Abstract

Soil organic carbon (SOC) sequestration represents a critical climate change mitigation strategy, yet its future potential under changing environmental conditions remains uncertain. This study employed the CENTURY and RothC biogeochemical models to simulate SOC dynamics across diverse agroecosystems under Representative Concentration Pathways (RCP) 4.5 and 8.5 climate scenarios through 2100. The models were calibrated using long-term experimental data from 45 sites spanning temperate, tropical, and semi-arid regions. Under RCP4.5, both models predicted continued SOC sequestration potential averaging 0.8-1.2 t C ha⁻¹ yr⁻¹ in croplands with optimized management practices. However, under RCP8.5, elevated temperatures (3-5 °C increase) reduced sequestration rates by 35-50% due to enhanced decomposition, with some regions becoming net carbon sources by 2080. CENTURY model simulations showed greater sensitivity to temperature changes, predicting 15% lower SOC stocks compared to RothC under high warming scenarios. Precipitation changes exhibited variable effects, with +20% precipitation increasing SOC by 8-12% in water-limited systems but decreasing SOC by 5-8% in humid regions due to enhanced leaching. Cover crop adoption and no-tillage practices maintained positive sequestration rates even under RCP8.5, achieving 0.4-0.6 t C ha⁻¹ yr⁻¹ compared to -0.2 t C ha⁻¹ yr⁻¹ under conventional management. Model ensemble results suggest that global SOC sequestration potential could range from 1.2 to 2.8 Gt C yr⁻¹ by 2050 depending on climate trajectory and management adoption rates. These findings underscore the critical importance of implementing adaptive management strategies to maintain soil carbon sinks under future climate conditions.