Study On Desertification Characteristics And Driving Mechanism Of Liaohe River Basin

The surface desertification is called "Earth cancer",which is one of the important reasons for the degradation of ecological environment and the decline of productivity.It is also an important ecological problem faced by the Liaohe River Basin.The Liaohe River Basin is an important grain production base in China.With the global warming and the large population growth,the human factors are becoming more and more prominent.The area of desertification in the Liaohe River Basin is expanding and becoming the new sand in Liaoning Province.Source,affecting regional economic development and ecological security.In-depth study of the characteristics of desertification in the Liaohe River Basin and its driving mechanism can help to understand the degree of desertification and its influence,and provide scientific basis for controlling the further expansion of desertified land in Liaohe River Basin and the treatment of desertified land.In this study,the sandy land of the Liaohe River Basin was used as the object of study,and the spatial and temporal characteristics of the desertification in the Liaohe River Basin were analyzed by means of ecological and economic data collection,field sampling survey and indoor remote sensing interpretation.The natural factors of desertification and human factors,to explore the driving mechanism of desertification land within the basin.Get the following conclusions:(1)The total area of desertification decreased from 2527.32 km2 in 1994 to 2013,and the population showed a good reversal trend.The existing sandy area of 3864.30km2,of which the total area of wind erosion and desertification is about 2666.50 km2,mainly distributed in Kangping,Zhangwu,Fuxin,Montenegro and other places.The total area of water erosion is about 1197.80km2,mainly distributed in Fuxin area southwest of Liaohe River Basin,sporadic in Changtu and Faku.(2)The annual average temperature of the Liaohe River Basin in 1994 to 2013 increased first and then decreased,and the annual average temperature increased from 8.34 ? in 1994 to 9.02 ? in 2007,then decreased to 7.91 ? in 2013,and the average temperature was 8.13 ?;the average annual precipitation is 622.15mm,the average annual precipitation from 1994 to 868.77mm down to the lowest in 2000453.74mm,and then increased to 2013 777.80mm,was significantly lower after the first increase trend.The average annual wind speed is 2.85 m/s in the Liaohe River Basin,and the annual mean wind speed trend is consistent with the annual average temperature trend.From 1994 to 2002,the wind speed gradually increased,and the precipitation decreased,which was easier to spread.(3)From the point of view of vegetation coverage,the coverage of vegetation in most of the Liaohe River Basin was higher in 1994 to 2013,and the vegetation coverage(NDVI)showed a trend of low to east.The eastern part of the eastern part of the Tiaoxing River Basin,the eastern part of Xintao County,Xifeng County,the eastern part of Tieling County and Shenyang City along the Liaohe River Xinmin County,Liaozhong County,Fushun City Qingyuan County,Panjin City Panshan County,Dawa County NDVI value is higher,Vegetation coverage is better;Kangping County,Zhangwu County,Fuxin County and Liuhe coastal areas of vegetation coverage is relatively low,can better determine the location of desertification.(4)The gray correlation method was used to select the natural factors and human factors affecting the sandy land of the Liaohe River Basin.The average annual precipitation,vegetation coverage,population density and cultivated land area showed a high correlation.Gray correlation analysis shows that the population number,cultivated land area and vegetation coverage are the main factors affecting land desertification.From the relative contribution rate,the proportion of the main natural factors and human factors to the total area of desertified land is 48.38%and 51.62%respectively.The desertification process is influenced by the combined effect of natural factors and natural factors on the desertification process.It is pointed out that the desertification process of the watershed land in the driving factors of land desertification should be the common factor of human factors and natural factors the result of.(5)The results of gray prediction model show that the total area of desertified land in Liaohe River Basin is decreasing gradually in the next 20 years.It is estimated that the area of desertification is 3445.74km2 in 2033,accounting for 10.90%of the total area of Liaohe River.The area of mild desertification is 3109.25 km2,the moderate desertification area is 300.80 km2,and the area with severe and extremely severe desertification is 35.69 km2.With the help of a series of policies and favorable measures in the construction of ecological civilization,urbanization and grassland desertification in northwest Liaoning,the regional diffusion of desertification area can be restrained,and the overall desertification form can be reversed and the ecological situation of the future basin is improved obviously.