Cao Xiaoqing, Xu Yuting, Wang Fei, Zhang Zhili, Xu Xiaoniu
Anhui Provincial Key Laboratory of Forest Resources and Silviculture, Anhui Agricultural University, Hefei, 230036, China.
School of Forestry and Landscape Architecture, Anhui Agricultural University, Hefei, 230036, China.
Sci Rep. 2024 Dec 30;14(1):31778. doi: 10.1038/s41598-024-81847-4.
Exploring the components of soil organic carbon (SOC) and aggregate stability across different elevations is crucial to assessing the stability of SOC in subtropical forest ecosystems under climate change. In this study, we investigated the spatial variation of active carbon (C) compositions, aggregate distribution, and stability in Chinese fir (Cunninghamia lanceolata) plantations across an elevation gradient from 750 to 1150 m a.s.l. on the northern foothills of the Dabie Mountains, China. The results showed that macroaggregates accounted for more than 80% of all fractions at different elevations. In the 0-10 cm soil layer, the macroaggregates, mean weight diameter (MWD), geometric mean diameter (GMD), and SOC exhibited a U-shaped distribution trend with increasing elevation. Conversely, in the 10-50 cm soil layer, these indicators showed a consistent increasing trend. Similarly, the contents of easily oxidizable carbon (EOC) and particulate organic carbon (POC) gradually increased with increasing elevation. Microbial biomass carbon (MBC) and silt + clay C exhibited a unimodal distribution pattern along the elevational gradient, peaking at 850 m a.s.l., which is mainly related to soil pH and C/N ratio. Across all elevations, The silt + clay C was significantly higher than that of macro- and micro-aggregate C. Macro- and micro-aggregate C, and dissolved organic carbon (DOC) were significantly positively correlated with MWD. The results demonstrated that elevation and soil layer have significant effects on SOC and aggregate stability. The physical protection of silt + clay fractions and the active carbon pools may be the main mechanisms for organic carbon preservation in the Dabie Mountains. These results contribute to further deepening the impact of elevation on climate change and the C cycling of forest ecosystems.
探究不同海拔土壤有机碳（SOC）的组成成分和团聚体稳定性，对于评估气候变化下亚热带森林生态系统中SOC的稳定性至关重要。在本研究中，我们调查了中国大别山北麓海拔750至1150米的杉木（Cunninghamia lanceolata）人工林中活性碳（C）组成、团聚体分布和稳定性的空间变化。结果表明，不同海拔下大团聚体占所有组分的比例均超过80%。在0-10厘米土层中，大团聚体、平均重量直径（MWD）、几何平均直径（GMD）和SOC随海拔升高呈U形分布趋势。相反，在10-50厘米土层中，这些指标呈一致的增加趋势。同样，易氧化碳（EOC）和颗粒有机碳（POC）的含量也随海拔升高而逐渐增加。微生物生物量碳（MBC）和粉粒+粘粒碳沿海拔梯度呈单峰分布模式，在海拔850米处达到峰值，这主要与土壤pH值和碳氮比有关。在所有海拔下，粉粒+粘粒碳显著高于大团聚体碳和微团聚体碳。大团聚体碳、微团聚体碳和溶解有机碳（DOC）与MWD显著正相关。结果表明，海拔和土层对SOC和团聚体稳定性有显著影响。粉粒+粘粒组分的物理保护作用和活性碳库可能是大别山有机碳保存的主要机制。这些结果有助于进一步深化海拔对气候变化和森林生态系统碳循环的影响。
