The loess hilly region of Changwu County in Shaanxi Province was taken as the research object. Index system of soil quality evaluation was established by screening 14 factors as the evaluating indicators, including soil nutrients, environmental factors, trace elements and soil enzyme activity. AHP was applied to work out the weight values of each factor, and comprehensive index method of fuzzy mathematics was adopted to conduct evaluation of soil quality.Based on the platform of GIS, we divided and mapped the grade distribution of soil quality of Changwu County, achieved the visualization of county-scale soil quality and had a clear understanding on the whoIe county-scale soil quality. The results indicated that soil quality of orchard is better than farmland on the same topography site and soil quality in different topography positions are in the order of table-land ＞ bottom-land ＞ slope-land. Throughout the county scale, the distribution of soil quality indexes between 0. 195 ～ 0.710 and grades Ⅲ,Ⅳ and V are only 27% of the entire area, however,grade Ⅱ is accounted for 59.7 % of the entire area. On the whole, the soil quality of the research region is at medium level and affected by topography site largely, however, the soil quality of orchard is better than farmland. Analyzing and evaluating the condition of county-scale soil quality and physical or chemical properties of soils in Changwu County provide practical and theoretical basis for land utilization and nutrient management of orchards and farmland.%以地处黄土丘陵沟壑区的陕西省长武县土壤为研究对象,筛选出包括土壤养分、环境因子、微量元素和生物酶活性等在内的14个因素作为评价指标,建立了黄土丘陵沟壑区土壤质量评价指标体系.采用层次分析法确定各指标的权重系数,运用模糊数学理论中的综合指数法进行综合评价.以GIS为平台,划分并绘制了长武县土壤质量等级分布图,实现了县域土壤质量的可视化表达,对整个县域的果园和农田土壤质量状况有了清楚的认识.结果显示:在同一地形部位上,果园的土壤质量总体上优于农田;在同一种植方式上,不同地形部位土壤质量的依次循序为塬地>河滩地>坡地.从整个县域尺度上来看,土壤质量综合指数分布在0.195～0.710之间,处于Ⅲ、Ⅳ、V等级的土壤仅占27%,而处于Ⅱ等级的土壤却占到总面积的59.7%.该地区的土壤质量状况整体上处于中等水平,受地形部位影响比较大,果园土壤质量优于农田土壤质量.对长武县土壤物理化学性质和县域土壤质量状况做了分析与评价.
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