基于云模型的耕地土壤养分模糊综合评价

Fuzzy Synthetic Evaluation of Soil Nutrients in Cultivated Land Based on Cloud Model in Da'an City,Jilin Province

土壤养分综合评价在很大程度上存在着模糊性和随机性,为有效解决评价中定性概念与评价指标按隶属函数定量描述这一不确定转换问题,基于云理论及模糊数学原理,构建了基于云模型的耕地土壤养分模糊综合评价方法。以吉林省大安市为研究对象,选取耕作层中有机质等7个土壤养分元素的含量作为评价指标,利用熵权法确定各指标权重,计算得到评价对象的土壤养分模糊云综合指数(Cloud fuzzy comprehensive index,CFCI),并对CFCI进行COK插值,形成土壤养分CFCI等级分布图。结果表明:从评价结果的数据特征来看,研究区域CFCI范围在2.43~4.89之间,平均值为3.78,标准差为0.45,变异系数为11.85%,属于中等变异程度;从评价结果的空间分布格局来看,大安市耕地土壤养分综合水平呈现由北向南逐渐下降的趋势,且呈现耕地集中连片度越高的地方,土壤养分综合水平越高的特点。

There are randomness and fuzziness to a large extent in soil nutrient synthetic evaluation. In order to effectively solve the uncertain transformation problem between the qualitative concepts and evaluation indexes,which are described by membership function,based on the cloud theory and fuzzy mathematics theory,a fuzzy synthetic evaluation method was presented based on the cloud model. Taking Da＇an City in Jilin Province as the research object,totally 7 soil nutrient elements contents were selected such as organic matter in the cultivated layer as evaluation,and the weight of each index was determined by using entropy method. The cloud model was applied to the comprehensive evaluation of soil nutrients,and the soil nutrient fuzzy comprehensive index of each evaluation unit was obtained（cloud fuzzy comprehensive index,CFCI）. In addition,COK was used to get the interpolation of CFCI,and a distribution map of soil nutrients CFCI grade was formed. The results showed that the evaluation results from the data characteristics of the study area,CFCI was in the range of 2. 43 ~ 4. 89,the average value was 3. 78,the standard deviation was 0. 45,coefficient of variation was 11. 85%,which was in moderate degree of variation; from the perspective of spatial distribution pattern of the evaluation results,the comprehensive level of soil nutrients in Da＇an City was decreased gradually from north to south,and the higher concentration of cultivated land was,the higher the level of soil nutrient comprehensive was.