改进AHP模型在黄土高原沟壑区土壤质量评价中的应用——以陕西省长武县耕地为例

本文以位于黄土高原沟壑区的长武县作为研究区域,选取与土壤质量密切相关的土壤有机质,易氧化有机质,全氮、碱解氮、全磷、速效磷、速效钾、微量元素、土壤酶活性、粘粒、阳离子交换量等因子作为评价指标.采用指数标度法确定判断矩阵,对传统层次分析模型进行了改进,确定了权重系数,利用模糊数学中的综合指数法计算土壤质量指数.结果表明,以指数标度法作为改进应用干层次分析模型,建立了有效的递阶层次分析结构,避免了判断矩阵一致性检验的过程.与用偏相关系数确定权重相比,层次分析模型使土壤质量各指标的权重区分度更加明显,避免权重平均化的趋势.根据两种权重得出的土壤质量指数进行方差检验(P=0)的结果存在显著性差异.评价结果显示,长武县土壤质量受地形部位影响较大,土壤质量指数分布在0.19～0.71之间,有75-2%的土壤质量处于中等水平,有17.9%的土壤质量处于贫瘠状态.

Application in Soil Quality Evaluation on Improved AHP (Analytic Hierarchy Process) Model of Loessial Gully Region A Case of Changwu County in Shaanxi Province

Changwu County was chosen as the research area at the Loessial gully region. Selected soil physical and chemical properties and soil enzyme activity was taken as evaluating indicators which was closely related to soil quality, such as soil organic (SOM) matter, total N, alkaline N, total P, available P, available K, trace element, soil enzyme activity, clay content, and cation exchange capacity(CEC). The traditional analytic hierarchy process (AHP) was improved through establishing comparison matrix by adoption of a new exponent scale. The weight values were determined for each evaluating indicator. Finally, the calculation of soil quality index was obtained by comprehensive indexing method of fuzzy mathematics. The results indicated that the process of consistency test to the comparison matrix was avoided by the establishment of effective hierarchical analysis structure in which a new exponent scale was applied as an improvement of traditional AHP. The weight values of each indicator determined by AHP model more significant than that gotten by partial correlation coefficient model whereby ignored equalization trend of weight values. Variance test indicated that there was a significant difference between weight values determined by the two models. Evaluation results implied that Changwu soil quality was significantly impacted by topographic positions. Furthermore, soil quality index ranged from 0.19 to 0.71, while medium level accounted for 75.2%, and about 17.9% of the state of soil quality is poor.