Biomass Yields and the Effect of Harvesting Trees, Shrubs and Native Grasses on Greenhouse Gas (CO2, N2O and CH4) Flux In Riparian Buffers Designed to Provide Biomass for Biofuel Production.

Biofuel feedstock is considered a promising renewable energy source and a viable carbon (C) sequestering option. However, there are concerns about the negative effects of annual crop biofuel feedstock production on the environment. Establishing perennial plant biofuel plantations on marginal cropland such as riparian areas may reduce some of the concerns and help meet the projected demands for biomass. However, frequent harvesting in short-rotation perennial systems may have negative effects on soil C sequestration and greenhouse gas flux which are significantly related to the environmental benefits of riparian buffers. The objective of this study is to quantify biomass produced by a short-rotation management scheme in riparian buffers and to measure the effects of harvesting on CO₂, N₂O and CH₄ flux. We measured plant biomass, fine root biomass, soil C and CO₂, N₂O and CH₄ flux regularly after harvesting and during regrowth in riparian forest buffers and native warm-season grass filters located in the Bear Creek watershed in central Iowa. In this presentation, we will present biomass yields from the sites and the change of CO₂, N₂O and CH₄ flux after harvesting. Results will develop management procedures for harvesting and regenerating biofuel feedstocks in riparian buffers while maintaining their phytoremediation potential.