Effects of Nitrogen Fertilizer Topdressing on Nitrogen Use and Yield and Quality of Early Maturing Maize Intercropping in Tobacco Fields

• RUAN Zhenjing, 
• ZHOU Jing, 
• LI Hai, 
• WANG Qiangfeng, 
• FU Jingdong, 
• JI Yunzuo, 
• AN Tongxin