The determination of the bulk chemical composition of sulphide-containing soils and badland soils causes difficulties by X-ray fluorescence (XRF) analysis: the content of sulphur is underestimated. The inability to determine the main element, oxygen, is the reason for errors in the XRF bulk chemical analysis of the badland soil. A procedure is proposed for the adjustment of oxygen content in the solid phase of the badland soils using Mössbauer spectrometry data on the content of Fe minerals. The contents of total iron, sulphur, and oxygen in the soils can be corrected in the case of simple iron mineralogy. After correction, the total content of sulphur measured by XRF significantly increases and that of oxygen decreases. The clarified oxygen content of the solid phase of badlands soil can be used to characterize the degree of their degradation.