Fig. 5. (A) Carbon content of each of compartments C₁, C₂, and C₃ in the wheat–fallow (WF) rotation using adjusted k values and model-derived additions that maintain original SOC content at 51 yr. See Table 7 and Fig. 3 and 4 for model information. (B) Trend of total soil organic C (SOC) in each rotation as calculated using the three-compartment model with model-derived additions that maintain the original SOC at 51 yr. Additions needed to maintain the original SOC are greater for the WF than the wheat–oat–barley–hay–hay (WOBHH) rotations