Mineralization of sulphur in sulphoquinovose by forest soils

Surface soils from four watersheds located in the Coweeta Basin near Franklin, North Carolina were assayed for their capacity to mineralize sulphur in 6-sulphoquinovose. All soils rapidly converted S in this component of the plant sulpholipid to inorganic sulphate, a soluble (salt extractable) ester sulphate and an insoluble ester sulphate. Sulphur in this latter fraction was released by acidhydrolysis of soil residues at 121°C. Although maximum concentrations of S in each fraction varied with duration of incubation, rates of conversion of S into all fractions were highest during the first hour. Mineralization rates based upon sulphate release and total S released from sulphoquinovose are reported.