Submitted to: American Chemical Society Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 7/15/2006
Publication Date: 9/10/2006
Citation: Caberera, A., Cox, L., Koskinen, W.C. 2006. Soil organic amendment as affecting herbicide fate. American Chemical Society Abstracts. p. 99. Interpretive Summary:
Technical Abstract: The addition of organic amendments or organic wastes to soils have been shown to affect the fate of soil applied herbicides, although it is an issue very seldom considered when making the decision of fertilizing soil or disposing organic wastes. The addition of organic wastes to soils is viewed as very beneficial in retarding pesticide movement through agricultural soils, due to the subsequent increase in soil organic matter. This increase in organic matter, in general, increases pesticide sorption. Sorption-desorption interactions of herbicides with soil components determine the availability of the chemical in soil for microbial degradation and leaching. Herbicide that is sorbed to soil particles is not instantaneously bioavailable, it must first desorb from the soil into solution. The aim of this work was to investigate on the effect of soil addition of an organic residue from olive oil production process on sorption-desorption, dissipation and leaching of the soil applied herbicides diuron and terbuthylazine, which are the most frequently used herbicides in Spanish olive groves. Sorption studies revealed an increase in sorption of both herbicides upon amendment with the organic residue. Sorption not only increased but sorption irreversibility also increased with amendment. When herbicides diuron and terbuthylazine were coapplied, sorption reversibility increased. Diuron persistence increased upon amendment whereas half lives for terbuthylazine decreased. Leaching of the herbicides in soil columns was reduced in both cases.