Changes in nitrogen application and conservation reserve program area from cellulosic biofuel production in the United States

Abstract

Biomass production from agricultural residues and dedicated bioenergy crops to meet the cellulosic biofuel mandate will change the land-allocation in the United States as well as the application rate of nitrogen. We extend a previously used model in three ways: First, we incorporate land in the Conservation Reserve Program (CRP) as a potential source for bioenergy crops. Second, we include high removal coefficients for agricultural residue removal and lastly, we assess changes in the nitrogen load at the county level. We quantify those effects under various scenarios differing by bioenergy crop (switchgrass and miscanthus), production costs, agricultural residue removal rates, and biofuel mandates. Consistent with previous research, our results indicate that little CRP land is converted to bioenergy crop production which is due to relatively high CRP payments compared to biomass yields. In addition, the majority of the cellulosic biofuel mandate can be met with agricultural residues which require more nitrogen in the corn and wheat producing regions in the U.S., i.e., the Midwest and the Great Plains, due to nutrient replacement. Our findings can inform future research to assess the effects of spatially shifting nitrogen application at the watershed level due to cellulosic biomass production.