The Abundance and Deficiency Evaluation of Soil Available B and Zn in Baoshan Tobacco Growing Areas

• CHENG Changxin, 
• YAN Hui, 
• YIN Xingsheng, 
• LI Qiang, 
• YANG Yingming, 
• NIE Xin, 
• LI Li, 
• WANG Chao