Molecular Structure of Herbicides and their Sorption by Soils

PARTITION between soil and water of organic compounds that do not ionize in the pH range 4–8 is closely correlated with the soil's content of organic matter. Lambert1 and Furmidge amd Osgerby2 have expressed sorption in terms of partition coefficients between soil organic matter and water, neglecting mineral constituents. Some investigators have also reported inverse correlations between water solubility and sorption on soil whereas others have found no relationship2,3. Little is known about the mechanisms of sorption on soil, but apparently only a small fraction of the surface is responsible for the sorption of certain herbicides3. I have attempted to learn more about sorption mechanisms by studying how changes in the chemical structure of related compounds affect sorption. RESP-6045