Soil and leaf potassium, calcium and magnesium in oil palm (Elaeis guineensis Jacq.) plantations grown on three different soils of India: Status, stoichiometry and relations

Abstract

The knowledge pertaining to phyto-availability of potassium (K), calcium (Ca) and magnesium (Mg) in soils and K, Ca and Mg concentrations in plant tissues and their relations in different productions systems of the world is limited. Understanding soil and leaf K, Ca and Mg concentrations and their stoichiometry in oil palm (Elaeis guineensis Jacq.), a globally demanding crop for vegetable oil production, is important for efficient K, Ca and Mg management. We, therefore, collected soil and leaf samples from oil palm plantations (OPP) established on three different soil series of India, and analysed to assess soil properties (pH, electrical conductivity, soil organic carbon) and concentrations of exchangeable K (Ex. K), Ca (Ex. Ca) and Mg (Ex. Mg) in soil and leaf K, Ca and Mg concentrations and their stoichiometry, and to visualize their relations. Soil properties, concentrations of Ex. K, Ex. Ca and Ex. Mg and their ratios in OPP of different soil series varied widely and differed significantly. The mean concentrations of Ex. K, Ex. Ca and Ex. Mg in OPP of Jangareddigudem and Madukkur series followed the order: Ex. Ca > Ex. Mg > Ex. K. However, soils of OPP of Karmali series had higher mean concentration of Ex. Ca followed by Ex. K followed by Ex. Mg. Leaf K, Ca and Mg concentration and their ratios in oil palm plantations of all the three-soil series varied widely and differed significantly. The mean concentrations of leaf K, Ca and Mg followed the order: Ca > K > Mg. There were positive and significant correlations of Ex. K with Ex. Ca in soils of Jangareddigudem and Madukkur series. Leaf Ca concentration was negatively and significantly correlated with leaf K concentration and Ex. K and Ex. Mg in soils of Jangareddigudem series. There were no correlations of leaf K, Ca and Mg concentration with Ex. K, Ex. Ca and Ex. Mg in soils of Madukkur and Karmali soil series. This study highlighted the need for maintaining equilibrium concentrations of Ex. K, Ex. Ca and Ex. Mg in soils for ensuring proper K, Ca and Mg nutrition of oil palm.