Adsorption-Desdrption of Imidacloprid on Five Tropical Indian Soils

Adsorption-desorption of imidacloprid on five Indian soils of different origin was studied using batch equilibration technique. Freundlich's constant K_f-ads was highest for alfisol soil (7.81) having high organic carbon content and low pH. Adsorption was in the order alfisol (7.81) > vertisol (4.72) > oxisol (3.08) > ultisol (1.96) > inceptisol (0.88). Imidacloprid showed L type isotherm curve (1/n < 1) in all soil types except inceptisol, indicating high affinity of it towards soils. Desorption studied at 200 μg g⁻¹ concentration showed that imidacloprid binding to soil is weak and significant amount of it can be desorbed from all soil types.