The degradation of imazapyr in four soils was investigated under laboratory aerobic and anaerobic conditions. Under aerobic conditions, imazapyr degraded faster in yellow-red soil than in other soils, and its persistence decreased depending on soil pH in the order coastal soil (pH 8.8) >silt-loamy paddy soil (pH 7.9) >fluvio-marine yellow loamy soil (pH 7.1) >Yellow-red soil (pH 5.3). However, soil pH did not affect imazapyr degradation under anaerobic conditions. The half-lives of imazapyr in soils under aerobic conditions were in the range of 26-44 days estimated by the first-order ...
