| Abstract: | The new herbicide propoxycarbazone (sodium methyl 2-(4,5-dihydro-4-methyl-5-oxo-3-propoxy-1H-1,2,4-triazole-1-yl)carbonyl]amino]sulfonyl]benzoate, 1 ) has been measured in the soil of winter wheat crops. In the soil extract, propoxycarbazone was separated from its potential soil metabolites by repeated TLC. Propoxycarbazone was methylated with diazomethane. In the GC and GC-MS apparatus, the N -methylpropoxycarbazone 2 (methyl 2-(4,5-dihydro-4-methyl-5-oxo-3-propoxy-1H-1,2,4-triazole-1-yl)carbonyl]methylamino]sulfonyl]benzoate) generated N -methylsaccharin 4 (1-dioxy-2- N -methyl-3-keto-1,2-benzisothiazol) which was measured. Propoxycarbazone has been applied in the spring at the rate of 70 g ha m 1 post-emergence on winter wheat crops grown in several sites different as to their soil texture and composition. In the 0-10 cm surface soil layer of the winter wheat crops grown on sandy loam (Melle) or on clay loam (Zevekote) soils, the half-life of propoxycarbazone was 54 days. In the winter wheat crop grown on loam soil (Cortil-Noirmont), the propoxycarbazone soil half-life was 31 days. The difference between the propoxycarbazone soil half-lives at the different sites was related to the organic fertilizer treatments applied in the past. After the winter wheat harvest at the end of August, the concentration of propoxycarbazone in soil was very low at Cortil-Noirmont; at the end of September, propoxycarbazone was no more detected. At Melle and Zevekote, the concentration of propoxycarbazone in soil was very low in September, and disappeared completely at the end of October. Since the treatment and until the end of October, propoxycarbazone was not detected in the 10-15 and 15-20 cm surface soil layers of the three trials. |
