Stable carbon isotope fractionation, carbon flux partitioning and priming effects in anoxic soils during methanogenic degradation of straw and soil organic matter
Stable carbon isotope fractionation, carbon flux partitioning and priming effects in anoxic soils during methanogenic degradation of straw and soil organic matter
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DOI：
10.1016/j.soilbio.2012.02.030
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发表时间：
2012-06-01
影响因子：
9.7
通讯作者：
Chidthaisong, Amnat
中科院分区：
文献类型：
--
作者：
Conrad, Ralf;Klose, Melanie;Chidthaisong, Amnat
秸秆改良是提高稻田土壤肥力的常见做法，但它也增加了温室气体甲烷的产生。为了量化碳通量分配和启动效应，由于秸秆修正案，我们测量了Δ C-13的甲烷和甲烷前体产生的缺氧泥浆的土壤从意大利，中国和泰国后，秸秆从水稻（C3植物）或玉米植物（C4植物），这有不同的Δ C-13签名。所产生的CH 4、乙酸盐和CO2的Δ C-13值在表示为与所施用的秸秆的Δ C-13值的差时是相似的。这些结果表明，水稻秸秆和玉米秸秆的甲烷分解所涉及的碳13同位素分馏是相似的。然而，在土壤中产生的CH 4没有或秸秆的测量表明，同位素分馏秸秆产甲烷降解过程中小于土壤有机质降解。同位素分馏氢营养甲烷，在甲基氟的存在下，测量秸秆也小于土壤有机质。结果表明，施用水稻秸秆和玉米秸秆后的碳13同位素分析是一种方便的方法，可以定量分析秸秆和土壤有机质产甲烷降解过程中碳通量分配。在我们的实验中，秸秆降解占大部分的CH 4的产生，并造成负启动效应的土壤有机质的甲烷降解。(c)2012爱思唯尔有限公司保留所有权利。
Straw amendment is a common practice for improving the fertility of rice field soils, but it also enhances production of the greenhouse gas methane. To quantify carbon flux partitioning and priming effects due to straw amendment, we measured delta C-13 in CH4 and CH4 precursors produced in anoxic slurries of soil from Italy, China and Thailand after addition of straw from either rice (C3 plant) or maize plants (C4 plant), which have different delta C-13 signatures. The delta C-13 values of the CH4, acetate and CO2 produced were similar when expressed as the difference to the delta C-13 value of the straw applied. These results indicated that the C-13-isotopic fractionation involved in methanogenic decomposition was similar for rice straw and maize straw. However, measurement of CH4 produced in soil without or with straw showed that isotopic fractionation during methanogenic degradation of straw was smaller than during degradation of soil organic matter. Isotopic fractionation during hydrogenotrophic methanogenesis, measured in the presence of methyl fluoride, with straw was also smaller than with soil organic matter. The results show that C-13-isotopic analysis after application of rice straw and maize straw is a convenient approach for quantifying carbon flux partitioning during methanogenic degradation of straw and soil organic matter. In our experiments, straw degradation accounted for most of the CH4 production and caused a negative priming effect on the methanogenic degradation of soil organic matter. (c) 2012 Elsevier Ltd. All rights reserved.