Department of Soil Science and Agricultural Chemistry, University of Agricultural Sciences, Dharwad, Karnataka, 580005
1Present address: Dept. of Geology & Geophysics, Indian Institute of Technology, Kharagpur, 721302
A laboratory experiment was conducted to study the adsorption of added phosphorus in a Vertisol amended with different rates of wet and dry flyashes (0–30% w/w). The adsorption data were fitted to Langmuir isotherm. The phosphorus (P) adsorption maxima (b) varied greatly with the type of soil-ash mixture. Among flyashes, dry flyash had more effect on P adsorption than wet flyash. Flyashes had little effect on P desorption except at higher ash rates (20% or more). The soil-ash mixtures even though had high P adsorption capacity, because of very low bounding energy, most part of the adsorbed P was easily desorbable. Supply parameter value varied with the type of soil-ash mixture and also with the equilibrating P concentration.
Vertisol, adsorption maxima, isotherm, supply parameter, bonding energy
