Study on Response Relation between Eco-Environment Change and Soil Erosion Process in Reclaimed Forestland of Loess Hilly Region in China

摘要

The soil erosion of Loess Plateau is the main cause of the worse eco-environment, and the control of erosion environment is the key to ensure the eco-environment construction successfully. Based on the 10 year's data observed in the Loess hilly region, the paper studied the response relation between eco-environment change and soil erosion process after forestlands reclaimed. The results showed that when the man-made changed the eco-environment to reclaim forestland, the intensity of man-made soil erosion was more 1,000 times than that of the natural erosion. Taken the soil erosion modulus unit erosivity of rainfall as the index, the soil erosion intensity increased apparently with the erosive time eroded. Then from the analysis of soil physical and forces properties, in 10th year eroded after forestland reclaimed, the clay content and physical clay content decreased 2.74% and 3.01% respectively, which showed the soil particles had the tendency to skeleton soil, and the > 0.25mm water stable aggregate content also decreased 58.7%, the soil unit weight increased and the soil shear strength decreased, all of which were easier to occur soil erosion. The correlation analysis showed that > 0.25mm water stable aggregate content was the maximum effect factor to soil erosion, the partial correlated coefficient was 0.9728, and then were soil coarse grain and soil shear strength, the partial correlated coefficients were 0.8879 and 0.6020 respectively. The relation between the > 0.25mm water stable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed, which showed that the first and seventh year were the turn years of the soil erosion intensity after the forestlands reclaimed, revealed the change of eco-environment was the main cause to accelerate soil erosion. The degenerative soil eroded and eco-environment formed the peculiar erosion environment, which increased the soil erosion rapidly. So to return slope farmland into forest and grassland, to recover and reconstruct vegetation and improve the eco-environment were the key measurement to control soil erosion of Loess Plateau.