Short-term calcium peroxide application promotes soil microbial interactions to improve peanut yield in acidic soils.

The deterioration of soil microorganisms stands as a key barrier to the sustainable cultivation of peanut. Peroxides such as hydrogen peroxide (H2O2) and calcium peroxide (CaO2) with antimicrobial efficacy may inhibit soil pathogens and improve microbial community, but their effects on the soil properties, microbiome and peanut yield are still unclear. In this study, a field experiment was conducted to investigate the effects of CaO2 (CP, with application rate of 4.5 t ha-1) and H2O2 (HP, with application rate of 22.5 t ha-1) and no peroxide application (CK) on physicochemical properties, microbial communities and network structures of acidic soils in which peanut had been cultivated for 13 years. Compared with CK, calcium peroxide application significantly increased soil pH. Hydrogen peroxide showed a similar trend, but not significant. Principal co-ordinates analysis (PCoA) indicated that peroxides application significantly affected the fungal community structure, while it had a weaker impact on the bacterial community. With peroxides application, soil harmful fungus Fusarium and the fungal functional group associated with plant pathogen declined. Network co-occurrence analysis showed that peroxides enhanced bacterial network interactions, with bacterial stability increasing markedly by 2.19- and 1.40-fold in calcium peroxide and hydrogen peroxide treatments, respectively. Peanut yield was correlated with the microbial network properties, and significantly increased by 31.7% in calcium peroxide. Random forest model analysis further revealed that bacterial stability, soil pH, bacterial negative cohesion, and complexity were key factors for peanut yield. In conclusion, short-term calcium peroxide application increased soil pH and bacterial stability, thereby promoting peanut yield in acidic soils.