ABSTRACT
The behavior of simetryn and thiobencarb in flooded rice soil was investigated in a 2-year study. The concentrations of simetryn and thiobencarb were in the hundreds of µg kg−1 in the top soil layer (05 cm) and became significantly lower in tens of µg kg−1 in the deeper soil layers (510 and 1015 cm). The half-lives of the two herbicides were also shorter (36 and 17 days for simetryn and thiobencarb, respectively) in the top soil layer, as they were most affected by environmental conditions, compared with corresponding values of 82 and 69 days in the 510 cm soil layer. Simetryn concentration was stable, while thiobencarb's half-life was 165 days in the 1015 cm layer. About 35% of the applied mass of simetryn and thiobencarb were found in the rice soil compartment.
