Projected climate change impacts on future soil organic carbon dynamics and wheat yields under different agricultural management strategies for two contrasting environments in Iran

Understanding how agricultural practices and climate change impact crop yields and soil organic carbon (SOC) is crucial for maintaining agroecosystem functioning. In this study, MONICA model was used for assessing the impacts of agricultural strategies: conventional (CON), organic (ORG), and integrated (INT), and crop rotation systems: fallow-wheat (F-W), maize-wheat (M-W), sesame-wheat (S-W), and mung bean-wheat (B-W) on the yield and above ground biomass (AGB) of aforementioned crops and the change in SOC stocks for the semi-arid region of Ahvaz (Iran). We also assessed the impacts of CO2 emissions of societal development pathways SSP245 (480 ppm) and SSP585 (600 ppm) on future (2030–2060) changes in yield, AGB, and SOC for a M-W rotation under the mentioned agricultural strategies in the contrasting climate zones of Ahvaz and Torbat-Heydareye. MAE and NRMSE values of the calibrated model were 0.4 Mg ha –1 and 12% for wheat yield and 0.5 Mg ha –1 and 10.4% for wheat AGB. The low NRMSE values for SOC simulations (7.7%) indicated that MONICA accurately reproduced observed SOC. Projected wheat yield and AGB, and SOC contents, influenced by elevated CO2 levels and rising temperatures. In future scenarios, CO₂ enrichment and warming improved yield and SOC in the semi-arid cold climate (Torbat-Heydareye) but reduced both in the semi-arid warm climate (Ahvaz). Climate change had a stronger impact on SOC under CON than under organic-based management strategies at both sites. This highlights the need to assess agricultural strategies regionally, considering climate projections and soil types.