State Water Resources Research Institute Program
Project ID: 2012IL250B
Title: The Impacts of Cellulosic Biofuel Feedstock Production on Midwest US Hydrologic Cycle
Project Type: Research
Start Date: 3/01/2012
End Date: 2/29/2013
Congressional District: 15
Focus Categories: Agriculture, Water Use, Nitrate Contamination
Keywords: Land-use-change, water use efficiency, evapotranspiration, streamflow, Gulf of Mexico Hypoxic Zone
Principal Investigators: Bernacchi, Carl; Bernacchi, Carl
Federal Funds: $ 31,814
Non-Federal Matching Funds: $ 148,394
Abstract: A significant portion of the Illinois and Midwest agricultural landscape is expected to undergo large-scale changes to accommodate bioenergy feedstocks. Approximately 40% of corn grain is currently used in ethanol production and it is unlikely that corn grain ethanol will rise beyond current production levels. Future liquid fuel production will require dedicated bioenergy feedstocks to provide cellulosic-based liquid energy. Illinois, along with other agriculturally rich areas of the Midwest, has been proposed as a region capable of producing a significant portion of the biomass required for cellulosic ethanol refineries. Highly productive perennial grasses such as Miscanthus x. giganteus (miscanthus) and Panicum virgatum (switchgrass) have been proposed as ideal feedstocks for cellulosic ethanol production based on rapid growth and high biomass measured at number of experimental sites throughout Illinois. Productivity is an important criterion by which to evaluate the potential of these feedstocks, but it is crucial to also understand the environmental impacts of a large scale shift in land use before it is implemented. This research will identify and quantify the potential environmental impacts of largescale cellulosic feedstock production on the hydrologic cycle of Illinois focusing both on water quantity (amount of water evapotranspired by crops, impacts on streamflow) and water quality (nitrate leaching from agricultural fields). We will focus on comparing the existing maize production system to the proposed cellulosic ecosystems using miscanthus and switchgrass as the primary feedstocks using a dynamic vegetation model, Agro-IBIS. This research will consist of two stages 1) model development and testing, and 2) model implementation and dissemination of results. Stage one has been executed, and involved the compilation of various datasets to parameterize and validate miscanthus and switchgrass algorithms into an existing dynamic vegetation growth model (Agro-IBIS; Integrated Biosphere Simulator - Agricultural version) ecosystem model.
This research will address three main objectives: 1) Assess the water use relative to the carbon gain (i.e. water use efficiency) of various feedstock production scenarios; 2) simulate impacts of various production scenarios on streamflow and the export of leached nitrogen from fertilizer; and 3) Identify the potential for climate feedbacks (e.g. surface temperature cooling or precipitation) under the various production scenarios. This research will be scaled from the plotscale through coupled measurements and modeling to the scale of the Midwest to determine how varying levels of production and nutrient application for maize, switchgrass, and miscanthus impact the Mississippi River Basin.
We predict that perennial feedstocks (miscanthus and switchgrass) will slightly decrease water use (objective 1) while, based on coupled simulations between Agro-IBIS and a terrestrial hydrology model, large reductions in nutrient application will greatly decrease the flux of nitrogen to the Gulf of Mexico 'Hypoxic Zone' (objective 2). Agro-IBIS will also be coupled with the WRF (Weather Research and Forecasting) atmospheric model to determine how changes in water use by the biofuel feedstocks could result in feedbacks on local and regional climate (objective 3). We predict that increased water use will increase the humidity of the lower troposphere, resulting in greater potential for precipitation, however coincident cooling due to greater evapotranspiration (ET) will decrease local convective precipitation.
The proposed project will add significant understanding to important hydrologic issues facing Illinois and the Midwest as a whole in coming decades. The results will help to inform policy decisions regarding issues associated with land-use-change and will demonstrate the importance of agroecosystems not only for food, fuel and fiber but also in providing ecosystem services such as regulating climate and providing clean water.