Acid concentration-dependent multivalent cation

When phenolic acids enter the soil environment they are reversibly and irreversibly sorbed to soil particles, polymerized, oxidized, reduced, leached, utilized by microbes, and taken up by roots. Rates for these various processes are highly variable and depend on soil type, biotic and physicochemical soil environmenL types and mixtures of phenohc acids in or added to soils, and time, among others. To eliminate the effects of soil microbes, soils may be autoclaved. Concentrations of individual available phenolic acids in soils at a given point in time may be estimated by extracting soils with appropriate extractants and HPLC analysis. Based on our soils, we recommend water for estimating soil solution concentrations and neutral EDTA for soil solution and reversibly sorbed phenolic acid concentrations. However, the effectiveness of neutral EDTA in recovering available phenolic acids in all other soils should not be assumed. Reversibly sorbed phenolic acids increased or decreased as soil solution concentrations and multivalent cations increased or decreased, respectively. 

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