Natural Vegetation Restoration Is More Beneficial to Soil Surface Carbon Sequestration on Loess Plateau

The Loess Plateau of China is a unique geographical unit characterized by extensive loess distribution, serious soil erosion, low vegetation coverage and high soil carbonate content. Since the 1950s, the Chinese government has made great efforts to control soil erosion and restore vegetation, including large-scale tree plantation in the 1970s, integrated soil erosion control in the 1980s and 1990s, and the “Grain for Green Project” in the 2000s. Currently, the ecological restoration of the Loess Plateau has produced remarkable achievements: increasing vegetation coverage, decreasing soil erosion and enhanced ecosystem services. Soil carbon sequestration is a critical index for evaluating the efficiency of ecological restoration. Previous studies have unanimously indicated that ecological restoration can significantly promote soil carbon storage. However, most of these studies were focused on soil organic carbon (SOC), with only a few on soil inorganic carbon (SIC). These studies showed that the mean density and storage of SIC in the 0-100 cm soil layer on the Loess Plateau is more than twice that of the SOC pool and represents 21.66% of the total SIC storage in China. Therefore, the SIC pool of the Loess Plateau may make an important contribution to the national carbon budget. Moreover, natural vegetation restoration and tree plantation are the two most important measures for ecosystem restoration. However, few studies have compared the effects of the two contrasting measures on SOC and SIC sequestration or have further used soil organic and inorganic carbon isotopes to analyze the inherent sequestration mechanism. Dr. JIN Zhao from the State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment and his collaborators examined two neighboring small watersheds on the Loess Plateau with similar topographical and geological backgrounds (Fig.1). Since 1954, natural Natural Vegetation Restoration Is More Beneficial to Soil Surface Carbon Sequestration on Loess Plateau