Bioenergy is predicted to be a necessary component of a transition to a lower-carbon economy. However, the sustainability of land-intensive bioenergy depends in part on its availability to provide additional ecosystem services. One key ecosystem service is carbon storage in soil over time, a benefit that scales linearly with the amount of land used for bioenergy cultivation.

Replacement of maize grown for ethanol with perennial grasses or other dedicated feedstocks may both prevent carbon losses from the conversion of uncultivated land and offer carbon gains from below-ground storage. The effects of such replacements on energy balance have received less attention, especially relative to their effects on carbon cycling.

In this talk, Blakely will discuss insights from a long record of carbon and energy fluxes from five collocated eddy covariance towers, one over maize (14-year) and one over each of four alternative feedstocks: miscanthus (14-year), switchgrass (8-year), native prairie (8-year), and sorghum (5-year).