2007/07/01 by Mushtaq Ahmad Wani, Samar C. Datta, Samar Chandra Datta
Materials Science · Engineering · Energy · #Clay minerals and soil interactions #Soil and Unsaturated Flow #Iron oxide chemistry and applications
paper · doi:10.1097/ss.0b013e31804fa26a
Kinetics of potassium (K) release from some soils and their fractions in relation to diffusion parameters was investigated by equilibrating the soils and their fractions with chloride-free H+ resin for periods of 0.25, 0.5, 1, 2, 5, 10, 25, 50, 100, and 200 h. Diffusion of applied K was estimated by employing half-cell technique. Potassium released to H+ resin after 200 h of equilibration was 0.78, 0.49, and 0.55 cmolc kg−1 for the selected soils of high-, mid-, and low-altitude zones of the Lesser Himalayas, respectively. Potassium released from silt fractions did not vary much among the three zones. Nonexchangeable K released from clay fraction at 0.77 to 1.11 cmolc kg−1 was higher in the soils of the high-altitude zone. The rate of nonexchangeable K release was faster for first 5 h of reaction period, and thereafter, it leveled off with time. The value of diffusion coefficients ranged between 8.01 × 10−8 to 4.33 × 10−7 cm2 sec−1 in these soils. The diffusion coefficients were large where the exchangeable K contents in soils were higher.