also the most obvious.Relatively speaking,the improvement effect of the karst area is weak,so the soil and water conservation work in the karst area will remain the focus in the future.From the perspective of landscape pattern,the number of landscape patches with strong erosion and severe erosion is much reduced,and the landscape shape tends to be regular.The area-weighted patch fractal dimension becomes smaller,indicating that human influence on this type of landscape is strengthening.And eventually maintained at a certain level.The landscape type of the whole river basin tends to be simpler,and the soil erosion status is more and more dominated by the slightly erosion and mildly eroded landscape types,indicating that the erosion status of the whole watershed is effectively alleviated.3.The soil strength index of each land use type has a downward trend,but the soil erosion intensity index of the hard-to-use land is the highest;the land use change of forest land and dry land has obvious correlation with the soil erosion intensity index,and the area of forest land increases.The soil erosion intensity index decreased;while the dryland area increased,the soil erosion intensity index increased.The conversion between land use types has a profound impact on soil erosion.The conversion of grassland and forest land into dry land,paddy fields and construction land has an effect on soil erosion;on the contrary,when dry land,paddy fields and construction land are converted into grassland and woodland,When low-coverage grassland is converted into medium-high grassland and woodland,it can significantly improve soil erosion in the basin;difficult land can be easily converted to grassland or even forestland relative to other land types,which has a certain effect on soil erosion improvement.4.In addition to the winter less than the winter,the frequency of erosive rainfall in the other three quarters is relatively large.Therefore,there will be erosive rainfall in the basin throughout the year,combined with the cultivated land habits of the local spring-sown autumn species.Coverage,so the rainfall erosion in spring and autumn can not be ignored;the area where the rock exposure area and the land border can be used as an indicator of soil erosion in the field.The erosion status is:no vegetation cover rock exposure area>fruit forest land rock exposure area>The abandoned grassland is covered with rocky exposed areas.The rocky exposed area exacerbates soil erosion,which is intense and irreversible in rock-exposed areas without vegetation cover.5.The topography and rivers in the basin determine the local land use patterns and congenital soil erosion characteristics of the basin.However,human activities play a major role in controlling soil erosion in the study area.When people can actively and consciously improve the ecological environment,the soil erosion condition is significantly improved,and then the effect of human activities on improving soil erosion over time.It is weaker than before.