Impact of fire-derived charcoal on soil microbial community and diversity

Slash and burn is a traditional and efficient way of removing forest harvest residues in subtropical plantations. However, the impact of fire-derived charcoal on the diversity and composition of soil microbial community was less studied in the field. In this study, three levels of charcoal (nil (B0), single (B1) and double rates (B2)) were applied by transferring charcoal across the plots after slash burning, and soil samples were collected one year after charcoal application. We investigated the diversity and structure of soil bacterial and fungal community by using high-throughput sequencing of bacterial 16S rRNA gene and fungal internal transcribed spacer (ITS). The results showed that soil bacterial and fungal diversity was unaffected by the charcoal application. Charcoal induced taxon-specific shift in relative abundance of bacteria and fungi at the genus level rather than the phyla level. Soil pH played a predominant role in determining OTUs and diversity of soil bacterial community, but not those of soil fungal community. In addition to soil pH, our results also found the importance of soil available P content in structuring soil microbial communities. Collectively, our field study highlighted the importance of charcoal application on the soil bacterial and fungal communities in the subtropical plantation subjected to slash and burn.