Degradation of flurtamone in a Greenville sandy clay loam, a Cecil loam, and a Dothan loamy sand with 0, 1, or 2 yr of previous flurtamone field use was evaluated under controlled conditions. Soil sterilization by autoclaving significantly reduced flurtamone dissipation rate in all soils. Enhanced degradation of flurtamone was observed in a Greenville sandy clay loam after 1 yr of previous flurtamone field use and in a Cecil loam after 2 yr of previous flurtamone field use. No enhancement of flurtamone degradation was observed in a Dothan loamy sand. Flurtamone degradation kinetics in these studies was described as a first-order process. Microbial populations in each soil showed no major changes in total bacterial numbers due to preexposure to flurtamone in the field.

Flurtamone and atrazine adsorption to soil was examined using a batch equilibrium method. Flurtamone mobility in packed soil columns under saturated flow conditions was also evaluated. Adsorption was greater for flurtamone than atrazine in the three soils, and the order of adsorption to soil for both herbicides was Greenville sandy clay loam > Cecil loam > Dothan loamy sand. Greater adsorption of each herbicide corresponded to soils with greater organic matter and clay content. The 14C–flurtamone movement under saturated flow conditions in 28–cm soil–packed columns was limited to 16 cm, with no flurtamone leaching from any soil column after the addition of two pore volumes of water. Seventy–five percent of the applied 14C–flurtamone remained in the 0– to 4–cm soil depth in the Greenville sandy clay loam, with less than 5 percent moving to a depth > 4 cm. Flurtamone movement was greater in the Cecil loam and the Dothan loamy sand, with movement in each soil to a depth of 16 and 12 cm, respectively.

The dissipation of flurtamone was determined in three Georgia soils in 1987 to 1989. Flurtamone dissipation in soil was initially rapid but gradually slowed throughout the sampling interval. Dissipation was not affected by rate (0.8 or 1.7 kg ai ha-1) or application method (PPI or PRE). Dissipation rates were slightly more rapid in the Greenville and Dothan soils than in the Cecil soil, with calculated initial half-lives for each respective soil being 6 to 7, 8 to 10, and 9 to 23 days. There was no effect of previous flurtamone exposure on the dissipation rate in soil at any location.