The degradation of metamitron, a sugar beet herbicide, in soil was studied
in laboratory conditions and in field lysimeters under different irrigation
water volumes. An identification of degradation compounds was also attempt
ed. Laboratory degradation followed a first-order kinetics with a half-life
of 18.2 days while lysimeter dissipation was consistently rapid with a hal
f-life ranging from 4.4 to 8.0 days under the different irrigation conditio
ns. A degradation compound appeared as early as the first few days in both
laboratory and lysimeter samples and was identified as 4-(dimethylimino)-3-
methyl-6-phenyl-1,2,4-triazin-5(4H)-one by GC/MS and NMR spectra. ((C) Inra
/Elsevier, Paris.).