Below-ground carbon inputs contribute more than above-ground inputs to soil carbon accrual in a bioenergy poplar plantation
Background and aims Soil organic carbon (SOC) accrual is central to the discussion on active atmospheric CO2 removal strategies, but it requires a clear understanding of the mechanisms driving new SOC formation. SOC is formed from the decomposition of above- and below-ground plant inputs, yet their accurate quantification remains a major challenge. In the current study the in-growth soil core and δ13C methods were combined to quantify the net C input from single or combined above- and below-ground parts of a poplar (Populus) bioenergy plantation. Methods Three different mesh sizes were used for the in-growth cores in four different treatments designed to estimate the relative contributions of above-ground litter fall, fine roots and mycorrhizae (C3 input from the poplar) to the new C formation in cores filled with a C4 soil, by applying a mass balance equation. Results Soil C formation was higher in the treatments with roots as compared to the treatments with above-ground C inputs only (29 vs 16 g C m−2), despite the disproportionally lower root inputs as compared to above-ground C inputs (34 vs 175 g C m−2 y−1). Soil C formation from different sources (above- and below-ground) was additive; i.e. the observed soil C formation in the combined treatment was the sum of those in the single soil C input treatments. As a result, below-ground C-inputs had a high conversion efficiency to SOC of 76%. Above-ground plant inputs had a very low SOC formation efficiency of 9%, and were presumably mainly mineralized by microorganisms. Conclusion The higher soil C accumulation rates from below-ground C inputs are particularly important in bioenergy plantations where the above-ground biomass is frequently removed for biomass and energy production.
Source (journal)
Plant and soil. - 's-Gravenhage, 1949, currens
's-Gravenhage : 2019
0032-079X [print]
1573-5036 [online]
434 :1-2 (2019) , p. 363-378
Full text (Publisher's DOI)
Full text (open access)
Research group
Project info
System analysis of a bio-energy plantation: full greenhouse gas balance and energy accounting. (POPFULL)
ICOS Flanders: Ecosystem Infrastructure for Integrated Carbon Observing System.
Global Ecosystem Functioning and Interactions with Global Change.
Publication type
Publications with a UAntwerp address
External links
Web of Science
Creation 31.10.2018
Last edited 09.10.2023
To cite this reference