The Effects Of Water And Soil Conservation Of Different Land Utilization Types And Its Restoration Strategy In Napahai Basin

Napahai Basin plays huge roles in adjusting the surface runoff and river water and conserving water and maintaining the biological diversity. The research on the effects of water and soil conservation and its restoration strategy of different land utilization types in Napahai Basin has a positive significance due to its important status of ecological environment. In this thesis, firstly, by analyzing the influence of soil physic and chemical properties on soil erosion to put forward an appropriate path to reduce the soil erosion. Secondly, the correlation between rainfall and soil erosion and the effect of water and soil conservation about different land utilization types had been summarized by analyzing the influence of rainfall on soil erosion, this could be referenced for restoring ecosystems of Napahai Basin. Lastly, the environment impacts of water and soil erosion in Napahai Basin had been analyzed to provide some insights restoring ecosystems of Napahai Basin.Eight typical kinds of lands types were selected to study including.The grass land, pine forest, bare land, sweet wormwood herb recovery region, philadelphus delavayi recovery region, highland barley land, miscanthus stem land, rapeseed land. The correlation between physical and chemical properties and soil erosion had been examined. The results showed that a high soil erosion sensitivity of the soil in Napahai Basin had been proved. Different land use type had a different soil physical and chemical properties. The bulk density, fractal dimension, and content of organic matter had been verified significant correlationstosoil erosion. There were lower bulk density, lower fractal dimension, higher content of organic matter with grass land and pine forest. There were a higher bulk density, a higher fractal dimension, a lower content of organic matter with bare land. In turn, the grass land and pine forest were proved to have better abilities of soil and water conservation and the soil loss of bare land was proved to be the highest. The study found that the soil physical and chemical properties had been improved and the water and soil loss had been decreased when the bare land got vegetation restoration for three or five years. We could draw a conclusion that to reduce the bulk density and to increase the content of organic matter of soil could be good ways to reduce the soil loss.Additionally, the precipitation and the corresponding runoff and sediment yield were recorded. The results showed that grass land, pine forest, and slope land occurred better effects of water and soil conservation within all of these land use types under the same rainfall condition. An obvious soil and water conservation benefit of vegetation was further confirmed. Obviously, the bare land, with a relatively poor effect of water and soil conservation. But with the increasing years of vegetation, the soil texture and structure of bare land gradually improved, then the effect of water and soil conservation was gradually appeared. Therefore, appropriate vegetation restoration measures could be done to increase the surface vegetation coverage, to weaken the scouringaction by rainfall, to enhance the water retention capacity of vegetation, to decrease the soil erosion yield in Napahai Basin.The N and P in the soil of different use types in Napahai basin losing from surface runoff and losing from silt clay migration were studied. Its result of the environmental effects of soil erosion showed that the nutrient loss of bare land was far more than grass land, pine forest, slope cropland, repaired region. The nutrient loss of slope cropland was the highest in these land use types which were covered by vegetation. A conclusion was that soil nutrient could be strongly influenced by vegetation and tillage method. The loss of TN and TP was mainly migrated with sediment.From the above, the soil erosion could be effectively decreased by improving physical and chemical properties of soil appropriately. And the water retention capacity of vegetation could be enhanced by recovering the vegetation strongly. Additionally the reduction of non-pointsourcepollution could be realized by remediating the soil and water loss. Importantly, it is also critical to improve environmental awareness of local tibetan residence with forest planting and plants protection, which benefit the ecological restoration of Napahai basin.