The Oxidation‐Reduction Potential of Alkaline Calcareous Soils in Relation to Puddling and Organic Matter Decomposition¹

A laboratory evaluation of the Sewage Osmosis concept

“…The redox potential (Eh) is a function of the pH since the hydrogen ion activity appears in the term [Red] of the Nernst equation. Buehner and his coworkers (Buehner et al, 1939) summarize the values obtained for the constant of proportionality relating Eh to pH in soil as found by various investigators. This illustrates the wide empirical deviation from the theoretical value of -0.059 as determined by the evaluation of the con stants of the Nernst equation (Michaelis, 1930;Hewitt, 1936).…”

“…Soil is a complex medium and therefore tends to have somewhat vari able chemical and physical properties. The change in a soil's redox potential was studied by a number of workers in the earlier part of this century (Bradfield et al, 1934;Brown, 1934;Buehner et al, 1939;Gillesple, 1920;Heintze, 1935;Quispel, 1947;Volk, 1939;Pearsall, 1938;Stephenson et al. 1938;and Willis, 1932) in order to characterize the soil in a simple, reproducible way.…”

A laboratory evaluation of the Sewage Osmosis concept

“…The change in a soil's redox potential was studied by a number of workers in the earlier part of this century (Bradfield et al, 1934;Brown, 1934;Buehner et al, 1939;Gillesple, 1920;Heintze, 1935;Quispel, 1947;Volk, 1939;Pearsall, 1938;Stephenson et al. 1938;and Willis, 1932) in order to characterize the soil in a simple, reproducible way.…”

“…Quispel suggests that platinum black electrodes, which catalyze oxygen reactions preventing the formation of platinum oxides, be used to obtain reproducible results that agree more closely with theoretical values. Buehner et al (1939) emphasized the importance of welding or soldering the platinxim electrode to its copper conductor, since the mercury contact used by earlier workers was found to produce erratic potentials attributed to the poisoning effect of the mercury. Armstrong (1967) and Poel (1960) both developed similar elec trodes for in-field use; these essentially consisted of an externally insulated steel conductor to the end of which was soldered a bright plat inum wire.…”