Spatial Variability Characteristics and Evaluation of Soil Fertility in the Main Winter-early Vegetable Production Areas of Yuanmou, Yunnan

• TIAN Shihan, 
• DENG Yishu, 
• BAO Li, 
• LI Jiarong, 
• SU Youbo, 
• ZHANG Naiming, 
• XIA Yunsheng