Impact of climate warming on soil CO2 emissions: long-term regional-scale simulation analysis in two different cropping systems

Climate change significantly affects soil respiration and biogeochemical cycles, necessitating increasingly resilient cropping systems. This study evaluated soil heterotrophic respiration (Rh) trends in response to climate variability. Using the ARMOSA cropping system model, calibrated and validated with continuous CO2 measurements, we simulated soil CO2 emissions over 40 years for two different cropping systems across 21 soil classes embedded in 37 meteorological grids from the Agri4Cast network in the Emilia-Romagna region. A Random Forest algorithm identified average temperature and annual cumulative precipitation as the main climatic variables influencing Rh. Among different cropping systems and soil types, the correlation analysis between annual average temperature and simulated Rh estimated a CO2 emission response ranging from -0.94 to 10.48 g CO2 per kg of SOC per 1°C increase in annual mean temperature (p < 0.001, Pearson’s r = 0.46). Lastly, the results emphasize that more productive cropping systems, which return larger crop residues to the soil, are more resilient to temperature rising by having a lower mineralization rate preventing from an excess of SOC depletion.