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Various studies have been conducted into redox potential (Eh), redox indicators and the measured soil water contents in soil (Franzmeier et al., 1983; Schwertmann & Fanning, 1976; Veneman et al., 1976). Although a measure of success has come from these studies, there are still vast knowledge gaps within this field. The degree of water saturation where reduction in the soil is initiated cannot be determined from literature, although it was approximated that 70% of water saturation (S0.7) was sufficient to initiate reduction (Van Huyssteen et al., 2005). This value will vary for different soil temperatures, varying bulk densities as well as soils with different organic matter contents. This study aimed to determine if it was possible to identify a degree of water saturation at which reduction is initiated for a soil in a closed system. It also aimed to determine the effect of bulk density on reduction. Reduction was defined by a decrease in pe (Eh) of a soil and an increase in the soluble Fe2+ concentration. There were three key aims to the study: to establish the relationship between the degree of water saturation (s) and the onset of reduction; to establish the relationship between the degree of water saturation (s) and the duration of reduction and to establish the effect of bulk density on the above-mentioned processes. A yellow brown apedal B horizon from an Avalon soil form (profile 234) in the Weatherley catchment was used in this study. A soil core experiment was carried out to determine the effect of degree and duration of water saturation on Eh, pH, Fe2+, Mn2+, Ca2+, Mg2+, K+, and Na+. Soil cores were packed to a bulk density of 1.6 Mg m-3 and individually saturated to S0.6 (60% of the pores saturated with water), S0.7 (70% of the pores saturated with water), S0.8 (80% of the pores saturated with water), and S0.9 (90% of the pores saturated with water). Measurements were done in triplicate. The cores were sealed with a double layer of plastic wrap and stored