The Paradigm of Managing Grasslands for Biofuel Feedstock: An Analysis of Current Practices.

Native grasslands protect the watersheds in which they occur, by improving water quality through increased water infiltration, water yield, and increase water supply by reductions in erosion and sedimentation. In addition, conservation of native prairies is needed as habitat for wildlife including grassland birds and native pollinators. Diverse prairie plantings can also sequester large amounts of carbon while functioning as a source of high energy and low input cellulosic biofuel feedstock. Carbon-negative biofuels from low-input high-diversity grassland biomass could ultimately lead to enhanced use of prairies for biofuel feedstock. The management of prairies for biofuel feedstock can also create changes in the ecosystem services (including but not limited to soil and water conservation services and biodiversity). To study the effects of prairie management, we intensively studied three managed prairie sites in Michigan, through the Great Lakes Bioenergy Research Center (GLBRC), for the effects of two burning practices: burnt (BUR) and unburnt (UNBUR) on the biomass yields and related ecosystem services. Each site has within both, BUR and UNBUR prairie grasses and Switchgrass managed for 6-7 years. These managed systems are monitored for biomass productivity and plant quality, soil and water conservation services (soil stability indices, volume of drainable pores, hydraulic conductivity, and soil moisture characteristics), surface and subsurface temperature conditions, gas fluxes, and insect diversity. Initial results indicate that there were significant differences in the standing biomass yields, soil and water quality indices, soil carbon and nitrogen status, plant diversity, and plant quality. Understanding the effects of these management practices will not only help us predict effects of using prairie grasses for biofuels but may also lead to promising improvement in management practices with increased productivity and enhanced ecosystem services.