Influence of soil phosphorus levels on rhizosphere fungal communities in managed subtropical perennial Bahiagrass

Soil phosphorus (P) is a critical limiting nutrient influencing primary productivity, particularly in agricultural systems. Rhizosphere fungal communities play an important role in nutrient cycling, especially P cycling, and therefore are presumed to respond strongly to soil P levels. This study investigates the influence of soil available P levels on rhizosphere fungal communities of perennial Bahiagrass – one of the most dominant forage grass species in the subtropical climate, emphasizing the relationship between soil P and fungal communities and functional potentials. Our results showed that soil Mehlich-1 P (M-1 P) was the most significant soil factor influencing fungal community composition (beta diversity), followed by total P and the N/P ratio (P < 0.05). Additionally, the soil N/P ratio emerged as the strongest and most consistent predictor of fungal alpha diversity at both taxonomic and functional levels. At the functional group level, N/P ratio, pH, and plant P positively influenced fungal functional richness, whereas soil moisture showed a moderate negative relationship. The relative abundance shifts in fungal functional groups, such as decline in Dung Saprotrophs with increasing M1-P levels, indicate potential changes in ecological functions associated with soil P availability. Understanding these relationships can inform management strategies that promote a resilient fungal community and support Bahiagrass-dominated agricultural production systems through best management practices.