Recruitment of beneficial microorganisms by biogas fertilizer enhances the yield and quality of Gynostemma pentaphyllum

Aims

This study investigated how biogas fertilizer enhanced the yield and quality of G. pentaphyllum from a microecological perspective.

Methods

Field experiments were conducted with biogas fertilizer (BS) and without biogas fertilizer (CK). G. pentaphyllum samples, as well as rhizosphere and bulk soil samples, were collected. The yield and quality of G. pentaphyllum were assessed, and the physicochemical properties and microbial communities were analyzed to understand the impact of biogas fertilizer.

Results

The application of biogas fertilizer significantly increased the yield and quality of G. pentaphyllum compared to the CK treatment. Biogas fertilizer application improved soil fertility, altered β-diversity, increased the complexity of the rhizosphere co-occurrence network, and reduced the differences in α-diversity and positive or negative microbial correlations of the co-occurrence network between rhizosphere and bulk soil. Biogas fertilizer application recruited nitrification-associated and plant-growth-promoting-associated microorganisms, enriching the bulk soil and further promoting their colonization in the rhizosphere.

Conclusion

Biogas fertilizer application enhanced the abundance of beneficial microorganisms such as Nitrososphaeraceae, Vicinamibacteraceae, Nitrospiraceae, Chitinophagaceae, and Pyrinomonadaceae in the bulk soil by increasing levels of available potassium (AK), available phosphorus (AP), alkali-hydrolyzable nitrogen (AHN), total phosphorus (TP), total nitrogen (TN), and organic matter (OM). This further facilitated these beneficial microorganisms colonization of the rhizosphere, thereby improving the yield and quality of G. pentaphyllum possibly through enhanced nitrification (e.g., ammonia oxidation) and direct growth promotion.