Effects of bio-organic fertilizer on soil fertility, microbial community composition, and potato growth

The excessive and irrational use of chemical fertilizers poses a series of environmental problems. A growing number of research studies have focused on the application of beneficial microorganisms to reduce the use of chemical fertilizers. Here, potato field experiments were conducted to investigate whether partial replacement of chemical fertilizers with bio-organic fertilizers containing Bacillus velezensis BA-26 had an effect on plant growth, soil fertility, and soil microbial community composition. Three treatment methods were used in this study: organic fertilizer (OF), bio-organic fertilizer (BOF), and chemical fertilizer (CF). The results showed that the biomass and soluble sugar content of potato were significantly increased with BOF treatment. The soil electrical conductivity, available phosphorus (AP), available potassium (AK), urease, and alkaline phosphatase activity also improved with BOF treatment. Further analysis revealed that BOF treatment increases bacterial diversity and reduces fungal diversity. Potentially, pathogenic microbials; such as Fusarium, Verticillium, and Botryotrichum; treated with BOF were significantly decreased compared with CF treatment. Redundancy analysis showed that soil conductivity and AP had significant effects on bacterial and fungal community composition. Thus, the results suggest that the application of bio-organic fertilizer could reduce the use of chemical fertilizers by promoting potato growth, improving soil fertility, and affecting microbial community composition.