Land cover changes induced spatio-temporal dynamics in soil organic carbon stock across Europe over the past decade (2009-2018)

Soil organic carbon (SOC) is a critical component of the global carbon cycle, serving as the largest terrestrial carbon reservoir and significantly influencing atmospheric greenhouse gas concentrations and climate dynamics. This study investigates SOC dynamics across the European Union and the United Kingdom using the LUCAS Soil datasets from 2009 and 2018, aiming to map SOC levels and assess temporal changes in response to land-use and climate variations. Two methodological approaches were employed: (1) spatiotemporal modeling, integrating data from both 2009 and 2018, and (2) baseline modeling, which used the 2009 SOC map as an environmental covariate to predict 2018 SOC density. Random Forest (RF) and Forward recursive feature selection (FRFS) combined with RF were utilized for SOC prediction. In the spatiotemporal modeling approach, RF achieved an accuracy of R² = 0.41, which improved to R² = 0.43 with FRFS. For the 2009 SOC mapping, RF accuracy was R² = 0.44, increasing to R² = 0.46 with FRFS, while for 2018, RF accuracy was R² = 0.38, improving to R² = 0.39 with FRFS. When the 2009 SOC data were incorporated as a covariate for 2018 predictions, RF achieved R² = 0.44, which further improved to R² = 0.45 with FRFS. The study highlights the impacts of land-use changes, such as afforestation, deforestation, and agricultural intensification, on SOC stocks, and evaluates the effectiveness of sustainable land management practices in enhancing carbon sequestration. The findings provide critical insights into SOC dynamics under varying land-use and climatic conditions, identifying regions where soils may transition from carbon sinks to sources of atmospheric CO₂. This research contributes to evidence-based policy formulation for achieving climate neutrality and sustainable soil management, aligning with the EU Soil Strategy 2030, and underscores the importance of monitoring SOC changes to inform land-use planning and climate mitigation strategies.