The persistence of pendimethalin [N-(1-ethylpropyl)-3, 4-dimethyl-2, 6-dinitroniline] and anilofos [S-[2-[(4-chlorophenyl) (1-methyl ethyl) amino]-2-oxoethyl 0, 0-dimethyl phosphorodithioate] in six tropical soils of varying physicochemical characteristics was compared under flooded and non-flooded conditions. The degradation of both the herbicides was more rapid under flooded than under non-flooded conditions in all the soils. After 30 days of incubation under flooded condition showed 36.29–78.23 and and 39.75–60.99 per cent degradation of pendimethalin and anilofos, respectively. Kinetic analysis indicated that degradation of the two herbicides followed first-order reaction irrespective of soil and water regimes. The half-life of pendimethaiin (22.6–41.8 days) was higherthan that of anilofos (13.9–30.1 days). Herbicides present in flood water showed very rapid degradation and half-life values observed in flood water were in the range of 2.5–3.4 days and 5.4–23.2 days of pendimethalin and anilofos, respectively.
Pendimethalin, anilafos, flooded and non-flooded soils, flood water, persistence
