Adsorption and desorption characteristic of benzimidazole based fungicide carbendazim in Pakistani soils

A versatile cost-effective benzimidazole based fungicide,carbendazim (methyl 1hbenzimidazole- 2 carboxylate ) has been utilized to investigate its sorption-desorption behaviour on physicochemical properties of geographical soils,ranging from hilly to desert areas of pakistan,via batch equilibrium method. the data obtained in all tests showed that adsorption co-efficient isotherm for carbendazim in four tested soil were well fitted the freundlich equation. distribution co-efficient (kd ) parameters are low (3.59 to 11.60 ml μg-1) indicating low adsorption. it was observed that carbendazim showed a relatively greater degree of adsorption on soil samples (soil 4) that were collected from northern hilly areas ayubia,khyber pakhton khaw (kpk) (silt loam) i.e.11.60 ml μg-1 and least adsorption on sandy soil of multan punjab(soil 2). while other two soils 1 were collected from murree region,a boarder of punjab & kpk mountain area and soil 3 from tarnol,islamabad. desorption studies reveal that the adsorbed fungicide is firmly retained by soil particles and their adsorption are almost irreversible. the results indicate that soil organic matter (som) and appropriate ph also play key role in sorption capacity.