Laboratório de Ecotecnologia e Limnologia, Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil.
Front Microbiol. 2013 Mar 15;4:56. doi: 10.3389/fmicb.2013.00056. eCollection 2013.
Temporary wetlands are short-term alternative ecosystems formed by flooding for irrigation of areas used for rice farming. The goal of this study is to describe the development cycle of rice fields as temporary wetlands in southern Brazil, evaluating how this process affect the gas production (CH4 and CO2) in soil with difference % carbon and organic matter content. Two areas adjacent to Lake Mangueira in southern Brazil were used during a rice-farming cycle. One area had soil containing 1.1% carbon and 2.4% organic matter, and the second area had soil with 2.4% carbon and 4.4% organic matter. The mean rates of gas production were 0.04 ± 0.02 mg CH4 m(-2) d(-1) and 1.18 ± 0.30 mg CO2 m(-2) d(-1) in the soil area with the lower carbon content, and 0.02 ± 0.03 mg CH4 m(-2) d(-1) and 1.38 ± 0.41 mg CO2 m(-2) d(-1) in the soil area with higher carbon content. Our results showed that mean rates of CO2 production were higher than those of CH4 in both areas. No statistically significant difference was observed for production of CH4 considering different periods and sites. For carbon dioxide (CO2), however, a Two-Way ANOVA showed statistically significant difference (p = 0.05) considering sampling time, but no difference between areas. The results obtained suggest that the carbon and organic matter contents in the soil of irrigated rice cultivation areas may have been used in different ways by soil microorganisms, leading to variations in CH4 and CO2 production.
临时湿地是由灌溉稻田形成的短期替代生态系统。本研究的目的是描述巴西南部稻田作为临时湿地的发展周期，评估这一过程如何影响具有不同碳和有机质含量的土壤中的气体产生（CH4 和 CO2）。本研究在巴西南部的 Mangueira 湖附近的两个地区进行了水稻种植周期。一个地区的土壤含碳量为 1.1%，有机物质含量为 2.4%，第二个地区的土壤含碳量为 2.4%，有机物质含量为 4.4%。含碳量较低的土壤中气体产生的平均速率为 0.04 ± 0.02 mg CH4 m(-2) d(-1)和 1.18 ± 0.30 mg CO2 m(-2) d(-1)，而含碳量较高的土壤中气体产生的平均速率为 0.02 ± 0.03 mg CH4 m(-2) d(-1)和 1.38 ± 0.41 mg CO2 m(-2) d(-1)。我们的结果表明，两个地区的 CO2 产生的平均速率均高于 CH4。考虑不同时期和地点，CH4 的产生没有表现出统计学上的显著差异。然而，对于二氧化碳（CO2），双因素方差分析显示，采样时间存在统计学上的显著差异（p = 0.05），但地区之间没有差异。研究结果表明，灌溉水稻种植区土壤中的碳和有机质含量可能被土壤微生物以不同的方式利用，导致 CH4 和 CO2 产生的变化。
