Soil herbicides residual life

Simazine and propazine are the two triazine herbicides with the longest duration of action In a dose of 10-15 kg/ha the residual life is 2-3 years. Under dry climatic conditions their weed-control activity is unsatisfactory because with their poor water-solubility they are not leached by the low soil moisture to the roots of the weeds. 

Chlorsulfuron is a residual soil herbicide. Its half-life in the soil is 1-2 months. 

Soil. Bartha and Pramer (1967) reported that DCPA was degraded by soil microorganisms via cleavage of the herbicide molecule into propionic acid and 3,4-dichloroaniline. The acid was mineralized to carbon dioxide and water and two molecules of 3,4-dichlo-roaniline were condensed to form 3,3 4,4 -tetrachloro-azobenzene. Metabolites identified in soil and turfgrass thatch are monomethyl tetrachloroterephthalate and 2,3,5,6-tetrachlo-roterephthalic acid (Hartley and Kidd, 1987 Krause and Niemczyk, 1990). Residual activity in soil and the half-life in soil were reported to be approximately 3 months (Hartley and Kidd, 1987 Worthing and Hance, 1991). 

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