Short-term impact of fire-deposited charcoal on soil microbial community abundance and composition in a subtropical plantation in China

Slash burning is a common and efficient way of removing forest harvest residues in subtropical plantations. However, few field studies have assessed the impact of fire-deposited charcoal on the diversity and composition of soil microbial communities. In this study, we manipulated the amount of charcoal left in plots after slash burning in a Pinus massoniana plantation of subtropical China. Soil samples were collected from 0 to 10 cm depth one year after charcoal application or removal. We investigated the diversity and composition of soil bacterial and fungal communities by high-throughput sequencing. The results showed that a taxon-specific shift in the relative abundances of bacteria and fungi at the genus level was observed after one year of fire-derived charcoal application, while soil bacterial and fungal diversity were not affected. Soil pH played a predominant role in determining the abundance of operational taxonomical units and diversity of soil bacteria, but not of the soil fungal community. In addition to soil pH, the amount of available phosphorus in soil played an important role in structuring soil microbial communities. Collectively, our findings highlight the importance of fire-deposited charcoal to soil bacterial and fungal communities in subtropical plantations subjected to slash burning.