Analyzing The Factors That Caused The Rocky Desertification Of Beimen River Basin In Wenshan Qiubei County,Yunnan

Genetic mechanism and governance of rocky desertification have made a more in-depth study previously, but basically it is about qualitative analysis, quantitative research is still inadequate. Based on this, article use Spot-5remote sensing data of2007to make Desertification quantitative research of Beimen River basin at Wenshan Qiubei County Yunnan Province by RS, GIS technology, and using BP neural network model to evaluate Beimen River basin desertification risk. In order to provide theoretical support for rocky desertification prevention and treatment at Beimen River basin, and target treatment according to local conditions.Research has made major achievements as follows:(1)The results show that:rocky desertification is subject to joint action of natural and human factors and formation in Beimen River basin. Carbonate rocks are widely developed, it provide the material basis for rocky desertification development. The rock that coexistence with Limestone and slate rocky is most concentrated area of rocky desertification development. limestone exposed area is easier for desertification occurred than Dolomite exposed area; Regional faults control the distribution of carbonate rocks and cause surrounding rock broken, varying degrees desertification development rate is declining as the increased distance from fault; The above of moderate desertification development rate increases with increasing altitude; slope affects the erosion intensity and soil erosion, which affects the area of rocky desertification occurrence, rocky desertification is closely related to human activities, Rocky desertification is mainly distributed in the range of human activities within0-1000m, Human activity to some extent contributed to the occurrence of rocky desertification.(2)The research Select the lithology, topography, land cover, and affected range of human activities as the Rocky desertification impact factors, and according to different development of rock desertification rate, we refine each factors ulteriorly. Finally we Selected12evaluation as an input layer to construct BP neural network model of rocky desertification risk assessment of Beimen River basin. According to the rocky desertification risk assessment, Beimen River basin is divided into four rocky desertification risk rating level as follow, without rocky desertification risk zone, Slight rocky danger zone, moderate risk rocky desertification zone and severe rocky desertification danger zone. Each level selected20samples, in total80samples as BP neural network model training and testing,15samples use for training, and the remaining20for testing.18samples meet the requirements, the correct rate is90%.(3) Using the BP neural network evaluation model to evaluate rocky desertification risk of the Beimen river basin.Results show that75.04%area of the basin affected by different degree rocky desertification, the impact of desertification weaken gradually from west to east. For characteristics of danger area of severe rocky desertification as follow, high altitude, steep slope, low vegetation coverage, large limestone, slate rock area, no surface river development, and affected by unreasonable human activities,such as slope tillage and deforestation, conversion of cropland to forest, strictly prohibiting slope tillage, building water storage projects, planting "drought enduring plant, Calcicole, rock plants" and so on are a good ways to restore regional ecological environment; The natural and cultural conditions of danger area of moderate rocky desertification is different between southern basin and northern basin, the characteristics of northern basin is low altitude, slope steep and less residents, this area should be given priority to prevent and control water erosion, the characteristics of south basin is high altitude, slope is slower, and the distribution of residential areas and cultivated land is relatively concentrated,this area should mainly standard unreasonable human activities; the danger area of Mild rocky desertification and the danger area of none rocky desertification should be put prevention first.