Adsorption, Desorption and Movement of Endosulfan in Agricultural Soil

The effect of soil properties like adsorption, desorption, movement and distribution of endosulfan (1, 2, 3, 4, 7, 7-hexachlorobicyclo (2, 2, 1)-2-heptene-5, 6-bisoxymethlene sulfite) in two tropical soils, sandy loam and sandy clay soil from Mysore, Karnataka state were studied respectively. The results indicated that soils with different physico-chemical properties have different effects on the adsorption, movement and distribution of pesticide, especially at higher concentration levels. Two composite soil samples were collected that having diversified physico-chemical properties were analysed. Adsorption coefficient values (K ads) as described by Freundlich’s model ranged from 0.04 to 0.31. Higher adsorption coefficient was measured in Halekesare soils as compared to Hinkal soils. Desorption as attributed to hysteresis was also measured. Desorption coefficient values (K des) were higher than adsorption (K ads) in each study. Movement of endosulfan was restricted to subsurface soil upto 0-15 cm depth only in both the soil types. However, vertical movement of endosulfan was faster in sandy loam soil than sandy clay soil. Results indicated that applied endosulfan retained in the upper layers of soil would be persistent or slow to degrade in the soils studied.