| Salt contents in soils different in cultivation age, two vegetation coverage and fore-and-aft Freezing in Qitai County of Xinjiang were investigated for analysis of rules of the variation of soil salt content, types of soil salinity content profiles, spatial variability and their affecting factors, using the cluster analysis method and some other related methods. Analysis results:(1) Along with the transformation of wasteland into farmland (at least 5 years in cultivation history), the characteristics of soil salt content distribution in the soil profiles varied and followed the order of surface accumulation profiles (SAP), even distribution profiles (EDP), oscillation profiles (OP) and bottom accumulation profiles (BAP). The non-farmland high in salt content is typical of salinized soil, with significant phenomenon of surface accumulation; and the salt in the surface layer (0~20cm) accounted for 34.31% of that in the soil profile. The farmlands, 5 or 10 years old, mostly belonged to the category of BAP. With the farming operation going on and on, soil salt content in various salt–containing layers varied to varying degree showing an order of active layer (AL), sub-active layer (SAL) and relatively stable layer (RSL), and an extremely positive correlation between soil salt content and soil organic matter content gradually turned in an extremely negative one, while the correlation between soil salt content and soil pH went the other round. Under farming activities, soil salinization developed reversely. The average salt content in farmland 10 years old was only 20.90 percent as much as in wasteland. The desalination rate was reducing with the farming operation going on from 0.156% a-1 in the first three years of farming down to 0.004% a-1 when the farming activity went beyond 5 years.(2) The soil water and salt content of bare land and vegetation area obey log-normal distribution; soil salinity belongs to moderate variability with a strong spatial autocorrelation. Soil moisture variability in the bare land belongs to weak variability with moderate intensity of the spatial autocorrelation; vegetation area belongs to medium (weaker) variability with strong spatial autocorrelation. Bare land autocorrelation distance is about 1 / 10 of vegetation area.(3) Before the freezing, the value of soil salt content (0.11%) and electrical conductivity (0.30ms.cm-1)in topsoi(l0-20cm) is minimum, the deeper of soil depth, he higher of the value. While the complexity of soil salt content and electrical conductivity trend to decrease by the addition of the depth. After the freezing, the value of soil salt(0.38ms.cm-1)content and electrical conductivity (0.14%) in topsoil is maximum, it indicated that soil salt accumulation rate (30.0%) at the surface soil layer was significant in spring; soil salt desalination rate was obviously in fall, the average value of sections is decrease by 8.15%, the soil salt desalination depth is beyond 100 cm. In addition, spatial variability of salt content and electrical conductivity of every soil layers remained invariability, but the variance quotient gone to high.(4) Water of scientific regulation and using and maintenance of shelter-forest and cultivated land area are the basic principle of sustainable development in the research zone of oasis.
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