Desertification Assessment And Study On It's Influencing Factors In Minqin

With the development of study of desertification from qualitative examination to quantitative study。It was sure a trend of quantitative study for desertification by using some new way for reference. At the back of which, studied the soil fertility, evaluated the present situation of desertification, analyzed aspect of desertification with the extraction and condensation advance of factor analysis for index; also studied the soil texture with fractal demission and development of trend of desertification with Hurst-index.(1)The character of soil quality: It presented a different quality with the development of sand desertification or salinization in Minqin. In the vertical gradient, the first depth was higher than the second if it was not disturbed or it should present opposition by blastation, from the second to the sixth the soil quality became higher and higher until it get the best, then it should descend and the depth of the best was connected to the depth of deposition of clay. In the level space of the same depth the soil quality went down from oasis to desert and went up from South-west to North-east of Minqin. The soil texture presented main body of 0.1-1mm of coarse sand and 0.05-0.1mm of thin sand, 0.1-1mm especially, the soil dimension remain about 0.28. The soil texture was not even and the fraction of coarse and thin divided severely, but the soil dimesion was discriminating for different depth of the same spot.(2)Evaluation of desertification: Analyzed bulk weight,organic carbon,total nitrogen,electric conductivity,potential of hydrogen,vegetation cover,vegetation type,biomass,fraction of less than 1mm,0.1mm and 0.05mm,low ground water level by factor analysis from aspect of soil physical and chemical character, also from vegetation, the result showed that the South-west of Minqin included in severe sandy desertification area,light alkali-salinity in middle area and severe alkali-salinity in North-East area; There are trend of getting severe and then getting light for desertification from oasis to desert.(3)Factor of desertification: This was described in qualitative examination and quantitative study. Through analyzing of external human activities and internal human activities of using of water resource,plant protection and ways of land use,type of land use,population and graziery pressure,variance of climate in qualitative examination,draw a conclusion that the process of desertification was bodied by the action of reclaiming and cultivating,giving up cultivating,overuse of water resource; Excessive hag and overstocking was the deed of past...