|Chee Sanford, Joanne|
|Shaffer, Elizabeth - UNIV OF ILLINOIS|
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 24, 2005
Publication Date: February 7, 2005
Citation: Sims, G.K., Chee Sanford, J.C., Cupples, A.M., Shaffer, E.A. 2005. Nutritional limitations for biodegradation of herbicides [abstract]. Weed Science Society of America. 44:74. Technical Abstract: Our previous research showed that microorganisms degrade the atrazine ring primarily as a source of nitrogen rather than carbon or energy, and that ambient N concentrations in agricultural soils may be sufficient to inhibit atrazine degradation in situ. These findings have since been followed up with biodegradation (mineralization) studies using soils from the University of Illinois Morrow plots to examine the impact of N deprivation on microbial utilization of atrazine and cloransulam-methyl (C-M). In addition, studies were performed to assess the impact on exogenous soil N on degradation of differentially labeled C-M (phenyl versus pyrimidine ring label). Long-term N privation resulted in rapid degradation of atrazine and the pyrimidine moiety of the C-M molecule, whereas limited effects were observed on degradation of the C-M phenyl ring. In sandy soils of very low ambient N content, it was shown that mineralization of the C-M phenyl ring is stimulated by exogenous N, whereas degradation of the pyrimidine ring was somewhat inhibited. These findings suggest a potential for nutritional effects on certain herbicides, particularly those with heterocyclic ring systems.