Suppression of methane emission from rice paddies by ferric iron fertilization

Rice microcosms incubated in the greenhouse showed that methane emission was reduced after fertilization of the soil with ferric iron oxide–ferrihydrite. The total methane emission during the vegetation period of rice was reduced by 43% and 84%, with the addition of 15 and 30 g of ferrihydrite per kg of soil, respectively. Growth of the rice plants was reduced during the first few weeks in the ferrihydrite fertilized soil but was unchanged after 14 weeks. The number of rice seeds produced per plant was identical after the lower iron fertilization and was 82% of the control after the higher iron fertilization. The presence of ferric iron suppressed methanogenesis and methane emission in rice microcosms.