Study on the Effects of Tobacco Stem Biochar on Soil Organic Carbon and Nitrogen Mineralization

The purpose of this study was to provide reference for the resource utilization of tobacco waste. The soils for test were added with different amounts of tobacco stem biochar (mass fraction of 0.0%, 0.5%, 1.0% and 2.0%) and incubated for 84 days to study the effect of tobacco stem biochar on soil organic carbon (SOC) and nitrogen mineralization characteristics. The results indicated that, compared with the control (mass fraction of 0.0% biochar addition), tobacco stem biochar could promote the soil organic carbon mineralization to certain degree. The accumulative mineralization of SOC was the highest in the 1.0% biochar addition treatment, followed by the 0.5% biochar treatment and 2.0% biochar treatment. The 2.0% biochar treatment could significantly reduce the accumulative mineralization rate of SOC compared with the other treatments, and then promoted the accumulation of SOC. Furthermore, adding tobacco stem biochar in soil had no significant effect on soil nitrogen mineralization rate and nitrification rate. In summary, tobacco stem biochar added to tobacco soil could effectively improve the SOC content at the higher application rate, which would have important implication for the carbon and nitrogen conservation of tobacco soil, and the resource utilization of the waste tobacco stems.