Effect of redox potential on manganese transformation in waterlogged soil.

Abstract

MANGANESE reduction from insoluble oxidized forms to slightly soluble reduced forms occurs readily when an aerated soil is waterlogged. Together with the disappearance of oxygen and nitrate, an increase in the manganous ion (Mn++) in the soil solution and on the cation exchange complex is one of the first measurable effects of reducing conditions caused by waterlogging. Although reduction and solution of manganese compounds in waterlogged soils are well known, little information is available about the distribution of various forms of manganese in the soil as reduction processes take place. Experimental data are especially lacking on the intensity of reduction required for conversion of oxidized manganese compounds to reduced forms in waterlogged soils. This report deals with the distribution of the various forms of manganese in waterlogged soils and the effects of the oxidation-reduction or redox potential on these transformations.