Bacterial community diversity and co-occurrence networks in biochar as a sustainable soil amendment material for apple orchards

Abstract

Biochar amended soils are considered to be a novel concept to improve soil health by providing favorable habitats for microbial activity. This study carried out field experiments to assess the diversity, composition, and co-occurrence networks of soil bacterial communities in the presence of biochar, in order to validate the optimal amount of biochar addition for the practical application of soil improvement in apple orchards in terms of bacterial interactions. The application of appropriate biochar increased bacterial diversity and the prominent presence of copiotroph bacteria was Proteobacteria, and improved the network complexity and cooperative mutualism of the bacterial ecological networks with enhanced stability and environmental resistance. Biochar addition shifts keystone bacteria from anaerobic and cellulose-degrading bacteria to aerobic and nitrogen cycling-related bacteria. Obtained 2 kg/m2 of biochar-amended soil favors micro-environment optimization with the strongest resource utilization and adaptability of the bacterial community. Biochar as a sustainable soil amendment material and 2 kg/m2 biochar addition has the potential to be a viable approach for soil health improvement in apple orchards.