Grassland production performance and photosynthetic characteristics under different alfalfa densities and grass bean mixed sowing

• TENG Ze, 
• ZHANG Yongliang, 
• ZHANG Yuxia, 
• YU Tiefeng, 
• CHEN Weidong, 
• SUN Hao, 
• LIU Huan, 
• TANG Yuting