Huang Junsheng, Gao Yuxuan, Peng Yong, Chang Pengfei, Wu Yuntao, Guo Lulu, Luo Jie, Liu Lingli
State Key Laboratory of Forage Breeding-by-Design and Utilization, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Ecology. 2025 Jul;106(7):e70148. doi: 10.1002/ecy.70148.
Soil organic carbon (SOC) predominately originates from the decomposition of plant aboveground and belowground litter, which consists of diverse traits mixed in varying proportions. While numerous studies of litter decomposition have been conducted, the majority have primarily focused on litter mass loss rates. Our comprehension of how the quality and diversity of plant C inputs impact SOC formation remains significantly constrained largely due to the difficulty in their direct measurement at the ecosystem scale. Here, we compiled a global dataset including community-weighted means and variances of plant aboveground structural and chemical traits, which serve as effective indicators of the quality and diversity of C inputs, respectively. We found that smaller community-weighted means of specific leaf area, signifying a lower quality of plant C inputs, could actually enhance SOC accumulation. This finding challenges the common notion that the high microbial carbon use efficiency of labile C inputs would ultimately benefit SOC sequestration. Our findings also showed that greater community-weighted variances of specific leaf area, reflecting more diverse plant C inputs, were positively associated with SOC stocks likely due to the fact that higher C diversity can increase SOC persistence by increasing metabolic costs and diversifying organo-mineral bonds. On the contrary, community-weighted variances of leaf nitrogen content were negatively correlated with SOC stocks. This indicates that litter mixtures with diverse nutrient contents are prone to decomposition possibly due to the complementary effects of nutrients. Notably, the contributions of C input quality and diversity to SOC stocks were more pronounced in colder or drier ecosystems, where the recalcitrance and diversity of C inputs exert a more substantial influence in limiting the microbial decay of SOC. Our results point to the climate-dependent yet important effects of plant C input quality and diversity on SOC stocks across the globe.
土壤有机碳（SOC）主要源于植物地上和地下凋落物的分解，这些凋落物由不同比例混合的各种特性组成。虽然已经开展了大量关于凋落物分解的研究，但大多数研究主要集中在凋落物质量损失率上。由于在生态系统尺度上直接测量植物碳输入的质量和多样性存在困难，我们对植物碳输入的质量和多样性如何影响土壤有机碳形成的理解仍然受到很大限制。在此，我们汇编了一个全球数据集，其中包括植物地上结构和化学特性的群落加权均值和方差，它们分别作为碳输入质量和多样性的有效指标。我们发现，比叶面积的群落加权均值较小，表明植物碳输入质量较低，但实际上可以促进土壤有机碳的积累。这一发现挑战了普遍观点，即易分解碳输入的高微生物碳利用效率最终将有利于土壤有机碳的固存。我们的研究结果还表明，比叶面积的群落加权方差较大，反映了植物碳输入更多样化，与土壤有机碳储量呈正相关，这可能是因为较高的碳多样性可以通过增加代谢成本和使有机-矿物键多样化来提高土壤有机碳的持久性。相反，叶片氮含量的群落加权方差与土壤有机碳储量呈负相关。这表明营养成分不同的凋落物混合物可能由于营养物质的互补作用而易于分解。值得注意的是，碳输入质量和多样性对土壤有机碳储量的贡献在较冷或较干燥的生态系统中更为显著，在这些生态系统中，碳输入的顽固性和多样性在限制土壤有机碳的微生物分解方面发挥着更大的影响。我们的研究结果表明，植物碳输入质量和多样性对全球土壤有机碳储量具有依赖气候但重要的影响。
