Evaluation of imazaquin and trifluralin soil residual activity through corn bioassays

Abstract

Soil samples containing imazaquin and trifluralin were used to conduct corn bioassays in a greenhouse. The visual symptoms of corn phytotoxicity cultivated with trifluralin decreased faster than in soils with imazaquin application. Imazaquin residues caused the biomass reduction of the corn aerial part in all doses up to 60 days after the application (DAA), but such effect was evident up to 90 DAA for doses higher than 180g/ha. For corn roots, however, the effect was longer and only after 120 DAA no more weight reduction was detected. Trifluralin residual effect on corn plants was more evident in the roots than in the shoot, and the root growth reduction was observable up to 150 DAA. Imazaquin phytotoxicity was observed in 10-20 cm-deep soil samples, thus suggesting a higher potential for soil leaching.