Degradation of the herbicide benzoylprop‐ethyl in soil

摘要

AbstractThe degradation of 14C benzoyl prop ethyl (SUFFIX,aethylN‐benzoyl‐N‐(3,4‐dichlorophenyl)‐2‐aminopropionate) in four soils has been studied under laboratory conditions.The major degradation product of benzoylprop ethyl at up to 4 months after treatment was its corresponding carboxylic acid (II). On further storage this compound became firmly bound to soil before it underwent a slow debenzoylation process which led to the formation of a number of products includingN‐3,4‐dichlorophenylalanine (IV), benzoic acid, 3,4‐dichloroaniline (DCA), which was mainly present complexed with humic acids, and other polar products. Although these polar products were not identified, they were probably degradation products of DCA, since they were also formed when DCA was added to soil. No 3,3′,4,4′‐tetrachloroazobenzene (TCAB) was detected in any of the soils at limits of detectability ranging from 0.01‐0.001 parts/million.SinceN‐3,4‐dichlorophenylalanine (IV) and 3,4‐dichloroaniline were transient degradation products of benzoylprop ethyl, the metabolism in soil of radiolabelled samples of these compounds was also studied.In these laboratory experiments the persistence of the herbicide increased as the organic matter content of the soil increased and the time for depletion of half of the applied benzoylprop ethyl varied from 1 week in sandy loam and clay loam s