The pHof all soil sampleswas determined in 1:1mixtures of dry pulverized soil and distilledwater (Thunjai et al., 2001). The organic carbon concentration was also determined by sulfuric acid-potassium dichromate digestion (Walkley–Black method) described by Nelson and Sommers (1982).
The pHof all soil sampleswas determined in 1:1mixtures of dry pulverizedsoil and distilledwater (Thunjai et al., 2001). The organic carbonconcentration was also determined by sulfuric acid-potassium dichromatedigestion (Walkley–Black method) described by Nelson andSommers (1982).