乌兰布和沙漠东北部沙区人工林土壤肥力质量评价

Assessment on Soil Fertility of Planted Forests in the Northeast Sandy Area of the Ulanbuh Desert

选择乌兰布和沙漠东北部沙区9块人工林为研究对象,通过敏感性和主成分分析,筛选了16项表征土壤物理、化学和生物学特性的指标,并运用模糊综合评判法,计算土壤肥力质量综合指数(IIF)。结果表明:<0.01 mm物理性黏粒含量、团聚度、有机质、全氮、细菌数和脲酶活性构成了该区土壤肥力质量评价指标体系;所选指标能全面反映原16项指标的信息,决定系数达0.940 5;样地土壤肥力总体表现为:灌木林>乔木林>流沙地,灌木林具有较好的改土作用,柠条土壤肥力指数最高。因此,该区应以种植乡土固氮灌木为主,乔灌草结合,不宜大面积种植乔木。

In this study, the effect of vegetation on soil fertility was researched so as to guide the local vegetation construction. Nine pieces of planted forest in the northeast sandy area of the Ulanbuh Desert were taken as the study area, and 16 indicators of soil physical, chemical and biological properties were selected through the sensitivity analysis and principal component analysis to derive the integrated fertility index （I_IF） calculated with the fuzzy comprehensive evaluation approach. The content of physical clay 〈 0.01 mm, degree of aggregation, organic mat- ter content, total N content, bacterial population and urease activity were selected as the soil fertility indicators, which could reflect the most information of soil fertility, and the coefficient of determination was 0. 940 5. Holisti- cally, the value of soil fertility was in an order of shrubbery 〉 woodland 〉 sandy land, shrubbery could improve soil, and It~ of Caragana korshinskii was the highest. Therefore, the native nitrogen-fixing shrubs should be consid- ered as the dominant planted species, and some tree and herb species should also be selected, however, it is not suitable to plant trees in large area.