|Bresnahan, G - NORTH DAKOTA STATE UNIV|
|Dexter, A - NORTH DAKOTA STATE UNIV|
Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 2000
Publication Date: N/A
Technical Abstract: Availability of imidazolinone herbicides is affected by sorption processes, which in turn can be affected by pH and incubation time (aging). The effect of pH on sorption of imazethapyr and imazamox in aged soils was determined. Both herbicides degraded during a 6-mo laboratory incubation of a Ves loam soil spiked with 14C-labeled herbicide, but soil pH between 5.4 and 7.7 did dnot significantly affect the amounts of either herbicide remaining at any sampling time. Sorption increased for both herbicides as a function of incubation time. The increase in sorption with time, a process that is reversible, appears to be a function of the rate of formation of the imidazolinone cation, which is sorbed by cation exchange on the soil surface. When the aged soil pH was raised with lime, sorption decreased to that predicted from the pH of freshly spiked soil.