Role of microbial iron reduction in paddy soil

Abstract

The contribution of iron reduction to total degradation of organic matter was studied in slurry experiments of rice soil. Quantification of the different anaerobic processes showed that methanogenesis accounted for 73% and iron reduction for 24%. The organic carbon content of the soil strongly affected the contribution of iron reduction versus methanogenesis. In paddy soil of a lower organic content the contribution of iron reduction to total carbon oxidation increased to 42% and methanogenesis decreased to 51%. Addition of increasing amounts of ferrihydrite to soil slurries increased the contribution of iron reduction gradually up to 87% and inhibited methanogenesis.