Effect of heavy metal and nutrient uptake by soils in Indian Cardamom Hills

Abstract

Indian cardamom hill soils were studied to understand nutrient and heavy metal uptake and consequent fertility level changes. Extensive cultivation of cardamom and conversion of forest land to cardamom agriculture resulted in decline of OM and lower pH. Application of chemical fertilizers in the recent past helped enhance the available phosphorus (P). This is surprisingly contrary to the general observation of low P fertility and availability of tropical humid forest soils. Available nutrient concentrations with respect to potassium (K), magnesium (Mg) and sulphur (S) were low in cardamom soils while micronutrient concentrations were well above the proposed critical limits. Agricultural intensification through use of mercurial fungicides and other pesticides in Indian cardamom hill soils has resulted in continuous loading of heavy metals in leaves, seeds and rinds. Such a situation could soon lead to a level sufficient to cause serious fertility and environmental problems. Key words: Nutrient and heavy metal uptake, soil fertility, tropical agro forest environment.