1. Institute of Plant Nutrition and Resource, Beijing Academy of Agriculture and Forestry Sciences (BAAFS), Beijing 100097, China
2. Department of Agricultural & Biological Engineering, University of Florida, 1741 Museum Road, Gainesville, Florida 32611-0570, United States
3. Ministry of Forestry Bioethanol Research Center, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
4. School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States