It has been recently reported that silicon (Si) increases methane (CH₄) emission from peats through mobilizing phosphorus and organic carbon bound to iron minerals and stimulating microbial activities. However, it is unknown whether this effect of Si applies in other environments, such as warm temperate forest soils that function primarily as a CH₄ sink but occasionally as a CH₄ source. We tested our hypothesis that CH₄ emission should increase with Si availability in warm temperate forest soils under anaerobic conditions, by incubating four soil samples collected from a variety of topographic positions in the Kiryu Experimental Watershed, in Shiga, Japan. The soil characteristics including soil pH and total phosphorus and iron contents varied among the soils. Much greater CH₄ emission was observed in the soils from the riparian wetland areas than in those from the upland areas. The onset of methanogenesis was not accelerated by Si addition during the incubation. At the end of the incubation, the Si addition did not increase total CH₄ production from the soils. A lack of the Si effects would be due to low quantities of phosphorus retained by iron minerals in the entire area of this watershed and high abundance of more potent electron acceptors in the upland. Overall, our results suggest that increasing Si availability exerts little influence on CH₄ emissions from warm temperate forest soils under the used experimental conditions in this watershed.

最近有报道称，硅 (Si)通过调动与铁矿物结合的磷和有机碳并刺激微生物活动，增加了泥炭中的甲烷 (CH ₄ ) 排放。然而，Si 的这种影响是否适用于其他环境尚不清楚，例如主要作为 CH ₄汇但偶尔作为 CH ₄源的暖温带森林土壤。我们检验了我们的假设，即 CH ₄通过培养从日本滋贺市桐生实验流域的各种地形位置收集的四个土壤样品，在厌氧条件下，随着暖温带森林土壤中硅的可用性，排放量应增加。土壤特性，包括土壤 pH 值和总磷和铁含量，因土壤而异。在河岸湿地地区的土壤中观察到的CH ₄排放量远大于高地地区的土壤。在孵化过程中加入硅并没有加速产甲烷的开始。在孵化结束时，Si 的添加没有增加总 CH ₄从土壤中生产。缺乏 Si 效应将是由于该流域整个区域中铁矿物保留的磷含量低，而高地中更有效的电子受体的丰度高。总体而言，我们的结果表明，在该流域使用的实验条件下，增加 Si 可用性对暖温带森林土壤的CH ₄排放几乎没有影响。