Simulating Soil Organic Carbon Dynamics under Climate Change Scenarios in an Arid Ecosystem

Abstract

Land use change and climate have significant effects on decomposition of soil's organic carbon and ultimately carbon dioxide (CO 2 ) emissions from the soil into the atmosphere. The Rothamsted carbon model is one of the most widely used models in studies related to soil carbon sequestration which is applied in many studies to investigate the effect of climate change on soil carbon storage. The purpose of the present study is to investigate the effect of land uses of native rangeland, restoration rangeland, cattle-grazed rangeland, agro-ecosystem, as well as simulating the effect of two climate scenarios on soil carbon storage using the Roth C model on the four mentioned type of lands in the Markazi Province, Iran for 33 years . In this study, 102 soil samples were taken to determine soil organic carbon and other soil characteristics and SOC stock were calculated at a depth of 0-30 cm in each land use. The results showed that due to the restoration rangeland, after 8 years, there was a significant increase in SOC stock (17.76%), and after 17 years, in farm use, there was a (3.47%) decrease in the amount of SOC stock compared to the local rangeland of the area (control rangeland) in the Markazi Province, Iran. The simulation results of RothC model also showed that SOC stock in 2050 in treatment of the local, the restoration, the cattle-grazed and the cultivated rangelands and also due to the climate change will decrease 6.28%, 16.09%, 13.12%, and 7.28%, respectively.