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Lei, K.* ; Bucka, F.B.* ; Teixeira, P.P.C.* ; Buegger, F. ; Just, C.* ; Kögel-Knabner, I.*

Balancing organic and inorganic carbon dynamics in enhanced rock weathering: Implications for carbon sequestration.

Glob. Change Biol. 31:e70186 (2025)
Verlagsversion DOI PMC
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
Enhanced rock weathering (ERW) is a promising strategy for CO2 removal via promoting inorganic carbon (IC) sequestration. However, knowledge gaps persist regarding its influence on the largest terrestrial carbon pool, soil organic carbon (SOC) and how these effects evolve as weathering progresses. This study investigated how basalt weathering influences soil carbon fluxes and organic matter (OM) turnover. Over a 6th-month incubation, we applied fresh basalt (fine-sized, olivine-rich) and weathered basalt (coarse- and fine-sized, olivine-depleted) to temperate cropland topsoil, incorporating with 13C-labelled straw. Fresh basalt increases soil pH via rapid H+ neutralization during olivine dissolution, releasing soluble Mg2+ and increasing bicarbonate alkalinity. Combined with continuous carbonic acid dissociation for olivine dissolution, they synergistically enhance dissolved inorganic carbon (DIC) accumulation in soil solution and effluent (~0.4%), promoting soil inorganic carbon (SIC) accrual via carbonate precipitation (~4%). However, rising pH concurrently induces significant SOC losses (~17%), resulting in net C losses of ~13%. As basalt weathering progresses (olivine-depleted), slower H+ neutralization and carbonic acid dissociation during less-reactive Ca-bearing mineral dissolution stabilize soil pH, limiting DIC formation. The released Ca2+ prioritizes SIC accrual via Ca-carbonate precipitation (~4%). Meanwhile, higher specific surface area (SSA) and exchangeable Ca2+ enhance retention and stabilization of both native and straw-derived OC, reducing net C losses (~6%). At both weathering stages, over 95% of total C remaining in soils and effluent exists in organic form. Straw inputs acidify soils by releasing additional free H+ during decomposition, competing with carbonic acid for olivine dissolution and reducing bicarbonate alkalinity, which limits the DIC and SIC accrual at both weathering stages. Since soils continuously receive OM input, understanding the balance between these interactive processes is crucial for optimizing long-term carbon sequestration strategies. Therefore, sustaining SOC by minimizing SOC losses should be prioritized for long-term carbon sequestration, besides IC accrual for ERW, particularly as weathering progresses.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter 13c Isotopic Tracing ; Basalt Weathering ; Carbon Sequestration ; Inorganic Carbon Formation ; Organic And Inorganic Carbon Pools ; Organic Carbon Turnover ; Rising Ph ; Soil Carbon Fluxes; Hydraulic Conductivity; Soil
ISSN (print) / ISBN 1354-1013
e-ISSN 1365-2486
Zeitschrift Global Change Biology
Quellenangaben Band: 31, Heft: 4, Seiten: , Artikelnummer: e70186 Supplement: ,
Verlag Wiley
Verlagsort 111 River St, Hoboken 07030-5774, Nj Usa
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Research Unit Environmental Simulation (EUS)
Förderungen Bayerisches Staatsministerium für Umwelt und Verbraucherschutz