Availability Indices of Boron in Tropical Acidic Rice Soils

Characterization of major soil groups of Kerala with respect to their boron (B) supplying power has been done using azomethine-H method. Fractionation study was conducted to quantify the major fractions contributing to B fertility. Adsorption studies were also conducted to find out B adsorption pattern of selected soils by using quantity/intensity factors. Fifteen soils out of the 25 soils under study had hot water extractable B content less than the critical limit (0.5 mg kg-1). Non-specifically adsorbed plus water soluble fraction (NSA-B) and Mn-oxy hydroxide fraction (MOH-B) contributed to the plant available pool. Adsorption of B for 22 soils could be described by Freundlich equation.