“…In submerged rice soil, many kinds of organic materials are present, and Fe(III) oxides become soluble by combining with some of these organic materials in soil (Esaki et al 1993). Almost all the Fe(III) reduction is carried out by Fe(III)-reducing bacteria in soil (Takai and Kamura 1966), and the bacteria utilize Fe(III) compounds in the soil solution (Wahid and Kamalan 1993). The electron donor ability of the soil was greater than that of Fe(D) presumably because the solubility of some organic materials in soil was bigger than that of Fe(D).…”