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United States Department of Agriculture

Agricultural Research Service

Title: How Rapidly Does Enhanced Atrazine Degradation Develop

item Shaner, Dale
item Khosla, Raj
item Stromberger, Mary

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2009
Publication Date: 2/12/2010
Citation: Shaner, D.L., Khosla, R., Stromberger, M. 2010. How Rapidly Does Enhanced Atrazine Degradation Develop. Weed Science Society of America Meeting Abstracts. Denver,Colorado Feb 17-11,2010

Interpretive Summary:

Technical Abstract: Enhanced atrazine degradation has been documented in multiple fields in Colorado. A random survey of 70 fields in eastern Colorado showed that approximately 30% had enhanced atrazine degradation. However, the enhanced degradation is not necessarily long term. Twenty-five fields were tested in 2007 and then re-tested in 2009. In most of the fields the rate of atrazine degradation remained the same, but in other fields the rate either increased or decreased, suggesting that the populations of microorganisms responsible for degradation may not be stable. The question was how rapidly enhanced degradation can develop. A study was done to measure the development of enhanced atrazine degradation. Soils tested in March, 2007 prior to atrazine application degraded atrazine in the laboratory slowly with a half life of 23 d. Atrazine was applied to one part of the field in June, 2008 and the soils from treated and untreated plots were assayed in October, 2008. The half life of atrazine in the untreated soil remained at 23 d, whereas the half life of atrazine in the treated soil had fallen to 2.8 d. The soil was retested in May, 2009 and the half lives remained the same as measured in October, 2008. Atrazine at 1.12 kg/ha was applied to the soil showing enhanced atrazine degradation on May 13, 2009 and the dissipation of the herbicide was measured. Over 95% of the atrazine had degraded to by June 25, 2009. These results show that enhanced atrazine degradation can develop rapidly in a soil and result in rapid dissipation of the herbicide in the field.

Last Modified: 07/25/2017
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