Native Grass and Forb Establishment in Post-Agricultural Soil

Restoration of degraded and abandoned agricultural land in arid and semiarid climates is a global problem. The erratic patterns of precipitation these lands experience makes restoration of a plant community difficult. Application of supplemental irrigation and inoculation with arbuscular mycorrhizal fungi (AMF) are two restoration techniques that have been suggested to overcome deficits in natural precipitation. The effects and the interactions of irrigation and seeding date on the ground cover of intended species and unintended exotic species were tested in a post-agricultural restoration experiment in south-central Colorado, USA. The greatest ground cover of intended species and lowest ground cover of unintended species was observed when seeds were sown in May and were irrigated at higher rates. Results suggest that the timing of sowing as well as the amount of irrigation applied are important in arid post-agricultural restoration. The effects of different AMF inoculation and water treatments on plant biomass were also tested in a manipulative greenhouse experiment. Plant biomass was not greater when inoculated with AMF, which suggests that the use of AMF in post-agricultural soil may not be worth the additional costs of implementation