THIS communication reports the occurrence of p-hydroxybenzoic, vanillic, p-coumaric and ferulic acids in four different soils of contrasting types (Table 1). Other workers have obtained these compounds by chemical degradation of humic acid1–3, and also from decomposing straw4; but reviews of the chemistry of soil organic matter5–7 indicate that only p-hydroxybenzoic acid has been previously identified in a free state in soils.