| Qingyun country of Dezhou is taken as the research areas in this study.Fieldsurveys and sampling were conducted in April and November of2011to collectwater and soil samples and record vegetation and land desertification situation;The TM remote sensing data of1989,1995,2000,2005,2011in the study areawere analyzed by ENVI. Visual interpretation and supervised classification wereproceed combining the investigation object information to extract the informationof the land type and desertification distribution, and GIS was used to research thetransfer matrix of land-use type and dynamic change; Indoor experiment wasemployed to study the field samples in order to get the8ions of the soil. Depthstatistical and correlation analysis of soil ions and salt contents were carriedthrough by SPSS, and spatial variation study of sand salt content was worked byusing GIS; NDVI index of study area was calculated to obtain the index ofdesertification degree, and on the basis of this, the landscape pattern wasanalyzed; The desertification future trend in Qingyun country was protected basedon Markov method. By analyzing and integrating the factors which affecteddesertification such as groundwater depth and salinity, geographical and climate,the Yellow River network and human factors in study area, control plan for thedesertificated land in study area was put forward. The results showed that:1．The trend of Qingyun country land-using type transformation was: themain transfomation type of the arable land was mild sandy land and other land(especially for construction). Forest land was mainly converted to arable land,other land was translated to arable land and the main transformation types of mildsandy land were arable land, severe land and other land. The area of local sand hasincreased and the arable has converted to13.1km2of varying degree sandy landsince2005. The main reason for this was that because of natural andanthropogenic effects, the erosion of local land has accelerated which then lead tosome middle and low cover arable land degraded to sandy.2．The average soil salt content of the study area ordered from shallow todeep were2.648g/kg,2.646g/kg,2.637g/kg,2.446g/kg and2.536g/kg whichmainly presented a falling trend. The maximum was3.717g/kg which appeared inthe80～100cm and the minimum was1.246g/kg of40～60cm. This could reflect the regional saltness differences in different sandy soil. Local land desertificationand salinity showed a similar geological law of spatial distribution and the degreeof spatial variation increased from east to west. For the area containing higher saltcontent, there was a greater risk to happen secondary salinization, its plantingcondition was worse, texture was more loose and was easily to translate intosandy soil because of the verosive effect of wind erosion.3．It could be seen from the distribution of soil degradation changes in1989～2011that there was a trend of turn for the better on the whole and particalworse degeneration in Qingyun country,desertification index dropped from7.58in1989to3.99in2005; The Markov model was used to predict the structure offuture land use. It showed that: arable land would still be the main use land in thestudy area, when the proportion of desertified land reached to12.37%, thestructure would be stable.4．By the qualitative analysis of the driving force of land desertification, itcould be known that the human factors still dominated the sand erosion processesof the study area in addition to the natural geography, groundwater and Yellowfactors. Based on the above conclusions, local governments could adjust the landuse structure, achieve the agroforestry and crop cooperation, create economicforest, improve present models of soil erosion, and at the same time, strengthenthe construction of modern water network in order to gorven the desertificationfundamentally. |
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