Adapting to Climate Change: Multi-Model Insights into Soil Organic Carbon Dynamics in Mediterranean Agroecosystems

The Mediterranean region, warming 20% faster than the global average, is experiencing significant climate change impacts, including rising temperatures, altered precipitation patterns, and increased frequency of extreme weather events. To investigate the implications of these changes on soil organic carbon (SOC) dynamics, we utilized an ensemble of four agricultural system models—EPIC, DSSAT, CropSyst, and APSIM. These models were calibrated and validated using approximately 9,000 observations of crop yields and residues, along with 110 specific SOC measurements, collected from five long-term experiments across a north-to-south pedoclimatic transect in Italy, covering the period from the 1970s to 2022. This comprehensive dataset enabled us to accurately simulate SOC dynamics under varying conditions. We examined three representative concentration pathways (RCPs): RCP2.6 (very low future emissions), RCP7.0 (high future emissions), and RCP8.5 (very high future emissions) for the period 2023-2100, utilizing three bias-corrected EURO-CORDEX climate models with local corrections. Projections revealed significant variations in SOC stocks based on location and agricultural practices.  In Southern Italy, SOC stocks remained stable over time, showing only little variation according to the climate scenario. Conversely, in Central Italy, 30-cm SOC stocks increased until 2070 and then diverged according to the RCPs: a decrease under RCP8.5 (-7.1 t/ha), stabilization under RCP7.0 (+1.0 t/ha), and a sharp increase under RCP2.6 (+11.5 t/ha). In Northeast Italy, SOC stocks decreased under all scenarios, with slightly lower decreases under RCP2.6. Regarding different management systems, conservation agriculture proved to be the most effective in terms of SOC increase or stabilization, while maize and wheat monocultures were the most negatively affected by RCP7.0 and RCP8.5. This study underscores the critical need for location-specific management strategies to address the challenges posed by climate change in the Mediterranean region. Our findings highlight the importance of tailored agricultural practices to mitigate SOC losses and promote soil health under changing climatic conditions.

This research was conducted within the Agritech National Research Center and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022).