中文关键词水稻土碳固持易利用态碳碳负荷¹³C同位素示标记激发效应 英文关键词paddy soilcarbon sequestrationreadily available carboncarbon loading¹³C-labelled glucosepriming effect

作者	单位	E-mail
童瑶瑶	江西理工大学资源与环境工程学院, 赣州 341000 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125	tongyaoyao0206@sina.com
王季斐	江西理工大学资源与环境工程学院, 赣州 341000 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
祝贞科	中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
邓扬悟	江西理工大学资源与环境工程学院, 赣州 341000	tosang@foxmail.com
陈珊	中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125 中南林业科技大学环境科学与工程学院, 长沙 410004
葛体达	中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
袁红朝	中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125
吴金水	中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室, 长沙 410125

中文摘要 易利用态有机碳是土壤微生物的重要碳源，影响土壤有机碳的矿化和累积过程，而易利用态碳源的输入量尤其是相对于土壤微生物生物量碳的不同输入负荷，对土壤有机碳的矿化影响机制尚不明确.因此，本研究采取室内模拟培养实验，选择不同浓度梯度添加［0.5、1、3、5倍微生物量碳（MBC）］¹³C-葡萄糖，分析葡萄糖-C的矿化特征及其激发效应.结果表明，葡萄糖-C矿化率随着外源碳添加量的增加而显著增加；葡萄糖-C向快库、慢库分配的比例也分别与碳添加量呈指数关系（R²=0.99，P<0.05和R²=0.99，P<0.05）.在高添加量处理（3×MBC、5×MBC）中，葡萄糖的添加抑制土壤原有有机碳的矿化，即表现出负激发效应；而在低添加量处理（0.5×MBC、1×MBC）中，表现为正激发效应，60 d培养结束后累积激发效应分别为160.0 mg·kg^-1和325.1 mg·kg^-1.相关性分析结果表明在培养实验前期，累积激发效应主要受MBC、MBN和DOC的影响，而在后期主要β-葡糖苷酶、几丁质酶和铵态氮的影响.因此，稻田土壤有机碳矿化和激发效应与易利用态有机碳添加的碳负荷密切相关，并通过微生物量和酶活性调控土壤碳的矿化过程.本研究对于揭示稻田有机碳累积行为与推动农业可持续发展具有重要的科学意义. 英文摘要 Available carbon is the most active part of the soil carbon pool. It is also the main carbon source of soil microbes and plays an important role in the processes of soil organic carbon mineralization and accumulation. However, the mechanisms are still not clear how soil organic carbon mineralization and its priming effect (PE) are affected by different input levels of readily available carbon, based on the growth requirements of microbes in paddy soil. In this study, an incubation experiment was conducted by adding different levels (0.5, 1, 3, and 5 times of MBC) of exogenous source organic carbon (¹³C-glucose) to the soil. The mineralization dynamics of labile organic carbon and its priming effect was investigated. The mineralization rate of glucose-C increased significantly with the increasing carbon loading level. The distribution of glucose-C into rapid and slow C pools was also exponentially correlated with the carbon loading (R²=0.99, P<0.05 and R²=0.99, P<0.05, respectively). Negative PE was observed at high carbon loading (3×MBC and 5×MBC); while positive PE was induced by low carbon loading (0.5×MBC and 1×MBC). The cumulative PE was 160.0 mg·kg^-1 and 325.1 mg·kg^-1, respectively, at the end of the incubation. Redundancy analysis showed that the main factors affecting the cumulative PE were MBC, MBN, and DOC at the initial glucose mineralization stage, while β-glucosidase, chitinase, and ammonium nitrogen were the main factors at later stages. Therefore, the readily available carbon loading has an important effect on the organic carbon mineralization and PE in paddy soil. Higher carbon loading was good for the accumulation of organic carbon sequestration in paddy soil. This study is of great scientific significance for revealing the activity of organic carbon in paddy fields and for its contribution to the development of sustainable agriculture.

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