Immediate Quantity-Intensity Relations of Potassium and Sodium in an Alluvial Soil

Q/I studies of labile potassium and sodium of an alluvial field soil revealed three exchange sites for potassium, viz, planar, edge and interlattice, which differed remarkably with regard to their preference for potassium adsorption. The planar exchange sites were equally accessible to potassium and calcium while edge and interlattice sites showed a high degree of specificity for potassium adsorption. Most of the exchangeable sodium was loosely bound and could be replaced easily by calcium. However, at low activity ratio of sodium, a small amount of sodium was also present at specific adsorption sites. The method of fractionation of immediately exchangeable potassium and sodium are described.