|Hansen, Neal - COLORADO STATE UNIVERSITY|
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 12, 2008
Publication Date: February 19, 2009
Citation: Shaner, D.L., Wiles, L., Hansen, N. 2009. Effect of Cropping Pattern and Crop Residue on Herbicide Binding to Soil. Weed Science Society of America Annual Meeting Abstracts. Orlando Florida February 9-12, 2009. Technical Abstract: The binding of herbicides to soil is dependent on many factors, including soil texture, organic matter, and pH. In 2007 we were conducting an experiment to determine the effect of cropping patterns on atrazine efficacy and fate, and found that there was a significant relationship between cropping pattern and the binding of atrazine to soil from the top 7.5 cm. Atrazine bound more tightly to soil from plots where the previous year’s crop was corn compared to soil where the previous year’s crop was wheat. In 2008 these same differences were also observed. Three other herbicides, metribuzin, sulfentrazone and metolachlor, also bound more tightly to soil where the previous crop had been corn compared to wheat. The differences in binding could not be attributed to differences in soil texture, organic matter or pH. Surface crop residue was measured in 2008 and there was no difference in the total mass amongst the crop rotations. However, when the binding of these herbicides to aged crop residue removed from the corn plots and the wheat plots was measured, there were significant differences between the residues. All of the herbicides bound more tightly to corn residue compared to wheat residue. Thus, it appears that the type of crop residue in the soil was a major determinant of herbicide binding. These differences could have an impact on the herbicide efficacy as well as leaching behavior.