Institute of Soil and Water Resources and Environmental Science, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China.
Chair of Ecosystem Functioning and Services, Institute of Ecology, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany.
Sci Total Environ. 2022 Mar 10;811:152163. doi: 10.1016/j.scitotenv.2021.152163. Epub 2021 Dec 5.
Inputs of available organic materials into soil alter the decomposition of soil organic matter (SOM), a process called priming effect. Organic carbon (C) inputs in terrestrial ecosystems are common from various sources (e.g. rhizodeposits, plant residues, microbial necromass) simultaneously, but their interactions as well as mutual effects on SOM decomposition are unknown because multisource partitioning of pools and fluxes was not available. A dual-isotope approach (identical materials except for straw being possessed two C abundances) was adopted to partition total CO emission from three C sources: SOM, glucose and straw. Cumulative CO efflux was quantified into straw-derived (558 μg C g), glucose-derived (480 μg C g) and SOM-derived (58 μg C g) CO during the first 7 days of incubation. Glucose or straw addition induced positive SOM priming, whereas glucose combined with straw resulted in higher SOC loss than that induced by single addition of glucose or straw after day 7. The Spearman's correlation showed that the interactions between glucose and straw shifted from increased CO evolved during their intensive decomposition (days 1 to 3) to mutual constraint on mineralization during the late stage (days 5 to 7). This study provides evidences for the suitability of the dual-isotope approach to partition multiple sources of CO fluxes and C pools, and evaluates their individual or mutual contributions to SOM priming, thus, implicating C sequestration in terrestrial ecosystems.
输入土壤中的可用有机物质会改变土壤有机物质（SOM）的分解，这个过程称为激发效应。陆地生态系统中有机碳（C）的输入通常来自多种来源（例如根分泌物、植物残体、微生物残体），但它们的相互作用以及对 SOM 分解的相互影响是未知的，因为池和通量的多源分区不可用。采用双同位素方法（除了秸秆具有两种 C 丰度外，相同的材料）来划分三种 C 源（SOM、葡萄糖和秸秆）的总 CO 排放。在培养的前 7 天内，定量了秸秆衍生（558μg C g）、葡萄糖衍生（480μg C g）和 SOM 衍生（58μg C g）CO 的累积 CO 通量。葡萄糖或秸秆的添加诱导了正 SOM 激发，而葡萄糖与秸秆的组合在第 7 天后导致 SOC 损失高于单独添加葡萄糖或秸秆所引起的损失。Spearman 相关性表明，葡萄糖和秸秆之间的相互作用从它们密集分解期间（第 1 天至第 3 天）释放的 CO 增加转变为后期（第 5 天至第 7 天）矿化的相互制约。本研究为双同位素方法适用于划分多种 CO 通量和 C 池的来源提供了证据，并评估了它们对 SOM 激发的单独或相互贡献，从而暗示了陆地生态系统中的碳固存。
