Plant and microbial pathways driving plant diversity effects on soil carbon accumulation in subtropical forest
Plant and microbial pathways driving plant diversity effects on soil carbon accumulation in subtropical forest
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植物和微生物途径驱动植物多样性对亚热带森林土壤碳积累的影响
DOI：
10.1016/j.soilbio.2021.108375
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发表时间：
2021-08-06
影响因子：
9.7
通讯作者：
Feng, Xiaojuan
中科院分区：
文献类型：
--
作者：
Jia, Yufu;Zhai, Guoqing;Feng, Xiaojuan
植物物种丰富度（PSR）影响土壤有机碳（SOC）储量。然而，由于土壤有机碳的来源和组成复杂，其驱动机制尚未完全揭示，影响了对植物多样性变化下土壤有机碳动态的准确预测。本文在考虑样地、凋落物和土壤性质的情况下，研究了土壤还原率对亚热带森林土壤有机碳积累的影响。生物标记物和土壤分异用于描述土壤有机碳的植物和微生物组分及其对表层土壤（0-10 cm）和底土（30-40 cm） PSR-SOC关系的影响。我们发现，即使考虑了基质、土壤性质和林龄的影响，PSR也会对两个深度的有机碳浓度产生积极影响。然而，表土和底土的PSR-SOC关系是由不同的途径驱动的。表层土壤中，PSR对有机碳积累具有较强的加性作用，主要受植物源成分（以木质素酚类、轻组分和颗粒有机质为代表）调控，其次是微生物残留。相比之下，PSR对微生物衍生成分（以氨基糖和矿物相关有机质为代表）的积累有积极影响，但对植物残留物没有积极影响，这可能是通过影响土壤中溶解有机质（DOM）和氮有效性（即DOM-微生物途径）来实现的。结果表明，土壤有机碳主要由微生物组分组成，而表层土壤有机碳主要由植物组分组成。这些发现提供了不同深度土壤PSR与有机碳积累之间机制联系的新信息，并强调了PSR对土壤长期碳汇潜力的作用，这可能有助于预测地球系统模型中植物多样性变化下土壤碳动态。
Plant species richness (PSR) is known to affect soil organic carbon (SOC) storage. However, due to the complex origin and composition of SOC, mechanisms driving the PSR-SOC relationship are not yet fully revealed, hampering an accurate prediction of SOC dynamics under changing plant diversity. Here we investigate the effect of PSR on SOC accumulation along a natural PSR and stand age gradient in a subtropical forest with plot, litter and soil properties being considered. Biomarkers and soil fractionation are used to delineate plant and microbial components of SOC and their influences on the PSR-SOC relationship in the topsoil (0-10 cm) versus subsoil (30-40 cm). We show that PSR does positively affect SOC concentrations at both depths even after considering the effects of substrate, edaphic properties and stand age. However, the PSR-SOC relationship is driven by different pathways in the topsoil versus subsoil. In the topsoil, PSR exerts a strong additive effect on SOC accumulation after the positive influence of substrate, edaphic properties and stand age, mainly regulated by plant-derived components (represented by lignin phenols, light fraction and particulate organic matter), followed by microbial residues. By contrast, PSR has a positive effect on the accrual of microbial-derived components (represented by amino sugars and mineral-associated organic matter) but not plant residues likely via affecting dissolved organic matter (DOM) and nitrogen availability in the subsoil (i.e., DOM-microbial pathway). As a result, microbial-derived components dominate SOC variations in the subsoil, while plant-derived components play a more important role in the topsoil. These findings provide novel information on the mechanistic links between PSR and SOC accumulation at different depths and highlight the role of PSR on long-term carbon sink potentials of soils, which may aid in predicting soil carbon dynamics with plant diversity changes in Earth's system model.