Competitive adsorption and Interaction of Cu, Zn, Pb and Cd in coffee growing soils of South India

摘要

Coffee growing soils receive trace metals like copper, zinc, lead and cadmium either through agro-inputs like fertilizers, urban compost, sewage sludge etc., or through plant protection chemicals like fungicides/herbicides. The extensive use of such inputs over long periods leads to accumulation of nutrient as well as toxic elements in soils. The presence of one element in excess can affect the uptake of the other and result into imbalance in supply of essential nutrients to the standing crop in thatsoil. Hence to understand the interaction of nutrient element like copper with another nutrient, zinc and two toxic elements, viz., lead and cadmium, batch equilibration study was taken up in coffee growing soils representing four major states of southIndia. The variation in adsorption pattern and sequence of affinity in binary systems was studied. The data indicated that the presence of any other element reduced the quantum of adsorption of copper in all the four soils (Balehonnur, Thandigudi, Chundale and R V Nagar) compared to that in a solitary system. The affinity sequence for the elements was Pb > Cu > Zn > Cd in majority of the soils while that for Chundale soils was Cu > Pb > Zn > Cd.