植物生态学报 ›› 2018, Vol. 42 ›› Issue (12): 1211-1224.DOI: 10.17521/cjpe.2018.0202

• 研究论文 • 上一篇    

湖南东部植被恢复对土壤有机碳矿化的影响

辜翔1,张仕吉1,刘兆丹1,李雷达1,陈金磊1,王留芳1,方晰1,2,3,*()   

  1. 1 中南林业科技大学生命科学与技术学院, 长沙 410004
    2 南方林业生态应用技术国家工程实验室, 长沙 410004
    3 湖南会同杉木林生态系统国家野外科学观测研究站, 湖南会同 438107
  • 收稿日期:2018-08-16 修回日期:2018-11-01 出版日期:2018-12-20 发布日期:2019-04-04
  • 通讯作者: 方晰 ORCID: 0000-0003-1236-2335
  • 基金资助:
    国家林业公益性行业科研专项(201504411);国家自然科学基金项目(30771720);国家自然科学基金项目(31170426)

Effects of vegetation restoration on soil organic carbon mineralization in the east of Hunan, China

GU Xiang1,ZHANG Shi-Ji1,LIU Zhao-Dan1,LI Lei-Da1,CHEN Jin-Lei1,WANG Liu-Fang1,FANG Xi1,2,3,*()   

  1. 1 School of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China
    2 National Engineering Laboratory of South China Forestry Ecology Applicable Technologies, Changsha 410004, China
    3 Huitong National Field Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystem in Hunan Province, Huitong, Hunan 438107, China
  • Received:2018-08-16 Revised:2018-11-01 Online:2018-12-20 Published:2019-04-04
  • Contact: FANG Xi ORCID: 0000-0003-1236-2335
  • Supported by:
    Supported by the National Forestry Public Welfare Industry Research Project.(201504411);the National Natural Science Foundation of China(30771720);the National Natural Science Foundation of China(31170426)

摘要:

为阐明中亚热带植被恢复对土壤有机碳(SOC)稳定性的影响机制, 采用空间代替时间方法, 在湘东丘陵区选取檵木(Loropetalum chinense)-南烛(Vaccinium bracteatum)-杜鹃(Rhododendron simsii)灌草丛(LVR)、檵木-杉木(Cunninghamia lanceolata)-白栎(Quercus fabri)灌木林(LCQ)、马尾松(Pinus massoniana)-柯(Lithocarpus glaber)-檵木针阔混交林(PLL)、柯-红淡比(Cleyera japonica)-青冈(Cyclobalanopsis glauca)常绿阔叶林(LAG)作为一个恢复系列, 采用室内恒温培养(碱液吸收法)测定SOC矿化速率及其累积矿化量(Cm), 结合主成分和逐步回归方法分析Cm、SOC矿化率与植被因子和土壤因子的关系。结果表明: (1)不同植被恢复阶段SOC矿化速率随着培养时间呈现基本一致的变化趋势, 培养初期矿化速率较高, 且快速下降, 培养中后期缓慢下降并趋于平稳, 倒数方程能很好地拟合不同植被恢复阶段SOC矿化速率与培养时间的关系。(2)植被恢复显著提高各土层SOC矿化速率和Cm, LAG显著高于其他3个植被恢复阶段, LAG 0-40 cm土层Cm比LVR、LCQ、PLL分别高出359.06%-716.31%、112.38%-232.61%、94.40%-105.74%。(3) 4种植被恢复阶段0-10、10-20、20-30、30-40 cm土层SOC矿化率分别为2.13%-4.99%、3.42%-4.18%、4.05%-4.64%、4.02%-5.64%, 但不同植被恢复阶段之间差异不显著。(4)植被恢复过程中, Cm的变化主要受土壤全氮(TN)含量、根系生物量的驱动, 土壤TN含量、根系生物量可分别解释Cm变异的96.9%、0.9%。而土壤C:N是SOC矿化率的主要调控因子, 可单独解释SOC矿化率变异的49.4%。表明植被恢复促进了SOC矿化, 降低了SOC中矿化C的比例, 有利于提高土壤固C能力; 随着植被恢复, 土壤TN含量和根系生物量增加是影响Cm的主要因子, 而土壤SOC的质量差异是影响SOC矿化率的主要因子。

关键词: 中亚热带地区, 植被恢复, 有机碳矿化, 植被因子, 土壤因子

Abstract:

Aims Soil organic carbon (SOC) mineralization and its controlling factors are critical for understanding the mechanisms that regulate C storage and loss processes. Our objectives were to accurately assess the impacts of vegetation restoration on SOC mineralization and to illustrate the underlying mechanism of changes in SOC stability with vegetation restoration in the mid-subtropical region of China.

Methods Four types of vegetation communities (Loropetalum chinense-Vaccinium bracteatum-Rhododendron mariesiiscrub-grass-land (LVR), Loropetalum chinense-Cunninghamia lanceolata-Quercus fabri shrubbery (LCQ), Pinus massoniana-Lithocarpus glaber-Loropetalum chinense coniferous-broad leaved mixed forest (PLL) and Lithocarpus glaber-Cleyera japonica-Cyclobalanopsis glauca evergreen broad-leaved forest (LAG) ) were selected for a successional sequence of the secondary forest in a hilly region of eastern Hunan Province, China. Soil samples (0-40 cm) were collected from four depths (0-10, 10-20, 20-30 and 30-40 cm). SOC mineralization was determined by the laboratory incubation method (alkali absorption method). Principal component analysis and stepwise regression were applied to analyze the relationships between SOC cumulative mineralization (Cm), the percentage of Cm to SOC content and vegetation factors and soil factors.

Important findings 1) SOC mineralization rate displayed similar trends during the four restoration stages: during the early incubation period, SOC mineralization was high and decreased fast, and then the rate decreased slowly and tend to stabilize during the middle and late periods. The pattern was well fitted with the reciprocal equation. 2) SOC mineralization rate and Cm increased significantly with the vegetation restoration stage with the LAG having both the highest SOC mineralization rate and the highest Cm. In 0-40 cm soil layer, Cm in LAG soil was 359.06%-716.31%, 112.38%-232.61%, 94.40%-105.74% higher than that in LVR, LCQ, PLL soils, respectively. 3) The percentage of Cm to SOC content were 2.13%-4.99%, 3.42%-4.18%, 4.05%-4.64%, and 4.02%- 5.64% in 0-10, 10-20, 20-30, 30-40 cm soil layers, respectively. However, there was no significant difference in the percentage of Cm to SOC content among the different restoration stages. 4) Among different vegetation restoration stages, total nitrogen (TN) content and root biomass (RB) were the key factors affecting Cm. TN content and RB together explained 97.8% variations in Cm, of which TN content explained 96.9%. However, C:N was the dominant factor affecting the percentage of Cm to SOC content and it alone explained 49.4% variation. Vegetation restoration promoted SOC mineralization rate and reduced the percentage of Cm to SOC content in our study, which might be related to the changes in RB and soil nutrient during vegetation restoration.

Key words: mid-subtropical region of China, vegetation restoration, soil organic carbon mineralization, vegetation factor, soil factor