基于隶属度函数和因子分析的赤松人工林土壤肥力综合评价

Comprehensive Evaluation of Soil Fertility of Pinus densiflora Plantations Based on Membership Function and Factor Analysis

以胶东丘陵区15块典型赤松人工林样地为对象,通过野外取样和室内分析,采用隶属度函数和因子分析方法综合评价了赤松林地的土壤肥力。首先选取5个土壤养分指标和8个土壤物理和化学环境指标,建立了S型和抛物线型隶属度函数,分别计算出隶属度值;然后运用因子分析确定了各项指标的权重;最后运用加乘法则计算出土壤综合肥力指数。结果表明,赤松林地土壤肥力指标间的相关性较强,除土层厚度外,其它12个指标间均存在较强相关性,表明土壤养分状况和物理化学环境均会对赤松人工林地土壤肥力产生较大影响。不同样地间的土壤综合肥力存在较大差异;昆嵛山林场的土壤肥力指数最大,显著高于其它3处林场;神童村、风云林场和曲村赤松林地的土壤综合肥力之间没有显著性差异。相关分析表明,林龄与综合肥力指数之间存在显著正相关,在林龄较高时,林地土壤综合肥力高于低龄赤松林地,而林分密度对林地综合肥力没有产生显著影响。

Taking 15 typical sample plots of Pinus densiflora plantations in hilly area of eastern Shandong province as the research object,the comprehensive soil fertility of P.densiflora plantations with different age and density was studied by means of membership function and factor analysis.Firstly,five soil nutrient indexes and eight soil physical and chemical environmental indexes were selected to establish membership functions of S-type and parabolic type,and the membership values were calculated respectively.Then the weight of each index was determined by factor analysis.Finally,the soil comprehensive fertility index was calculated according to the method of addition and multiplication.The results showed that there was a strong correlation between the soil fertility indexes of P.densiflora plantation,and there were close correlations between the other 12 indexes except the thickness of soil layer,which indicated that the soil nutrient status and physical and chemical environment would have a great impact on the soil fertility of P.densiflora plantation.There are great differences in soil comprehensive fertility among different plots.The soil fertility index of Kunyushan forest farm was the highest,which was significantly higher than the other three forest farms.There was no significant difference in the comprehensive fertility of P.densiflora forests among Shentong village,Fengyun forest farm and Qu village.There was a significant positive correlation between stand age and comprehensive fertility index.At higher stand age,soil comprehensive fertility of forest land was significantly higher than that of low-age P.densifloraa forest land.However,stand density had no significant effect on comprehensive fertility of forest land.