Effects of land use/cover changes on soil organic carbon stocks in Qinghai-Tibet Plateau: A comparative analysis of different ecological functional areas based on machine learning methods and soil carbon pool data

Abstract

Abstract Understanding the process of land use/cover changes (LUCC) can provide experience on the enhancement of soil organic carbon(SOC) stocks and carbon sequestration potential for different areas. We divided Qinghai Province into four functional areas and used machine learning method and soil carbon pool dataset to compare and analyze the drivers of LUCC and the changes in SOC stocks effected by LUCC. Topography and climate changes are the main drivers affecting LUCC in four natural areas, while soil factors and population changes do not cause significant effects. The total SOC stocks in Qinghai was increased by 71.18 Tg C and 107.19 Tg C in 0-30cm and 0-300cm layers, respectively, and the highest SOC stocks within 0-300cm were in Pastoral area. Desert and Gobi area had the lowest SOC stocks in both 0-30cm and 0-300cm layers. SOC stocks increased in both 0-30cm and 0-300cm layers only in Sanjiangyuan Natural Reserve, while the Desert and Gobi area showed a decrease in both over 30 years. Grassland changes caused a significantly SOC stocks changes. The initial and original SOC stocks of pre-LUCC may influence the SOC stocks in post-LUCC. The response of SOC stocks changes to LUCC was varies in different areas.