Determining the Role of Leaf Relative Water Content and Soil Cation Exchange Capacity in Phytoextraction Process: Using Regression Modelling

Abstract

Cation exchange capacity (CEC) is defined as the total capacity of soil to hold exchangeable cations. Some of the major nutrients that plants uptake from soil are transported from soil to plants in the form of cations only, such as Ca²⁺, Mg²⁺, K⁺, Na⁺, H⁺, Al³⁺, Fe²⁺, Mn²⁺, Zn²⁺, and Cu²⁺. Therefore, it is very important to study the interlinking factors responsible for nutrient transport in plants. Our study here aims at establishing a correlation between soil CEC and leaf RWC of the mining area. For this purpose, soil samples were collected from six different sites in and around Rajrappa mines with each site having two replicate samples to determine the CEC of the soil, soil texture, and soil pH. Leaf samples were also collected from all the sites subject to their availability in each site to determine relative water content (RWC) and pH of the plant leaves. The soil samples range from sandy soil to sandy clay loam in texture, and soil pH ranges from slightly acidic to neutral. The CEC values were found to be below 15 meq/100 g of soil samples for all the sites except for two samples taken from forest stand beside the mine where it was observed to be 26 meq/100 g. The RWC values range from 29% in lowest seam mining surface plants to 87% in reclaimed OB dumpsite. Using Minitab software, a correlation was drawn between soil CEC and leaf RWC in purview of soil texture. It was observed that there is a significant positive correlation between soil CEC and leaf RWC. A high value of CEC clearly suggests a value of leaf RWC. Moreover, in contrast to soil texture, it was clear that the presence of coarser soil particles reduces the soil CEC values and thus also reduces the leaf RWC values. However, no significant correlation was observed between plant leaf pH values and other factors.