Nitrate Leaching from Soils as Influenced by Rate and Timing of Potassium Nitate Application
2013
Sharma, Bharatiy | Rani, Ashu
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.
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