Tradeoffs in ecosystem services of prairies managed for bioenergy production

The use of prairie biomass as a renewable source of energy may constitute an important opportunity to improve the environmental sustainability of managed land. To date, assessments of the feasibility of using prairies for bioenergy production have focused on marginal areas with low yield potential. Growing prairies on more fertile soil or with moderate levels of fertilization may be an effective means of increasing yields, but increased fertility often reduces plant community diversity. At a fertile site in central Iowa with high production potential, we tested the hypothesis that nitrogen fertilization would increase aboveground biomass production but would decrease diversity of prairies managed for bioenergy production. Over a three-year period, we measured aboveground biomass production after plant senescence and species and functional-group diversity in June and August for multispecies mixtures of prairie plants that received no fertilizer or 84 kg N ha year. We found that nitrogen fertilization increased aboveground biomass production, but with or without fertilization, the prairies produced a substantial amount of biomass: averaging 12.2 and 9.1 Mg ha in fertilized and unfertilized prairies, respectively. Primary researcher and author Provided input at all stages and supervised the work