Herbicides Soil Kf (mg/Kg ) 1/n R2 Koc(mg/kg) Kom (mg/kg ) Hysteresis index Simazine A 0.5717 0.4738 0.9957 6.6476 4.1729 0.315 B 0.4979 0.4940  0.9814 23.7095 10.3729 0.658 Atrazine A 0.5238 0.4043 0.9936 6.090 3.8233 0.525 B 0.6780 0.3015 0.9774 32.285 14.125 0.950

Table 4: The desorption parameters of simazine and atrazine in the soils.