[Effect of Biochar on Changes of the Temperature Sensitivity of Soil Respiration and Bacterial Community Structure]

To explore the effects of biochar on the temperature sensitivity of soil respiration and microbial community structure, the soil was subjected to an indoor culture test under two major treatments which were control (CK) and the addition of 3% (mass ratio) biochar (BC). Each major treatment contained four temperature conditions. We analyzed the changes in soil CO₂ emission, the content of different soil organic carbon, and the characteristics of the soil bacterial community. The results showed that:①The input of biochar to soil respiration under various temperature conditions was promoted in the early stage and inhibited in the later stage, and after 14 days of cultivation, the input of biochar significantly reduced the temperature sensitivity Q₁₀ values of soil respiration. ② For soil organic carbon fractions, the decline rate of the content of soil inert organic carbon under the CK treatment increased with increasing temperature, and was sensitive to the changes in temperature. However, the input of biochar significantly reduced the temperature sensitivity of the soil inert organic carbon, and narrowed its decline rate under each temperature condition. The decline rate did not increase with increasing temperature. ③The 16S rDNA high-throughput sequencing results showed that at the end of the cultivation, the relative abundance of Massilia in the soil of the CK treatment decreased with increasing temperature, and the input of biochar significantly increased its temperature sensitivity, making the decline rate increase. In contrast to Massilia, the relative abundance of Haliangium in soil of the CK treatment increased significantly with increasing temperature, and the input of biochar significantly reduced its temperature sensitivity, rendering the difference of relative abundance between each temperature condition not significant. This study shows that the input of biochar can significantly reduce the temperature sensitivity of soil respiration, which is related to decreased temperature sensitivity of soil inert organic carbon, and the change in the relative abundance of Massilia and Haliangium after the input of biochar.