[Research progress on the effects of biochar application on soil fauna community]

Soil fauna is an indispensable component of soil biotic communities and an important biological driver controlling soil ecological processes. Exploring the effect of biochar on soil fauna community and their relationship, is of great significance to understand the ecological process and services of soil ecosystem. We reviewed the changes and possible mechanisms of soil fauna community to biochar application. The effect of biochar application on soil fauna was caused directly by the difference of raw material, carbonization temperature, and application amount, and indirectly by the changes of biotic factor, including changes of plant physiological characters and microbe biomass, and changes of abiotic parameters (e.g. soil physiochemical characters). The growth, reproduction and behavior of soil fauna could be promoted under low amount of biochar application (mass ratio <5%). In contrast, toxicity effect occurred with a heavy application (>10%). Meanwhile, activities of soil fauna would affect the stability of biochar, and its ecological and environmental role. A road map for future researches about biochar and soil fauna interaction must focus on long-term field studies, spatial and temporal variation, merge of multi-discipline, and comprehensive analysis and prediction.