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摘要：以甘肅省甘南尕海则岔自然保护区内的未退化、轻度退化、中度退化及重度退化的湿地为研究对象，采用野外取样和室内测试相结合的方法，应用室内矿化培养实验，分析了植被退化过程中土壤在不同土层（0～10、10～20、20～40 cm）中的有机碳矿化特征。结果表明，植被退化程度、培养时长、温度高低和土层深度均对土壤有机碳矿化速率有显著影响。不同退化程度土壤有机碳矿化量均随着土层加深而降低，未退化[475.74 CO2 /（mgC/g）] > 重度退化[329.302 CO2 /mgC/g）] > 轻度退化[291.50 CO2 /（mgC/g）] > 中度退化[253.11 CO2 /mgC/g）]。不同退化程度土壤有机碳矿化量均随着培养时间的变长而降低，且平均在2～6 d下降速度较快，平均在13 d左右后下降速度平缓，基本保持不变。按照CO2-C 释放速率变化程度，将矿化曲线划分为快速矿化（平均约12 d）、缓慢矿化（平均约26 d）和平衡矿化三个阶段，其中快速矿化阶段主要为活性碳矿化。双库一级动力学方程可以较好的拟合植被退化中土壤有机碳矿化过程，不同退化程度土壤有机碳矿化量均随土层加深而降低，浅层和未退化土壤矿化能力较强，对难分解有机碳库的利用程度较高，可以有效促进碳循环，提高土壤固碳能力，在研究全球碳循环时应给予重视。
关键词：土壤有机碳矿化；植被退化；双库一级动力学方程
中图分类号：X171.4 文献标志码：A 文章编号：1001-1463（2019）03-0018-08
doi：10.3969/j.issn.1001-1463.（2019）03.004
Abstract：This paper studies the characteristics of organic carbon mineralization of soil in different soil layers（0～10、10～20、 20～40 cm） in the process of vegetation degradation by using the method of field sampling combined with indoor testing to study the non-degraded， slightly degraded， moderately degraded and severely degraded wetlands in Gahai Zecha Nature Reserve in Gansu Province. The results show that vegetation degradation degree， culture duration and soil depth have significant effects on soil organic carbon mineralization rate. The accumulated mineralization amount of soil organic carbon decreases with soil depth at different degradation degrees （low non-degradation[475.74 CO2/（mgC/g）]> severe degradation[329.30 CO2/（mgC/g）]> mild degradation[291.50 CO2/（mgC/g）]> moderate degradation[253.11 CO2/（mgC/g）]. The accumulated mineralization of soil organic carbon at the same degradation degree decreased with the longer culture time， and the average decline rate was faster at 2～6 days， and the average decline rate was flat after 13 days， basically unchanged. The mineralization curve was divided into three stages， namely rapid mineralization （about 12 days in average）， slow mineralization（about 26 days in average） and balanced mineralization， according to the variation degree of CO2-C release rate. Double library first order kinetics equation could better fit vegetation degradation in soil organic carbon mineralization process. Organic carbon cumulative mineralization amounts in different degrees of degradation of soil all reduced in deeper soils. Shallow and not degraded soils had stronger mineralization ability and higher utilization of organic carbon pool which was the difficult to decompose， could effectively promote the carbon cycling， improve the ability of soil carbon sequestration， and should obtain full attention when studying global carbon cycle.
