Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history

Authors: Krutz, Larry; Shaner, Dale; Zablotowicz, Robert; Weaver, Mark; Reddy, Krishna

Submitted to: Agricultural Research Service Station Bulletin
Publication Type: Government Publication
Publication Acceptance Date: 11/25/2009
Publication Date: 1/15/2010
Citation: Krutz, L.J., Shaner, D.L., Zablotowicz, R.M., Weaver, M.A., and Reddy, K.N. 2010. Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history. Agricultural Research Service Station Bulletin, Crop Production Systems Research Unit Fact Sheet. 2010-01.

Interpretive Summary:

Technical Abstract: Soil bacteria on all continents except Antartica have developed the ability to rapidly degrade the herbicide atrazine, a phenomenon referred to as enhanced degradation. The agronomic significance of enhanced degradation is the potential for reduced residual weed control with atrazine in Corn, Sorghum, and Sugarcane production systems. Reduced residual weed control with atrazine has only been confirmed under Mississippi Delta corn production systems, but researchers working with corn and other crops in Colorado, Hawaii, Louisiana, Mississippi, Tennessee, and Texas have attributed reduced residual weed control with atrazine to enhanced degradation and not s-triazine resistant weed biotypes, improper application techniques, or lack of activation. These observations have lead USDA-ARS scientists to 1) delineate the physical and chemical range of all soils where enhanced degradation presently occurs; 2) determine the impact of cultural practices on the occurrence of enhanced degradation, and 3) develop a model that allows producers and consultants to determine atrazine persistence in production fields based on soil pH and herbicide use history.