Reed biochar improved the soil functioning and bacterial interactions: A bagging experiment using the plantation forest soil (Fraxinus chinensis) in the Xiong'an new area, China

Common reed (Phragmatic australis) is a vigorous growing wetland plant that forms dense monotypic stands in the Baiyang Lake in the Xiong'an New Area (XNA) of Hebei Province in north China. As a result of untimely harvesting, it has recently developed into an endogenous invasive plant. We assessed the feasibility of reed biochar addition in soils from the ash tree (Fraxinus chinensis) plantation to evaluate the impact of biochar addition on the soil multi-functionality with a bag trial using a greenhouse incubation approach. The soil nutrient turnover was promoted by increasing the abundance of key functional genes of cbbL, nifH, nirK, and pqqC at the early stage. Bacterial taxa tended to be convergent communities irrespective of biochar addition. Path analysis showed that soil variables and bacterial network parameters were positively correlated with soil function in general, whereas alpha diversity has shown an almost opposite relationship. Biochar increased the number of keystone taxa at the treatment's middle stages and improved the network's stability. The whole primary succession of the bacterial communities remarkably homogenous dispersal, contributing to 80% of bacterial community assemblies, which indicates little competitive pressure. Collectively, these results point to a role for biochar addition in enhancing soil functions in ash tree plantations, which can be considered cleaner production to contribute to the greening efforts of the plantation forest sustainability.