The Relationship between Redox Potential and Soil Conditions with Special Reference to Rice Soils: An Overview

Chemical changes during flooding/waterlogging or submerging of soil, particularly rice field ecosystems are very important in determining the suitability of the soil for rice production. Flooding the soil, changes this condition drastically. One of the most important soil physicochemical parameters used to characterise submerged soils is the redox potential (Eh). Redox potential measurements are useful as an index of the oxidation-reduction status of flooded soils. The main electrochemical changes in submerged soils are decreased in redox potential. Redox reactions in the soil are mostly the result of a cycle started by photosynthesis. Changes in Eh as a factor of time after flooding are listed in order: O2, NO3, MnO2, Fe^3+ , SO4^-2 and CH4. A brief explanation for each redox reaction system is also provided.