3000年来不同土地利用类型土壤密度组分的碳动态和路径：来自13C自然丰度的见解

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena Pub Date : 2025-03-24 DOI:10.1016/j.catena.2025.108968

Mingxu Xu , He Jiao , Yalu Zhang , Baowei Su , Shuangwen Yi , Huan Zhang , Chao Gao

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引用次数: 0

摘要

通过稳定碳同位素（13C）确定的碳(C)流动路径为陆地生态系统中的碳动态提供了见解。然而，C路径如何随时间顺序、土地利用和土壤深度的不同组合而变化仍然不确定。为了填补这一空白，进一步阐明土壤有机碳（SOC）库的稳定机制和功能差异，我们采用时空替代方法建立了4种土地类型的3000年序列，并对长江沿岸连续样地的5个土壤剖面进行了采样。我们还使用了土壤密度分数(fLF，自由光分数；oLF，遮挡光分数；DF：致密分数；以及MF（矿物组分）和δ13C天然丰度，以加深对C转化相关生物地球化学过程的认识。土壤有机碳（SOC）含量呈现出一致的时间序列动态，在2000a后呈现先上升后下降的趋势。在土壤土壤和块状土壤中观察到类似的动态，强调了植物来源的碳输入对碳积累的重要性。oLF持续增加，δ13C值最低，反映了物理遮挡稳定机制的作用。时序稳定性与质量比(比例>；与其他馏分相比，95%)的MF表现出更强的C稳定能力。旱作轮作减少了中游草地与其他组分之间的C可达性和C流动，旱作轮作在中游草地内积累了最多的C。C的总体路径是从轻组分（oLF和fLF）到重组分（DF和MF）（oLF→fLF→DF→MF），流向更深的底土。随着深度的增加，重质馏分的δ13C富集趋势比轻质馏分更为明显，这可能与重质馏分的来源和成分不同有关。我们通过δ13C和C路径在更精细细分的代表性有机碳池中提供了C动态的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

$Carbon dynamics and pathways in soil density fractions across different land-use types over 3000 years: Insights from 13C natural abundance$

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Carbon dynamics and pathways in soil density fractions across different land-use types over 3000 years: Insights from 13C natural abundance

Carbon (C) flow pathways, as identified through stable C isotopes(¹³C), provide insights into C dynamics within terrestrial ecosystems. However, how C pathways change in response to varying combinations of chronosequence, land use, and soil depth remains uncertain. To fill this gap and further elucidate stability mechanisms and functional disparities in soil organic carbon (SOC) pools, we establish a 3000-year sequence for four land types using space-for-time substitution and sample five soil profiles from serial plots along the Yangtze River. We also use soil density fractions (fLF, free light fraction; oLF, occluded light fraction; DF, dense fraction; and MF, mineral fraction) and δ¹³C natural abundance to deepen our understanding of biogeochemical processes related to C transformation. Consistent chronosequence dynamics in SOC content are revealed across bulk soil and three fractions (fLF, DF, and MF), with an initial increase and then a decrease occurring after 2000a. Similar dynamics observed in fLF and bulk soil highlight the importance of plant-derived C input in C accumulation. The oLF continuously increases and has the lowest δ¹³C value, reflecting the role of a physical occlusion stabilization mechanism. Chronosequence stability and the mass ratio (proportion > 95 %) of MF reveal its superior C stabilization capacity compared with other fractions. Through decreased C accessibility and C flows between MF and other fractions, paddy–dryland rotation accumulates the most C within the MF. The overall C pathway is from light (oLF and fLF) to heavy (DF and MF) fractions (oLF → fLF → DF → MF), flowing to the deeper subsoil. With increasing depth, the trend in δ¹³C enrichment of heavy fractions is more pronounced than for light fractions, potentially because of their distinct sources and constituents. We provide insights into C dynamics through δ¹³C and C pathways in more finely subdivided, representative SOC pools.

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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.