Norflurazon adsorption and dissipation under field and laboratory cond
itions, and distribution within the soil profile were determined in th
ree soils representative of cotton-growing regions of the southeastern
U.S. Norflurazon adsorption was greater in soil from 0 to 8 cm in a L
exington silt loam (Tennessee) and a Beulah silt loam (Mississippi) th
an in a Dothan loamy sand (Georgia). Adsorption was directly related t
o organic matter. Norflurazon degradation under controlled conditions
in soil from 0 to 8 cm from each state was not different among locatio
ns, with, half-lives ranging from 63 to 167 d. Degradation at 30 C in
soil from the 30- to 45- and 60- to 90-cm depths was nor different amo
ng locations, and was slower at the 60- to 30-cm depth than in surface
soil. Norflurazon dissipation was more rapid under field conditions t
han under laboratory conditions, with half-lives ranging from 7 to 79
d in the 0- to 8-cm soil horizon. Dry field conditions slowed norflura
zon dissipation. Norflurazon was not detected below 15 cm in the profi
le in any soil, and concentrations in the 8- to 15-cm soil zone were <
36 ppbw 112 d after treatment.