Carbon Cycling from Biofuel Crop Production in the Mid-Continental U. S. Region Predicted from MODIS Satellite Data and Ecosystem Modeling

The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate biomass production from croplands across the states of Iowa and Nebraska (United States) over the period 2001-2004. Adjustments for light-use efficiency and water use in biofuel (both corn and perennial grass) crops were carried out across the region, resulting in a new mapping of aboveground and belowground carbon pools based on 500-meter resolution MODIS satellite data. Simulations of plant residue management and soil carbon decomposition were conducted in the NASA-CASA model during and following conversions to biofuel crops to track the fate of carbon pools and the emissions of greenhouse gases. Initial results are being compared to biofuel production reports from southern Iowa for model calibration and validation. The long-term aims of this research are to enhance understanding of the effects of biofuel feedstocks on the biogeochemical cycling of carbon, nitrogen, and water by bringing NASA satellite data sets to bear on the problems of tracking cropland production trends and shifts in different cover areas of native vegetation and biofuel crops.