Effects of Biochar on Tobacco-planting Soil Quality and Flue-cured Tobacco Growth

Based on the local fertilization practice, by adding different proportions of biochar (2.25, 4.50 t/hm²), a field experiment was designed to study the potential effect of biochar application on tobacco-planting soil quality and flue-cured tobacco growth. The results indicated that the application of biochar influenced the physical and chemical properties of the tobacco-planting soil,,especially the topsoil (0-10 cm). In the 0-10 cm layer, compared with the control, application of biochar increased the soil field capacity, soil porosity, pH, organic matter and the content of soil CEC. Meanwhile, biochar application improved the contents of soil NO₃^--N, available phosphorous and available potassium and reduced the soil bulk density and soil NH4+-N content. The high biochar treatment showed more significant effects. In the process of flue-cured tobacco growth, adding biochar could promote the absorption of potassium, while reduce the absorption of phosphorus and nitrogen and decrease dry matter accumulation of tobacco after topping. At 90 days after transplanting, compared with the control, root dry weight significantly decreased by 5.58%, 7.05% at 2.25 and 4.50 t/hm² biochar application levels respectively. Dry mass of stems and leaves were not significantly different between the control and the biochar treatments.