Effect of nitrogen application on soil nitrogen content, root growth and nitrogen uptake of a meadow in the Wugong Mountains

• Xiao-juan Hou, 
• Fei Yu, 
• Cheng Cui, 
• Kai Li, 
• Zhi Li, 
• Xue-ling Zhang, 
• Xiao-min Guo, 
• De-kui Niu