Simulation of soil organic carbon dynamic in meadow ecosystems under different management practices using CENTURY model

Limited information about long-term changes in soil organic carbon in meadow ecosystems is available. The aim of this study was to simulate the dynamics of soil organic carbon in meadows to assist managers for better understanding the functionality of these ecosystems. CENTURY model was used to simulate the dynamics of soil organic carbon in Dehgolan meadows in Kurdistan province. Climate, soil and management input data for CENTURY model were collected and the model performance was evaluated. Various management scenarios were considered including forage harvesting, low, moderate and heavy grazing, and modification of meadow into wheat and alfalfa field. The results showed that CENTURY model predicted soil organic carbon with appropriate accuracy level (r2 = 0.84, RMSE RMSE 0.05). The model predicted that soil organic carbon content under Scenario 1 (continuing previous management of the harvested forage) in the period from 2014 to 2100 will be reduced by about 15%. The model predicted that soil organic carbon loss in scenario 2 (low grazing) was estimated as low as 2 percent. Reducing the amount of soil organic carbon content under Scenario 3 (moderate grazing), 4 (high grazing), 5 (cultivation of alfalfa) and 6 (cultivation of wheat) was predicted as 23, 25, 47 and 100 percent respectively. Overall, it can be concluded that different management practices have considerable influence on the soil organic carbon dynamics in meadow ecosystems. Low grazing pressure can be suggested as the best management scenario for maintaining soil organic carbon and functionality in meadow ecosystems.