Reconstructing 60-year soil organic carbon storage in karst watersheds in Southwest China

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena Pub Date : 2025-09-09 DOI:10.1016/j.catena.2025.109434

Zihao Cao , Keli Zhang , Adrian Chappell , Zhuodong Zhang , Zhuoli Zhou , Shizhen Xiao , Jianghu He , Yang Cao

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引用次数: 0

Abstract

Soil organic carbon (SOC) dynamics in fragile karst ecosystems critically influence global carbon budgets but remain poorly quantified, particularly regarding deep sediment archives. This study pioneers high-resolution analysis of depression sediment profiles to reconstruct 60 years of SOC storage (SOCS) dynamics in Southwest China’s karst watersheds. Using sediment core analysis and ¹³⁷Cs dating across three peak-cluster depressions (SJP, DJT, CZ), we: (1) characterized vertical SOC distribution, (2) quantified historical SOCS changes, and (3) established land use impacts through a vegetation succession framework. The results showed that sediment profiles in the SJP, DJT and CZ depressions exhibited consistent vertical SOC distribution. Peak concentrations was observed in the topsoil, gradually decreasing with depth and eventually stabilized in deeper layers. However, spatial heterogeneity was pronounced. DJT and CZ showed higher mean SOC with lower variability, contrasting sharply with SJP’s lower SOC and higher variability. Crucially, SOC density (SOCD) trajectories diverged temporally. SJP transitioned from high early growth (222 % pre-1954) to near-zero accumulation post-1963, while DJT and CZ reversed negative trends (−60.2 % and −53.6 %) to strong positive growth (124.4 % and 6.5 %). Cumulative SOCS over the past 60 years reached 100.4 t (SJP), 57.8 t (DJT), and 3.9 t (CZ), dominated by legacy carbon (70–79 % of 0–200 cm deep pools). Quantification of vegetation succession effects showed that agricultural expansion (forest/shrubs and grassland to cropland) reduces SOC deposition rates by 78–85 %, and ecological restoration (cropland to forest/shrubs and grassland) increases rates by 350–550 %. Despite the time-lagged nature of SOC accumulation, this study demonstrated that ecological restoration significantly enhances carbon sink potential in karst watersheds. Collectively, this work advanced the understanding of SOC dynamics in karst systems, offering empirical evidence for optimizing land management to balance agricultural development and ecological restoration.

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西南喀斯特流域60年土壤有机碳储量重建

脆弱的喀斯特生态系统中土壤有机碳动态对全球碳收支具有重要影响，但其量化仍然很差，特别是在深层沉积物档案中。本研究首次采用高分辨率的洼地沉积物剖面分析方法，重建了中国西南喀斯特流域60年的有机碳储量动态。利用沉积物岩心分析和137Cs测年技术，研究了3个峰群洼地（SJP、DJT、CZ）土壤有机碳的垂直分布特征，量化了土壤有机碳的历史变化，并通过植被演替框架确定了土地利用的影响。结果表明，SJP、DJT和CZ凹陷的垂直有机碳分布基本一致。浓度在表层土壤中达到峰值，随深度逐渐降低，最终在较深层趋于稳定。然而，空间异质性明显。DJT和CZ表现出较高的平均有机碳含量和较低的变率，与SJP较低的有机碳含量和较高的变率形成鲜明对比。关键是，有机碳密度（SOCD）轨迹在时间上是发散的。SJP从早期的高增长（1954年前的222%）过渡到1963年后的近零积累，而DJT和CZ则扭转了负增长趋势（- 60.2%和- 53.6%），转为强劲的正增长（124.4%和6.5%）。过去60年累积SOCS分别达到100.4 t （SJP）、57.8 t （DJT）和3.9 t (CZ)，主要为遗留碳（0-200 cm深碳库的70 - 79%）。植被演替效应量化表明，农业扩张（森林/灌木和草地向农田）使有机碳沉积速率降低了78 ~ 85%，而生态恢复（农田向森林/灌木和草地）使有机碳沉积速率提高了350 ~ 550%。尽管有机碳积累具有时滞性，但生态恢复显著增强了喀斯特流域的碳汇潜力。总体而言，该研究促进了对喀斯特生态系统有机碳动态的认识，为优化土地管理以平衡农业发展和生态恢复提供了经验证据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Catena 环境科学-地球科学综合

CiteScore

10.50

自引率

9.70%

发文量

816

审稿时长

54 days

期刊介绍： Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment. Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.