The kinetics of leaching of nitrate (NO3−) in agricultural and non-agricultural soils was studied on undistributed columns using alkaline soil (pH = 8) of Kota region of Rajasthan. Potassium nitrate (KNO3) was used as a source of NO3−. Power form equation (LRobs = k [NO3−]i1.49 for agricultural and (LRobs = k [NO3−]i1.72 for non-agricultural soils) have been derived for dependence of LRobs on leachable concentration of NO3− present initially in the column during leaching. Effects of pore volume, temperature, Ca hardness and Na level of extractants have been observed on leaching rate. Change in water filled porosity θ (cm3 cm−3) of the column has been found to affect LRobs. An increase in temperature in the range 25–50°C has increased LRobs. Experimental data fitting on various kinetic models showed first order kinetic models and parabolic diffusion to be most suited for predicting leaching rates.
Nitrate, agriculture, adsorption, desorption, leaching kinetics, and kinetic models
