Investigation into Soil Microbiome and Nitrogen Cycling Patterns in Warm and Cool Season Turfgrass Systems.

Differences in photosynthetic pathways between warm and cool season turfgrasses lead to divergences in their growth patterns, stress tolerance, and water and nutrient use efficiency. However, whether these differences, together with the corresponding turfgrass management, can substantially modify rhizosphere microbiome and accordingly alter soil nitrogen cycling patterns is still undetermined. Our objective was to evaluate the influence that warm and cool season turfgrasses may exert on soil microbiome and nitrogen cycle. Three warm (Bermuda grass, St. Augustine, and Zoysia grass) and three cool season grasses (Creeping bentgrass, Kentucky bluegrass and Tall fescue) were used to examine soil microbial community compositions and to predict the genetic potential of microbial N transformations. Regardless of grass species, Proteobacteria was dominant, accounting for 44%, followed by Actinobacteria (32%), Acidobacteria (15%) and Bacteroidetes (6%). For fungal community, Ascomycota (44%) was the most abundant phylum, followed by Basidiomycota (8%) and Glomeromycota (4%).Only minor differences were shown between warm and cool season turf systems, with Verrucomicrobia in bacteria, and Chitridiomycota and Glomeromycota in fungi being more abundant in cool season grasses. Of the six grass species, microbial diversity was the highest in tall fescue and the lowest in creeping bentgrass. Despite community compositional changes, the overall nitrogen cycling patterns predicted by PICRUSt remained similar among the turf species.