Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/2001
Publication Date: N/A
Technical Abstract: Sorption and degradation of certain herbicides can be affected by soil properties such as OC, clay content and pH. Theses soil properties can vary spatially across the landscape at the field scale to the extent that it could affect the field dissipation of herbicides. The implications of field dissipation rates that are non-constant in space as well as time opens the door to the possibility of site-specific management of organic chemicals based on soil/herbicide relationships. The spatial variability of surface soils has been characterized for a 5.6 ha watershed in Dakota County, MN, to see if the behavior of acetochlor and isoxaflutole are affected by the variation in those soil properties. The spatial distribution of OC, clay and pH has been described and displayed on a digital elevation model created for the site. The watershed, which has been cultivated in corn, had acetochlor applied at a rate of 2.25 pints per acre eand isoxaflutole applied to the central 2.5 acres of each terrace at a rat of 2.25 ounces per acre to control weeds. At various times after application, the concentrations of acetochlor and isoxaflutole were determined in surface soils as well as at different depths. The spatial-temporal distribution of acetochlor residues across the landscape surface will be discussed.