改进的突变模糊隶属函数法对公乌素土壤肥力质量评价

An improved Method of Catastrophe Fuzzy Subordinate Function and its Application in Soil Quality Evaluation

关于土壤质量评价的方法有很多,如层次分析法、模糊评价法、主成分分析法等,然而这些方法普遍存在着主观"权重"问题。基于此,将突变理论和模糊数学相结合产生出的突变模糊隶属函数法应用到土壤质量评价中,对公乌素引洪淤地后改良土壤肥力进行评价,与层次分析法进行了比较。结果表明:其评价结果基本一致,论证了突变模糊隶属函数法的可行性;此方法一个特点是不需要确定权重,它是计算矛盾的一种方法,是把评价指标看成是矛盾的主要方面和次要方面,本质是运用归一公式把系统内的诸矛盾方面(评价指标)不同质态的矛盾转化为同一质态。此方法很大程度上减少了人为的主观性问题;同时,与传统方法相比,突变模糊隶属函数只需要确定各评价指标的相对重要性程度排列顺序,减少了人为的主观性问题;计算量小,便于应用;模型应用相对简单,不需要知道特殊的内部机制。

There are many methods for soil quality evaluation, for example, analytic hierarchy process, fuzzy evaluation method and principal component analysis method. However, they are often subjective in determining the weights of influencing factors. In this paper, the catastrophe theory and fuzzy mathematics were combined to produce the catastrophe fuzzy subordinate function method, which then was applied to evaluate soil fertility after muddy water irrigation in the Gongwusu area. It was compared with the improved AHP. The results showed the consistence of the two methods. The evaluation results demonstrated high feasibility and efficiency of the catastrophe fuzzy subordinate function method, which does not need to determine the weights and the importance of each indicator depends on its intrinsic contradiction status and mechanism. Its essence is to calculate contradiction(index) of different qualitative state, largely reducing the subjectivity in determining the weights. Compared with the traditional method, the presented method is simple in computation and easy to master.