Effect of soil characteristics on sequential reduction and methane production in sixteen rice paddy soils from China, the Philippines, and Italy
Effect of soil characteristics on sequential reduction and methane production in sixteen rice paddy soils from China, the Philippines, and Italy
复制标题
DOI：
10.1007/bf00992910
复制
发表时间：
1999-12
期刊：
影响因子：
4
通讯作者：
H. Yao;R. Conrad;R. Wassmann;H. Neue
中科院分区：
文献类型：
--
作者：
H. Yao;R. Conrad;R. Wassmann;H. Neue
The potentials for sequential reduction of inorganic electron acceptors and production of methane have been examined in sixteen rice soils obtained from China, the Philippines, and Italy. Methane, CO2, Fe(II), NO3−, SO42−, pH, Eh, H2and acetate were monitored during anaerobic incubation at 30 °C for 120 days. Based on the accumulation patterns of CO2and CH4, the reduction process was divided into three distinct phases: (1) an initial reduction phase during which most of the inorganic electron acceptors were depleted and CO2production was at its maximum, (2) a methanogenic phase during which CH4production was initiated and reached its highest rate, and (3) a steady state phase with constant production rates of CH4. and CO2. The reduction phases lasted for 19 to 75 days with maximum CO2production of 2.3 to 10.9μmol d−1g−1dry soil. Methane production started after 2 to 87 days and became constant after about 38–68 days (one soil >120 days). The maximum CH4production rates ranged between 0.01 and 3.08μmol d−1g−1. During steady state the constant CH4and CO2production rates varied from 0.07 to 0.30μmol d−1g−1and 0.02 and 0.28μmol d−1g−1, respectively. Within the 120 d of anaerobic incubation only 6–17% of the total soil organic carbon was released into the gas phase. The gaseous carbon released consisted of 61–100% CO2, <0.1–35% CH4, and <5% nonmethane hydrocarbons. Associated with the reduction of available Fe(III) most of the CO2was produced during the reduction phase. The electron transfer was balanced between total CO2produced and both CH4formed and Fe(III), sulfate and nitrate reduced. Maximum CH4production rate (r=0.891) and total CH4produced (r=0.775) correlated best with the ratio of soil nitrogen to electron acceptors. Total nitrogen content was a better indicator for “available” organic substrates than the total organic carbon content. The redox potential was not a good predictor of potential CH4production. These observations indicate that the availability of degradable organic substrates mainly controls the CH4production in the absence of inorganic electron acceptors.
