Exchangeable Manganese in certain Forest Soils of India

Studies on exchangeable manganese status in fourteen profiles in widely distributed forest soils of India, differently affected by the factors of soil formation, revealed its decreasing trend with depth and wide variations in different soil groups. Forest vegetation helps in the surface accumulation of manganese through litter deposition to a certain limit. Clay content, organic matter, reaction, calcareousness and drainage appear to be important pedo-logical factors in governing the concentration of exchangeable Mn. Highly calcareous, sandy, alkaline, organic matter-rich and intensively leached soils contain smaller amounts of exchangeable Mn. Acidic soils of medium texture with moderate quantity of organic matter have a fair supply. Anaerobic conditions tend to enhance its mobilization. Within certain limits a positive relationship exists between the clay content and exchangeable Mn of the surface soils. Only a small portion of the C.E.C. of the soils is occupied by the trace element.