The effects of Trifluralin 600 CE on microbial activity measured by CO2 evolution were studied in a Red Yellow Podzolic soil (São Pedro [soil mapping unit] and a Dark Red Latosol (Cruz Alta [soil mapping unit]. The experiment was conducted during 140 days. Treatments with two and four liters of Trifluralin per hectar, in saturated soil and soil with at equivalent to of field capacity. The CO2 evoluted was measured each seven days. After CO2 evolution a biossay using Sorghum bicolor L. Moench was performed to test herbicide persistance. The herbicide did not affect microbial activity. Abnormal seedlings were detected in soil with moisture at 80% of field capacity but none for saturated soil. The abnormal seedling usually indicates persistence of Trifluralin when it is applyed in unsaturated soil conditions.
trifluralin; microbial activity; CO2 evolution
