Soil carbon sequestration for climate change mitigation: Mineralization kinetics of organic inputs as an overlooked limitation

A - Papers appearing in refereed journals

Berthelin, J., Laba, M., Lemaire, G., Powlson, D. S., Tessier, D., Wander, M. and Baveye, C. 2022. Soil carbon sequestration for climate change mitigation: Mineralization kinetics of organic inputs as an overlooked limitation. European Journal of Soil Science. 73 (1), p. e13221. https://doi.org/10.1111/ejss.13221

AuthorsBerthelin, J., Laba, M., Lemaire, G., Powlson, D. S., Tessier, D., Wander, M. and Baveye, C.
Abstract

Over the last few years, the question of whether soil carbon sequestration could contribute significantly to climate change mitigation has been the object of numerous debates. All of these debates so far appear to have entirely overlooked a crucial aspect of the question. It concerns the short-term mineralization kinetics of fresh organic matter added to soils, which is occasionally alluded to in the literature, but is almost always subsumed in a broader modelling context. In the present article, we first summarize what is currently known about the kinetics of mineralization of plant residues added to soils, and about its modelling in the long run. We then argue that in the short run, this microbially-mediated process has important practical consequences that cannot be ignored. Specifically, since at least 90% of plant residues added to soils to increase their carbon content over the long term are mineralized relatively rapidly and are released as CO2 to the atmosphere, farmers would have to apply to their fields 10 times more organic carbon annually than what they would eventually expect to sequester. Over time, because of a well-known sink saturation effect, the multiplier may even rise significantly above 10, up to a point when no net carbon sequestration takes place any longer. The requirement to add many times more carbon than what one aims to sequester makes it practically impossible to add sufficient amounts of crop residues to soils to have a lasting, nonnegligible effect on climate change. Nevertheless, there is no doubt that raising the organic matter content of soils is desirable for other reasons, in particular guaranteeing that soils will be able to keep fulfilling essential functions and services in spite of fast-changing environmental conditions.

KeywordsClimate change mitigation; Soil carbon modeling; Microbial activity; Soil functions
Year of Publication2022
JournalEuropean Journal of Soil Science
Journal citation73 (1), p. e13221
Digital Object Identifier (DOI)https://doi.org/10.1111/ejss.13221
PubMed IDBB
Open accessPublished as bronze (free) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeS2N - Soil to Nutrition [ISPG]
The Rothamsted Long Term Experiments [2017-2022]
Output statusPublished
Publication dates
Online01 Feb 2022
PublisherWiley
ISSN1351-0754

Permalink - https://repository.rothamsted.ac.uk/item/987y5/soil-carbon-sequestration-for-climate-change-mitigation-mineralization-kinetics-of-organic-inputs-as-an-overlooked-limitation

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Under embargo until 01 Feb 2023

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