Effects of abiotic components induced by biochar on microbial communities

Abstract

Soil microorganisms play an important role on ecosystems and are influenced by a variety of abiotic and biotic variables. The influence of biochar on the microbial community has been reported, but its mechanism modifying soil microbial distribution is less understood. In this paper, biochar was physically separated from soil, and the abiotic characteristics generally recognised influencing soil microbial communities were examined. The microbial community structure was assessed via denaturing gradient gel electrophoresis (DGGE). The influence of abiotic components including available N, Olsen P and extractable K, pH and C/N induced by biochar on soil microbial communities was compared by canonical correspondence analysis (CCA). Results indicated that biochar fostered more fungi and stimulated bacteria growth in the adjacent soil. Biochar particles at three sampling times exhibited the similar microbial community composition, although it was also impacted by temporal factors. Phylogenetic distributions of the operational taxonomic units (OTUs) could be divided into the following eight groups: Bacillaceae, Gemmatinomadetes, Sphingomanas, Acidobacteria, Proteobacteria, Chloroflexaceae, Actibacteria (similarity > 95%) and unknown (similarity < 85%). CCA revealed the great contribution of C/N, Olsen P and extractable K to fungi growth, and C/N and Olsen P to actinomycete abundance. The presence of biochar not only induced increase of available nutrients but also increased microbial biomass and diversity, which indicated beneficial effects on soil microorganisms and soil fertility.