生态系统碳循环对大气二氧化碳浓度和全球气候变化有重要调节作用，已成为当前地球系统科学与全球变化研究的热点和前沿之一。作为地壳中的第二大元素，硅对全球生物活动和碳循环具有重要影响。
我院土壤圈演化研究组开展了草地和森林等生态系统硅循环与植硅体碳汇及其调控机制研究(图1, 2)。结果表明，受降水和植物物种组成影响，典型草原植物硅含量显著高于草甸草原。过度放牧等引起的草地退化降低土壤中有效硅和其它非晶质硅的含量及储量。竹林植硅体固碳能力是其它森林的3~12倍。草地退化是中国草地植硅体固碳能力较低的主要原因。保护草地等生态系统以及耕地硅磷肥施加等可使当前全球植硅体固碳速率增加一倍。
在草地和耕地等陆地生态系统碳循环研究基础上，揭示了硅在促进生物和非生物胁迫下植物生物量碳积累中的作用，阐明了生物硅等非晶质硅以及硅-铁-铝相互作用促进土壤有机碳稳定化的机制，完善了陆地生态系统碳循环的硅调控机制(图1)。这些成果为完善全球碳循环模式提供了基础数据和理论依据，有助于指导未来国家和全球范围碳增汇减排实践。
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图1 陆地硅-碳循环的耦合过程与反馈机制 |
图2 植硅体结构与植硅体碳分布模型 |
该工作得到了国家自然基金委优秀青年科学基金项目和国家自然基金委国际合作项目等项目联合资助。相关成果如下：
1. Xiaodong Zhang, Zhaoliang Song*, Qian Hao, et al. Storage of soil phytoliths and phytolith-occluded carbon along a precipitation gradient in grasslands of northern China. Geoderma, 2020, 364, 114200.
2. Xiaomin Yang, Zhaoliang Song*, Changxun Yu, et al. Silicon fractionation in broadleaf and conifer forests of northern China: Implications for silicon biogeochemical cycle. Geoderma, 2020, 361: 114036.
3. Zimin Li, Fengshan Guo, Jean-Thomas Cornelis, Zhaoliang Song*, et al. Combined silicon-phosphorus fertilization impacts carbon occlusion in phytoliths of rice plants. Front. Plant Sci., 2020, 11: 67. doi: 10.3389/fpls.
4. Xiaodong Zhang, Zhaoliang Song*, Qian Hao, et al. The phytolith storage of forest litter in southern China: Implications for long-term biogeochemical carbon sink. Front. Plant Sci., 2019, doi: 10.3389/fpls.2019.00581.
5. Shaobo Sun, Tao Che*, Zhaoliang Song*, et al. Water and carbon exchange of alpine meadow ecosystem in northeastern Tibetan Plateau was energy-limited. Agr. Forest Meteorol., 2019, 275, 283–295.
6. Zhaoliang Song*, Congqiang Liu, Karin Müller, et al., 2018. Silicon regulation of soil organic carbon stabilization and its potential to mitigate climate change. Earth-Sci. Rev. 185, 463-475.
7. Zichuan Li, Zhaoliang Song*, Zhifeng Yan, et al., 2018. Silicon enhancement of estimated plant biomass carbon accumulation under abiotic and biotic stresses. A meta-analysis. Agron. Sustain. Dev., 38(3), 26. Doi: 10.1007/s13593-018-0496-4.
8. Xiaomin Yang, Zhaoliang Song*, Hongyan Liu, et al., 2018. Phytolith accumulation in broadleaf and conifer forests of northern China: implications for phytolith carbon sequestration. Geoderma, 312, 36–44.
