Abstract:【Objective】 As iron reduction and oxidation processes in soil are closely related to bio-availability of heavy metals, degradation of organic pollutants and emission of carbon-containing greenhouse gases, they have aroused increasing concern among scholars. Temperature is a factor that may affect iron redox in soil by influencing activity of ferric reduction and ferrous oxidation bacteria, and bio-availability of substrates. Temperature sensitivity of heterotrophic respiration, which is driven by iron redox processes, has been intensively investigated, but little has been done on temperature sensitivity of iron redox processes in wetland soils. 【Method】So in this paper, soil samples were collected from paddy fields or wetlands in Yuanyang County of Xinxiang City, Henan Province, a major rice production area in the middle and lower reaches of the Yellow River for analysis of temperature sensitivity of iron redox processes in the soil through temperature-controlled anaerobic incubation. Samples of the paddy or wetland soil were prepared into slurry and then incubated anaerobically in darkness or under illumination at a preset temperature, and ferrous in the slurry was analyzed periodically to monitor temperature sensitivity of iron oxides reduction and ferrous oxidation in darkness and under illumination. Air in the headspace of the vials after 3 days of incubation was analyzed for O2 using an optical fiber oxygen detector (PreSens Microx 4, Germany Regensburg), and for CO2 using a gas chromatographer (GC7900, China Shanghai Tianmei) equipped with a TCD detector. Water soluble organic and inorganic carbon in the slurry was measured with a TOC analyzer (TOC-VCPH Japan Shimadzu) after the incubation. 【Results】Results show that temperature varying in the range of 16 oC ~ 31 oC did not have much effect on ferric reduction capacity in the soil samples, but it did increase the maximum rate and rate constant of iron reduction significantly, and advance the peaking time, when increasing from 16 oC to 40 oC. O2 was found accumulating in the headspace after 3 days of anaerobic incubation in light, and the accumulation increased with increasing incubation temperature. Water soluble inorganic carbon and CO2 increased dramatically with rising temperature in slurries under incubation in darkness, but no detectable CO2 and only little WSIC was found in the vial under illuminated incubation. 【Conclusion】 Temperature-sensitivity coefficient of iron reduction increased from 1.18 to 3.05 with rising temperature, but decreased under illumination by 39.0% on average. Temperature insensitivity of ferrous oxidation was observed during incubation in light. Quality and quantity of iron oxides and illumination conditions are supposed to be potential key factors affecting mineralization of organic carbon in wetland soils. All the findings in this paper could be of great significance to further efforts to understand biogeochemical cycle of iron in soil and its relationship with soil respiration.