Changes in soil microbial diversity and community composition across bahiagrass and rhizome peanut pastures

Rhizoma peanut (RP) (Arachis glabrata Benth.) is a sustainable warm-season perennial forage option in Florida that reduces the reliance on nitrogen (N) fertilizers. This forage legume has been demonstrated to improve bahiagrass (BG) (Paspalum notatum Flüggé) production under low fertilization inputs and promote beneficial soil microorganisms like N2 fixing bacteria. However, whether such microbial characteristics are consistent across different locations and growing seasons is unknown. We applied amplicon sequencing to target soil bacteria and fungi from surface soil (0–20 cm) collected from BG monoculture and BG-RP mixtures in May and July at North, Central, and South farms in Florida. The effect of BG or BG-RP mixtures on bacterial and fungal alpha and beta diversity was impacted by sampling time/location or their interactions. Bacterial alpha diversity was only greater in BG-RP mixtures than BG in May at North farm. Across all farm locations, fungal alpha diversity was greater in the mixtures than BG in July. Rhizoma peanut promoted the relative abundance of the fungal family Didymellaceae, across sampling time and location. However, the effect of RP on Nectriceae was dependent on farm location. Generally, location was a major factor driving the changes in soil microbial community composition, which was explained by soil chemical properties, especially soil pH. Our findings demonstrated that the impact of forage systems on microbial communities in Florida soil is mainly contextual, depending on soil properties, locations, and seasons, a given forage system may differentially affect soil microbial diversity and community composition