【Objective】The experiment aimed at exploring the effect of Bacillus subtilis on soil fertility and to determine the appropriate dosage of Bacillus subtilis.【Method】The main cultivars of K326 in Hunan Province were used as test materials,and field experiments were conducted to study the different dosage of Bacillus subtilis(CK:0 kg/hm~2; T1:15 kg/hm~2; T2:30 kg/hm~2; T3:45 kg/hm~2) effect on the nutrient content in the soil of tobacco planting.【Result】The difference between 45 days after transplanting and af...