The effect of amending soils with biochar on the microhabitat preferences of Coptotermes formosanus (Blattodea: Rhinotermitidae)

Biochar has attracted worldwide attention owing to its potential for mitigating greenhouse gas emissions, improving soil properties, increasing plant growth and so on. While, the assessment of a substantial amount of security is required to determine before biochar is more extensively applied. Our goal was to evaluate the security of biochar by determining the effect of biochar on the preference of soil arthropods for microhabitats. In this study, we examined the effect of varying amounts of biochar on the preference of the Formosan subterranean termite (Coptotermes formosanus) to microhabitats. In addition, we analyzed key soil characteristics to explore their relevance to the termite preferences. Our results found that when compared with 0% (control soil), there was no preference when 2.5% and 5% of biochar were applied. The application of >5% biochar repelled the termites, which then left these soils. Their fresh weight and rates of survival also decreased. The soil pH increased, but the humidity decreased when >5% of biochar was applied. Soil bacteria composition when biochar was amended at 20% also differed from 0% and 2.5% applications. The relative abundance of Cellvibrio and Flavisolibacter in 20% were significantly higher than 0% and 2.5%, while the relative abundance of Burkholderia, Candidatus_Solibacter, Dyella, Edaphobacter, Fulvimonas and Occallatibacter were significantly lower than them. And the functional results predicted by Bugbase suggested that biochar application can cause an increase in the soil potentially pathogen phenotype. In conclusion, our research indicated that biochar can affect the preference of termites for microhabitats and changes in the characteristics of soil might cause changes in these preferences. In addition, our results suggest that soil that has been amended with >10% biochar has the potential to control termites.