The Implications of Growing Bioenergy Crops on Water Resources, Carbon and Nitrogen Dynamics

The bioenergy crops, Corn, Miscanthus and switchgrass have a potential to meet future energy demands in the US and mitigate climate change by partially replacing fossil fuels. However, the large-scale cultivation of these bioenergy crops may also impact climate change through changes in albedo, evapotranspiration (ET), and greenhouse gas (GHG) emissions. Whether these climate effects will mitigate or exacerbate climate change in the short and long terms is uncertain. The uncertainties come from our incomplete understanding of the effects of expanded bioenergy crop production on terrestrial water and energy balance, carbon and nitrogen dynamics, and their interactions. This study aims to understand the implications of growing large scale bioenergy crops on water resources, carbon and nitrogen dynamics in the United States using a data- modeling framework (ISAM) that we developed. Our study indicates that both Miscanthus and Cave-in-Rock switchgrass can attain high and stable yield over parts of the Midwest, however, this high production is attained at the cost of increased soil water loss as compared to current natural vegetation. Alamo switchgrass can attain high and stable yield in the southern US without significant influence on soil water quantity.