Estimation of soil organic carbon changes in turfgrass systems using the CENTURY model

Soil organic C (SOC) directly affects soil quality by influencing aeration and water retention and serving as a major repository and reserve source of plant nutrients. Limited information is available concerning the long-term SOC changes in turfgrass systems. The CENTURY simulation model offers an opportunity to predict long-term SOC trends based on mathematical representations of C-cycling processes in the soil-plant systems. The objectives of this study were to (i) evaluate the ability and effectiveness of the CENTURY model to simulate the long-term SOC dynamics in highly managed turfgrass ecosystems and (ii) simulate long-term SOC changes for golf course fairway and putting green scenarios with the CENTURY model. The CENTURY model simulations near Denver and Fort Collins, CO, indicate that turfgrass systems can serve as a C sink following establishment. Model estimates are that 23 to 32 Mg ha(-1) SOC were sequestered in the 0 to 20 cm below the soil surface after about 30 yr. Historic soil-testing data from parts of 16 golf courses with age ranging from 1 to 45 yr were used to compare with the simulated results. Model predictions of organic C accumulation compared reasonably well with observed SOC, with regression coefficients of 0.67 for fairways and 0.83 for putting greens. Our results suggest that the CENTURY model can be used to simulate SOC changes in turfgrass systems and has the potential to compare C sequestration under various turf management conditions. Simulation results also suggest that warming temperatures have greater degree of influence on SOC in turf systems compared with native grasslands.