偏最小二乘回归方法提取土壤质量单项评价指标初探

Extraction of Single Soil Quality Index by Partial Least Squares Regression Method

研究农田土壤属性动态变化,提取土壤质量单项评价指标,可为改良土壤环境提供指导。在黑河上游典型农田随机采集64个土样,测定土壤含水率(θ)、电导率(EC)、滴水穿透时间(WDPT)、饱和导水率(Ks)、黏粒(CL)、粉粒(SI)、砂粒(SA)质量分数等7个指标后,将这7个指标逐个作为评价对象,与剩余土壤指标变量进行偏最小二乘回归(PLSR)分析。结果表明,1相较于主成分分析方法,利用PLSR方法筛选敏感土壤指标所构建的土壤质量评价指标适用性更强。2在构建土壤持水能力或积盐程度评价指标时,CL、SA、SI和WDPT是敏感指标,其中WDPT作为重要评价指标,需要考虑纳入到土壤质量评价体系之中。3EC与其他指标的PLSR分析指出,表层土壤积盐程度很大程度上受土壤持水能力影响,但积盐程度却不是决定土壤持水能力的主要因素。

In order to find a way to improve soil environment, the single soil quality evaluation index was extracted which combined completed raw data by studying the dynamic change process between different farmland soil properties. 64 cultivated land samples were random collected in the upstream of Heihe River. Soil water content （0）, electrical conductivity （EC）, water drop penetration time （WDPT）, saturated hydraulic conductivity （Ks） and clay （CL）, silt （SI）, sand （SA） mass fraction were analyzed. Every indicator was assumed to be one soil quality evaluation object for partial least squares regression （PLSR） analysis with the residual soil indicators. The results showed that： （1）Compared with the PLSR method and PCA method, the evaluation index of soil quality which built by PLSR method was more suitable. （2）During the process of building evaluation index for soil water-holding capacity and the degree of salt deposition, CL, SA, SI and WDPT were sensitive indexes, WDPT should be taken into the evaluation system of soil qual- ity. （3）PLSR analysis between EC and other indicators pointed out that the degree of salt deposition in sur face soil was largely influenced by soil water-holding ability, and the degree of salt deposition was not the main factors to decide soil water-holding capacity.