1 State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China; School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China. Electronic address: enzaidu@bnu.edu.cn.
2 USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Dr., Riverside, CA 92507, USA.
3 Wageningen University and Research, Environmental Systems Analysis Group, PO Box 47, 6700 AA, Wageningen, the Netherlands; Wageningen University and Research, Environmental Research, PO Box 47, 6700 AA, Wageningen, the Netherlands.
4 Korea Biochar Research Center & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.