Effect of Water and Nitrogen Coupling on the Characteristics Photosynthesis and Growth in Maize Reproductive Stage in Yuanmou Dry-hot Valleys

• Chunxue WANG, 
• Liangtao SHI, 
• Jiancha LI, 
• Xuewen YUE, 
• Jie WANG, 
• Zhixian PAN, 
• Lei ZHANG, 
• Haidong FANG