Soil factors that contribute to the abundance and structure of the diazotrophic community and soybean growth, yield, and quality under biochar amendment

Abstract Background A 2-year field trial was conducted to test the effect of biochar addition (0, 15, 30, and 45 t hm −2 ) on soil properties, nutrients, diazotrophic community diversity, abundance, structure, soybean growth, yield, quality. Furthermore, we aimed explore responses diazotrophs, grain quality nine environmental factors. Rhizosphere plant samples were collected after harvest. Results Biochar application resulted in a lower bulk density ( γ d but higher total organic carbon (TOC), effective phosphorus (AP) nitrogen (TN). Compared with untreated soil, diversity index bacteria biochar-amended decreased, abundance increased. The microbial remained stable when small amount applied changed as reduced proportion unique nitrogen-fixing bacteria, did not affect that common between soils, increased relative Bradyrhizobium (B9 vs. B0) Sinorhizobium (B18 or B21 involved symbiotic fixation. main components content fatty acids (except for stearic acid) protein oil under application. low treatment (15 promoted growth yield. Redundancy analysis suggested TN greatly influenced structure at phylum genus levels, pH, TOC, NO 3 − -N yield Conclusions Soil diazotroph environment can be improved by targeted farmland implementation based changes physicochemical which would benefit biological N fixation agricultural soils further increase economic benefit. Graphical