title: Translocation and degradation of pyrazosulfuron-ethyl in rice soil.
abstract: BACKGROUND
  Pyrazosulfuron-ethyl {ethyl 5-[(4,6-dimethoxypyrimidin-2-ylcarbamoyl)-sulfamoyl]-1-methylpyrazole-4-carboxylate} is a new rice herbicide belonging to the sulfonylurea group. This study reports the translocation of (14)C-pyrazosulfuron-ethyl to rice plants and its degradation in rice-planted and unplanted soil.
  
  
  RESULTS
  Pyrazosulfuron-ethyl did not show any appreciable translocation to rice shoots, as (14)C-activity translocated to the aerial portion never exceeded 1% of the initially applied (14)C-activity over a 25 day period. Results suggested that the dissipation of pyrazosulfuron-ethyl from soils followed first-order kinetics with a half-life of 5.5 and 6.9 days in rice-planted and unplanted soils respectively. HPLC analysis of the organic extract of soil samples showed the formation of three metabolites, namely ethyl 5-(aminosulfonyl)-1-methyl-1-H-pyrazole-4-carboxylate, 5-[({[(4,6-dimethoxy-2 pyrimidinyl)-amino]-carbonyl} amino)-sulfonyl]-1-methyl-1H-pyrazole-4-carboxylic acid and 2-amino-4,6-dimethoxy pyrimidine, in both rice-planted and unplanted soils.
  
  
  CONCLUSIONS
  The study indicates that pyrazosulfuron-ethyl was a short-lived compound in the soil and was degraded relatively faster in rice-planted soil than in unplanted soil. The herbicide did not show any appreciable translocation to rice plants.
authors.affiliation: Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi, India. drneerasingh@yahoo.com
authors.forename: Neera
authors.initials: N
authors.lastname: Singh
authors.forename: Shashi B
authors.initials: SB
authors.lastname: Singh
mesh_terms: D001673:Biodegradation, Environmental; D006207:Half-Life; D006540:Herbicides / Q000032:analysis / Q000378:metabolism*; D007194:India; D012275:Oryza / Q000737:chemistry / Q000378:metabolism*; D011720:Pyrazoles / Q000032:analysis / Q000378:metabolism*; D011743:Pyrimidines / Q000032:analysis / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D006540:Herbicides; D011720:Pyrazoles; D011743:Pyrimidines; D012989:Soil Pollutants; C433343:ethyl 5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate