Submitted to: Intnl Conference On Geospatial Information In Agriculture And Forestry
Publication Type: Abstract Only
Publication Acceptance Date: 11/6/2001
Publication Date: N/A
Technical Abstract: Sorption and degradation of herbicides can be affected by soil properties such as OC, %clay and pH. These soil properties can vary spatially across the landscape to the extent that field dissipation rates of some herbicides could vary as well. The implication of field dissipation rates that are non-constant in space as well as time could lead to implementation of site-specific management in the application of organic chemicals within a field based on soil/herbicide relationships. A digital elevation model has been created for a 6 ha watershed in Rosemount, MN cultivated in corn. The spatial distribution of OC, %clay and pH has been determined from an approximate 25 m grid sampling scheme. OC ranges from 1.18 to 4.15, pH from 5.52 to 7.56 and %clay from 12.30 to 27.0. Acetochlor was applied at the recommended uniform rate of 2.2 kg ha-1 to evaluate the affect of surface soil properties on herbicide residues across the watershed in space eas well as over time. GIS and geostatistical methods were used to determine spatial-temporal patterns in field dissipation rates and their relationship to surface soil properties. Initial analyses indicate no linear correlation between pH, OC or %clay with acetochlor residues over time and that there is no apparent spatial autocorrelation of acetochlor residues across the field.