The aims of this paper were: to state if the soluble substances contained in organic or organic-mineral soils can reduce in the same range of potentials as oxygen, falsifying (revaluing) the results of the potential oxygen flux density derived using amperometric and/or voltamperometric methods; to evaluate a correction which would enable one to eliminate this systematic error. The conclusions which are stated in the paper are: the voltamperometric method of oxygen flux density (OFD) measurements in organic soils enables one to obtain more reproducible results than the amperometric (ODR) method; as far as the values of the current obtained with the two methods can be interpreted in terms of potential oxygen flux density in soil, the obtained results are expressed by the relation: ODR (result from amperometric method) ť 2 OFD (result from voltammetric method); the contribution of the background current in the value of the potential oxygen flux density, determined with the use of the voltamperometric method is smaller than that obtained with the amperometric method; the corrections, taking into account the background current in organic and mineralorganic soils which should be subtracted from derived values of the potential oxygen flux density in the soil are: 10.8 for ODR and 5.5 mg m�2 s�1 for OFD; the results obtained both with amperometric and voltamperometric methods should be treated rather as an indicator, indicating the oxidation status of the soil, than as a real meter of the amount of oxygen available for the plant roots.