ABSTRACT Plant carbon (plant-C) added to soil can accelerate or inhibit the decomposition of native soil organic matter by inducing positive or negative priming effects. The effect of different types of plant-C on the mineralization of the added carbon and of soil organic carbon (SOC) could contribute to understanding the priming effect. An incubation experiment was carried out at 20°C under dark conditions for 28 days. Soluble-C, lipid-C, and recalcitrant-C derived from 13C-labeled maize straw were added at amounts equivalent to 25%, 50%, and 200% of microbial biomass carbon to two soils containing relatively high (159 g kg−1, H-SOC) and low (13 g kg−1, L-SOC) contents of total SOC. Results showed that mineralization rates varied greatly across soils and plant-C types. Independently of the type of plant-C, less than 30% of the added C was mineralized by the end of the incubation. A greater priming effect was observed in the H-SOC than in the L-SOC soil. Recalcitrant-C caused a greater priming effect than lipid-C and soluble-C in the L-SOC soil. Moreover, the type of priming effect caused by lipid-C and soluble-C in the L-SOC soil changed when the amount of added-C increased from 50% to 200% of microbial biomass carbon. Results indicate that SOC and the type of plant-C are important factors controlling the priming effect. Specially, N and other nutrients released during mineralization of recalcitrant-C stimulated microbial activity, causing a greater priming effect.

中文翻译：

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来自玉米秸秆的植物碳成分影响两种 Mollisol 中的引发过程

摘要 添加到土壤中的植物碳 (plant-C) 可以通过诱导正面或负面的启动效应来加速或抑制原生土壤有机质的分解。不同类型的植物碳对添加碳和土壤有机碳 (SOC) 矿化的影响有助于理解启动效应。孵育实验在 20°C 黑暗条件下进行 28 天。将来源于 13C 标记的玉米秸秆的可溶性 C、脂质 C 和顽固性 C 以相当于微生物生物量碳的 25%、50% 和 200% 的量添加到两种含有相对较高 (159 g kg−1 , H-SOC) 和低 (13 g kg-1, L-SOC) 总 SOC 含量。结果表明，不同土壤和植物-C 类型的矿化率差异很大。独立于植物 C 的类型，到培养结束时，少于 30% 的添加 C 被矿化。在 H-SOC 中观察到比在 L-SOC 土壤中更大的启动效应。在 L-SOC 土壤中，顽固性 C 比脂质 C 和可溶性 C 引起更大的启动效应。此外，当添加的-C量从微生物生物量碳的50%增加到200%时，L-SOC土壤中脂质-C和可溶性-C引起的启动效应类型发生了变化。结果表明SOC和植物-C的类型是控制启动效应的重要因素。特别是，顽固性C矿化过程中释放的N和其他营养物质刺激了微生物活动，产生了更大的启动效应。在 L-SOC 土壤中，顽固性 C 比脂质 C 和可溶性 C 引起更大的启动效应。此外，当添加的-C量从微生物生物量碳的50%增加到200%时，L-SOC土壤中脂质-C和可溶性-C引起的启动效应类型发生了变化。结果表明SOC和植物-C的类型是控制启动效应的重要因素。特别是，顽固性C矿化过程中释放的N和其他营养物质刺激了微生物活动，产生了更大的启动效应。在 L-SOC 土壤中，顽固性 C 比脂质 C 和可溶性 C 引起更大的启动效应。此外，当添加的-C量从微生物生物量碳的50%增加到200%时，L-SOC土壤中脂质-C和可溶性-C引起的启动效应类型发生了变化。结果表明SOC和植物-C的类型是控制启动效应的重要因素。特别是，顽固性C矿化过程中释放的N和其他营养物质刺激了微生物活动，产生了更大的启动效应。