Can commercial AMF inoculum improve prairie restoration? -- Colonization and growth effects of fungi on sand prairie plants and smooth brome in field soils

Abstract

Arbuscular mycorrhizal fungi (AMF) affect the species composition, structure, and function of prairie ecosystems, but prairie restorations are frequently located in sites with depauperate AMF communities. In this greenhouse study, four native sand prairie species (Schizachyrium scoparium, Elymus canadensis, Monarda punctata, and Aster ericoides) and an invasive grass (Bromus inermis) were grown in unsterilized field soils and treated with two brands of commercial AMF inoculum. Inocula were applied at the manufacturers' suggested rate and at two times the recommended rate. Soil was collected from two locations: a meadow enrolled in the Conservation Reserve Program (CRP) that is dominated by Bromus inermis, and from an active agricultural field. At the rates used in this study, the commercial inoculum did not significantly increase biomass or percent colonization of any grass species. However, both biomass and percent colonization in Aster were influenced by inoculum type, although treated individuals were not significantly different from control groups in pairwise comparisons. Increased percent colonization in all three grasses and increased biomass in the native grasses was observed in individuals grown in the CRP soil. In terms of prairie restoration, an existing soil fungal community appears to be more productive in terms of percent colonization and plant biomass than an addition of commercial inocula.