|Other Abstract||A study on soil quality under artificial shelterbelt irrigated highly minealized water in Desert was carried out in an effort to understand the characteristics and assessment. It indicated the soil physics, chemistry, biology and other associated process. Special attention was on the improvemnt of atifical shelterbelt to Aeolian sandy soil, the sustainable development of artificial shelterbelt in arid areas and the relationship between sandy soil and people. In this research, the atifical shelterbelt in Taklimakan Desert had long-term highly mineralized water with drip irrigation. Through field investigation sampling, indoor soil analysis, combined with mathematical statistics, basic characteristics of the soil quality with different plantation ages, different mineralized of irrigation water and different plant species were studied. Soil quality assessment indicators were screened and soil quality comprehensive assessment model was established. Soil quality in Taklimakan Desert with long-term highly mineralized water drip irrigation was assessed. Main results for this study are as follows:
⑴ After planting artificial shelterbelt, the change of soil mechanical composition first occurs on the surface, fine sand content reduced, fine sand, coarse silt and fine silt increased. Except total potassium, pH, electric conductivity, nutrients and enzymatic activities had a strong “suface gathering”. Soil properties in the surface layer had the strongest variabilities. It was the representative of the change of shifting sand soil to the semi-fixed and fixed sand soil.
⑵ Age of the forest had same influence on surface soil quality indicators of different species. With forest age increasing, fine sand content reduced, fine sand, coarse silt content, pH and electric conductivity increased. In addition to total potassium, the other soil nutrient content increased, and the activities of urease and catalase, the content of microbial biomass carbon and nitrogen all significantly increased.
⑶ Highly mineralized water had different influence on soil quality indicators. As the salinity of the irrigation water increasing, soil texture of Tamarisk L. coarsed, while soil mechanical composition in Calligonum L. and Haloxylon L. plantation had no significant change, no significant changes in pH, but electric conductivity increased, tamarisk and Calligonum soil nutrients increased, increasing soil available K and cation exchange capacity Haloxylon forest, and the rest after the first increase to reduce nutrient indicators, microbial biomass carbon and nitrogen content of significantly reduced. When the drop irrigation salinity is 2.88 ~ 12.07 g L-1, the plantation urease and catalase activity increased with the increase of salinity drip irrigation is enhanced when the drip irrigation salinity 12.07 ~ 29.70 g L-1, when Haloxylon plantation enzyme urease and catalase activity with drip irrigation increased salinity weakened.
⑷ Nineteen soil quality indicators were analyzed, we screened out eight soil quality indicators：the total amount of aggregate, the total amount of water stable aggregates, available nitrogen, urease, microbial biomass nitrogen, total phosphorus, available phosphorus and potassium, quality comprehensive assessment index system with highly mineralized water irrigation in forest soil was established.
⑸ Following soil quality classification standard, with forest age increased, soil quality grade of three plant species increased, Haloxylon and Tamarix Calligonum relatively more beneficial to Aeolian sandy soil quality improvement. Different salinity water irrigation on the performance of soil quality index is: When irrigation water salinity ≤23.08g L-1, the soil quality index is not significantly affected, when the irrigation water salinity＞23.80g L-1, Haloxylon plantation soil quality index significantly decreased.|