DISSIPATION OF IMAZAQUIN IN SOUTHERN SOILS

Soil-applied imazaquin was characterized by rapid initial dissipation followed by a slower second phase breakdown following field application in soybean. Relative rates of imazaquin dissipation from fastest to slowest in 1988 were: Captina silt loam = Marietta loam > Dothan (NC) loamy sand = Dothan (FL) sandy loam = Port loam = Pullman silty day loam = Appling sandy loam = Maury silt loam = Statler loam. No differences in dissipation rate among sites were not detected in 1989. In 1990, relative rates of imazaquin dissipation from fastest to slowest were: Port loam > Dothan (FL) loamy sand = Dothan (NC) sandy loam = Appling sandy loam = Maury silt loam = Pullman silty clay loam. A negative correlation between soil temperature and the imazaquin DT50 was observed. Soil pH, organic matter content, or clay content did not influence the dissipation pattern of imazaquin in these studies.