Spatial-temporal Variation Of Soil Erosion In The Losses Plateau And Its Response To Climate Change

As the most vulnerable ecological environment area, the Loess Plateau suffersthe gravestsoil erosion damage both in China and in the world. Soil erosion has been the primary obstacle that restricts the sustainable development of local economicandlocal society. The past few decades have seen significantclimate change, takingwarming-drying trend as its character in the Losses Plateau. The temperature, precipitation, vegetation cover, land use and other factors related to soil erosion are going through a set of variation. Soil erosion environment in the Loess Plateau have changed and continues to change dramatically. But the research on the effects of climate change on soil erosion in the area is still relatively lack.Therefore, it’s urgent to analyze the climate change regularity and its impact on soil erosion in the Loess Plateau area. Based on above, this paper studied thevariation ofsoil erosion environment as well as water erosion and climatic factor index of wind erosion.Moreover, the published research of wind-water erosion and freeze-thaw erosionin the Loess Plateauwere summarized.The conclusion is as follows:(1)In the last three decades, the warm desiccation’s tendency, with wind speed downward trends was quite obvious in the Loess Plateau.Water erosion region as well as wind-water erosion crisscross regionand wind erosion region has been through the same climate trends.The vegetation cover has shown an increasing trend in the Loess Plateau along with the three regions. The grassland and farmlandare two main kinds of the land use types of the Losses Plateau-Moreover, settlement has the most substantial changes in the various kinds of land use types, increasing significantly.Arable land, varying amplitude in second, has a certain decline. The variation of soil erosion environment, including meteorological factors and underlying surface factors, contributes to reduce the soil erosion in the Loess Plateau as same as water erosion region, wind-water erosion crisscross region & wind erosion.(2)The average water erosion modulus of water erosion regionin the Loess Plateau years is 5206 t/(km2·a), belong to intensive erosion.The average soil erosion modulus wasobvious downtrend in the water erosion region in the last thirty years, decreasing precipitation has played an important role in the trend. The rise of temperature in the water erosion region had certain promotion effect on the increase of vegetation cover, which, in turn, reducedthe intensity of water erosion. As for wind-water erosion crisscross region, the average water erosion modulus is 3769 t/(km2·a), belong to moderate erosion. The average water erosion moduluspresented earlier increase and later decrease trend, showing downtrend wholly in the last 30 years. Precipitation is one of the important factors affecting water erosion moduluschanging in the wind-water erosion crisscross region, with temperature showing no significant impact.(3)The average climatic factor index of wind erosion(C value) inwind erosion region in the Loess Plateau is 50.45, in the strong wind erosion risk level.Significant downward trend of C value has appeared during the last 30years, annual average drop is 0.7819. The average climatic factor index of wind erosion in the wind-water erosion crisscross region is 31.12,in the relativelystrong wind erosion risk level.With a downward but not obvious trend,the annual average dropof climatic factor index in the wind erosionis 0.0281.The change of wind speed is the main cause of the variationof climatic factor index of wind erosion. Furthermore, the change of wind speedis the most important cause of the C value dropped in wind erosion. By the combined effect of decreasing wind speed and reducing precipitation, the average climatic factor index of wind erosion in the wind-water erosion crisscross regionshowed a decline but not significant trend.(4)A significant positive interaction is found between wind erosion and water erosion, which makes the amount of complex erosion of wind and water is greater than bothrespectively. The wind-water erosion crisscross region is the most serious soil erosion area inthe Loess Plateau. The reduction of sediment dischargeofhyper-concentration riversin crisscross area representsthe decline trend of complex erosion of wind and water in the crisscross region, andclimate change prompted the process. There is freeze-thaw erosion in Loess plateau and freeze-thaw action can change soil properties, affectingthe soil erosion process. The research work on the spatial-temporal changeas well as the impact of climate change on freeze-thaw erosion in Loess Plateau needs to be carried out.