Persistence of Trifluralin and Pendimethalin in Soils Incubated at Different Temperatures

Persistence of trifluralin and pendlmethalin applied at 1.0, 1.5 and 2.0 kg ha−1 was studied under laboratory conditions in the sterilised and unsterilised field soils. Treated soil samples were incubated at 25, 35 and 45°C for 90 days in incubators. Persistence was studied by taking samples at 15 days intervals using bioassay technique with sorghum seeds as test material. Persistence of both the herbicides decreased with time and direct correlation was observed between temperature and dose i. e. lower temperature and higher dose resulted in the greater persistence in both types of soils. Persistence of both the herbicides was more in sterilised soil than in unsterilized soil. Pendimethalin had greater inhibitory effects on gennination than trifluralin.