| There are high altitude , low air temperature , drought, strong wind characters in High Frigid Regions in China . The area of desertificational land is about 313.28 thousand km2, account for about 11.95 percent of the total desertificational land in China , most distribute in Qing-hai and Tibet provinces (or regions). The desertificational land is in development to fierce development state due to human's unreasonable uses of land resources , and it has been the encumbrance to region economy development . This paper carried through systematical research on sandy desertificational land in High Frigid Regions of China . Took Sha-zhuyu and east shore of Qing-hai lake as the examples and based on the mass of field survey and soil analyse, took comparative method, we carried through the researches on the causes of the desertification , the origin of sandy desertificational land substance , the development diversification and difference of soil characteristic in process of manual and spontaneous vegetation recovery in High Frigid Regions and make out the taxonomy of desertificational land in High Frigid Region of China. The result obtained are summarized as follows:1. The development of the desertificational land in High Frigid Regions is caused by the manual and spontaneous factors . The blow sand soil are came into being locally in Sha -zhuyu area, but it was transported from west shore by the strong wind in the east shore of Qing-hai lake. The development of desertification is still fierce in these two regions .2. Because of feeble development, sandy desertificational land in High Frigid Regions of China have higher sands content, which is commonly larger than 750g/kg, there are also higher SiO2 correspondingly , which is commonly larger than 600g/kg . There are higher potassium and calcium carbonate content, larger pH , lower organic matter , nitrogen and phosphoric . Compared sandy soil with zonal soil , mechanical composition is coarsal , there are no substance leaching.3. In the process of manual vegetation recovery of blown sand soil, coarse sands (l-0.25mm) content gradually lower , middle sands (0.25-0.05 mm)no changes, fine sands(0.05-0.02mm), silt, clay content gradually become higher in mechanical composition. Soil organic matter, CEC, nutrient content gradually higher, and pHvalue, calcium carbonate content gradually lower. SiO2 gradually reduce, other elements gradually higher in soil mineral element, and all elements have no transfer phenomena in soil body. Soil begin development from surface layer. The transformation of soil physical and chemical characters is higher in surface layer than underlayer. With the enhancement of soil development degree, the difference in each physical and chemical characters arelarger.4. In the process of spontaneous vegetation recovery of blown sand soil, coarse sands (l-0.25mm) content gradually lower, middle sands (0.25-0.05mm) and fine sands (0.05-0.02mm) ,silt ,clay content gradually higher in mechanical composition. The development pace is larger in surface layer than underlayer in the process of spontaneous vegetation recovery. But the transformation of physical and chemical characters is instable because of always interrupt or repeat of soil development process. Compared manual with spontaneous vegetation recovery process of blown sands, the pace is quicker, the degree is higher, the transformation range is larger of every physical and chemical characters.5. Based on the method from 《Keys to Chinese Soil Taxonomy (3rd edition)》, there are five Diagnostic horizons, six Diagnostic characteristics, Primosols ,Cambosols and Isohumosols three orders , three suborders , six groups , seven subgroups in research regions.6. The climax development group is Isohumosols after sandy soil fixed under vegetation recovery condition in research regions. There was no different in soil type after 40 years developed. This manifested that soil formation and development process is very slow in High Frigid Regions .
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