Atrazine Degradation in Two Soil Profiles

Two – chloro – 4- ethylamino – 6 – isopropylamino – s – triazine (atrazine) is a herbicide much used throughout the U.S. for control of weeds in corn, sorghum, and nursery crops as well as a temporary soil sterilant. Carry-over of atrazine in soil has caused injury to succeeding crops and until several years ago no residue of atrazine in the topsoil was generally assumed to mean degradation to non-phytotoxic products. However, Burnside et al. showed that leaching can be a significant mode of atrazine dissipation from the surface soil. The question which now arises is what happens to atrazine in the subsoil where factors affecting degradation would differ from those in the topsoil. This research reports studies of atrazine degradation in two soil profiles and the effects of moisture content, microorganism populations, temperature, and adsorption on atrazine degradation. The relative rates and factors influencing the rate of atrazine degradation in two soil profiles were studied in laboratory and field experiments. Advisor: Terry L. Lav