Unleashing the sequestration potential of soil organic carbon under climate and land use change scenarios in Danish agroecosystems

Sebastian Gutierrez; Diego Grados; Anders B Møller; Lucas de Carvalho Gomes; Amélie Marie Beucher; Franca Giannini-Kurina; Lis Wollesen de Jonge; Mogens H Greve

doi:10.1016/j.scitotenv.2023.166921

Unleashing the sequestration potential of soil organic carbon under climate and land use change scenarios in Danish agroecosystems

Sci Total Environ. 2023 Dec 20:905:166921. doi: 10.1016/j.scitotenv.2023.166921. Epub 2023 Sep 12.

Authors

Sebastian Gutierrez¹, Diego Grados², Anders B Møller³, Lucas de Carvalho Gomes³, Amélie Marie Beucher³, Franca Giannini-Kurina⁴, Lis Wollesen de Jonge³, Mogens H Greve³

Affiliations

¹ Department of Agroecology, Soil Physics and Hydropedology, Aarhus University, 8830 Tjele, Denmark. Electronic address: seb.gd@agro.au.dk.
² Department of Agroecology, Climate and Water, Aarhus University, 8830 Tjele, Denmark.
³ Department of Agroecology, Soil Physics and Hydropedology, Aarhus University, 8830 Tjele, Denmark.
⁴ Department of Agroecology, Soil fertility, Aarhus University, 8830 Tjele, Denmark.

PMID: 37704130
DOI: 10.1016/j.scitotenv.2023.166921

Abstract

Future global climate changes are expected to increase soil organic carbon (SOC) decomposition. However, the combined effect of C inputs, land use changes, and climate on SOC turnover is still unclear. Exploring this SOC-climate-land use interaction allows us to understand the SOC stabilization mechanisms and examine whether the soil can act as a source or a sink for CO₂. The current study estimates the SOC sequestration potential in the topsoil layer of Danish agricultural lands by 2038, considering the effect of land use change and future climate scenarios using the Rothamsted Carbon (RothC) model. Additionally, we quantified the loss vulnerability of existing and projected SOC based on the soil capacity to stabilize OC. We used the quantile random forest model to estimate the initial SOC stock by 2018, and we simulated the SOC sequestration potential with RothC for a business-as-usual (BAU) scenario and a crop rotation change (LUC) scenario under climate change conditions by 2038. We compared the projected SOC stocks with the carbon saturation deficit. The initial SOC stock ranged from 10 to 181 Mg C ha^-1 in different parts of the country. The projections showed a SOC loss of 8.1 Mg C ha^-1 for the BAU scenario and 6 Mg C ha^-1 after the LUC adoption. This SOC loss was strongly influenced by warmer temperatures and clay content. The proposed crop rotation became a mitigation measure against the negative effect of climate change on SOC accumulation, especially in sandy soils with a high livestock density. A high C accumulation in C-saturated soils suggests an increase in non-complexed SOC, which is vulnerable to being lost into the atmosphere as CO₂. With these results, we provide information to prioritize areas where different soil management practices can be adopted to enhance SOC sequestration in stable forms and preserve the labile-existing SOC stocks.

Keywords: Data-based model; Digital soil mapping; Process-based model; SOC stabilization; Soil carbon deficit; Soil health.