| Investigation and evaluation of regional soil salinization is of great significance inknowing the change rules of soil salinization, preventing soil degradation and the promotingsustainable agriculture’s development. In this paper, taking desert area of Manasi river basinas the research object, researchers use the combined method of field sampling, analysis ofexperimental data and remote sensing image interpretation. Through interpretation ofremote sensing image in three different periods, researchers discuss the changing situationof land use/land cover on a regional scale and the temporal and spatial evolution of theland; with the help of land use statistics, GIS spatial analysis and fuzzy comprehensiveevaluation, researchers carry out the analysis, processing and modeling of field samplingdata in order to reveal the spatial variability of soil salinity and to provide certain theoryreference and scientific basis for evaluation, utilization and improvement of regional soilsalinization. The main research achievements are:1. Spectral characteristics of saline soil with differdent water and salt content: Therelations between soil salinization level and soil spectrum were analyzed: That obtainedsensitive bands of347-377nm and1800-1911. Changes of spectral reflectance in soil underthe different condition of texture, water and salt content were studied. Spectral reflectanceof different texture soil was as follows: Clay>silty-clay-loam> sandy loam. Soilsalinization degree is heavier, the higher the spectral reflectance values. Reflectancespectrum curve of different texture soil had the critical value of field moisture capacity,when soil water content was higher than field capacity, and the reflectivity increased withsoil moisture; reflectivity decreased with the increase of soil water content below fieldcapacity.2. Iinversion based on Remote sensing Soil salinization in the studyarea：The relations of salt content data and salt index on april26,2009TMimages is: y=0.093+0.766x. accuracy of87.34%. There is accounted for57.02%unsalinization soil in the study area, by remote sensing inversion,mild-salinization soil area of18.7%, moderate salinization and severesalinization area accounted for24.28%. The total soil salt reserve in Manas riverbasin0to30cm soil is about2.2x109tons.3. Land use/cover survey in Manas river valley: By interpretation and analysis ofremote sensing images in three different periods of1989,2001,2012, researchers concludethat construction land boom, woodland, grassland area increase, unused land area isshrinking, the water area steady, cultivated land has also been on the rise in the pasttwenty-three years with human activity. The results of arable land using the decision treeclassification show that the degree of cultivated salinization land with the passage of timegradually weakened, the unsalinization cultivated area of31.58%, mild salinization ofcultivated land area of23.02%, moderate salinization and severe salinization area accountedfor45.39%. 4. Saline soil utilization potential evaluation: soil organic matter, available nitrogen,available phosphorus, available potassium, pH value, total salt content and groundwaterdepth of sampling are tested by investigation and analysis on the desert oasis in Manasifield, researchers successfully constructed the saline-alkali land use potential evaluationmodel, and by using interpolation in ArcMap9.3analysis, the study area land use potentialspatial distribution map and four class risk area diagram of the comprehensive evaluationare made. The secondary utilization potential area above the saline-alkali soil of study areaaccounted for72.68%of the total area.From this research we would get lots of scientific help about soil salinity treatment&improvement，agriculture planning&adjusting, and irrigation and drainage engineeringplanning in the future. |
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