Regular biochar and bacteria-inoculated biochar alter the composition of the microbial community in the soil of a Chinese fir plantation

Abstract

Biochar is a promising material for the improvement of soil quality. However, studies on biochar have mostly been carried out in laboratory conditions or have focused on agricultural aspects. The impacts of the application of biochar on soil characteristics and related ecological processes of the forest ecosystem have not been fully resolved. In this study, we investigated the effects of regular biochar and bacteria-loaded biochar on the microbial communities in the bulk soil and the rhizosphere soil of an annual Chinese fir plantation. In early spring (April), the two types of biochar were added to the soil at the rates of 2.22 t•ha-1, 4.44 t•ha-1, 6.67 t•ha-1, 8.89 t•ha-1, and 11.11 t•ha-1 by ring furrow application around the seedlings, and soil samples were collected at the end of autumn (November). The results showed that biochar addition increased the soil nutrient content and promoted the growth and diversity of soil microbial communities. The diversity of soil fungi was significantly increased, and the diversity of soil bacteria was significantly decreased. Principal component analysis under the different biochar types and application rates demonstrated that microbial communities differed significantly between the treatments and controls and that the effect of biochar on the microbial community of the bulk soil was more significant than that of the rhizosphere soil. Under the same dosage, the effect of bacteria-loaded biochar on soil was more significant than that of regular biochar.