In the 2007 year, CGRER awarded five seed grants totaling $148,230.

Optimization of Environmental and Economic Benefits of Corn Harvesting for Biofuel Production Amy Kaleita

Biofuels are seen as economic windfalls for Iowa. While corn-based biofuels currently are made from the corn kernels, methods for converting lignin-containing plant materials (such as corn stalks and leaves) into ethanol are being developed. However, the removal of corn residues from cropland significantly increases the risk of soil erosion — one of several potential environmental costs related to biofuel production. How do biofuel’s immediate economic benefits balance with such long-term environmental costs and the land’s sustainability? Amy Kaleita and James Newman created a numerical model that produced a county-by-county “erosion risk map” that estimates soil loss at different rates of corn residue harvest. This model is available to individual farmers, who can use it to calculate biofuel-related erosion losses on a more detailed level.

The Effect of Harvesting Trees, Shrubs, and Native Grasses on Soil Carbon Sequestration and Greenhouse Gas Flux in Riparian Buffers Designed to Provide Biomass for Biofuel Production

Riparian buffer strip plantings concentrate nitrogen fertilizers and carbon in their living and dead plant parts. Because they sequester more carbon and nitrogen than they release, buffers help control the greenhouse gases carbon dioxide, nitrous oxide, and methane. By supplying carbon to the microbes in the soil ecosystem, riparian buffers stimulate the denitrification process which converts excess nitrogen fertilizer to harmless nitrogen gas. Buffer strip plants are now being considered as a cellulosic biofuel feedstock. This use would increase the frequency of harvesting and accelerate decomposition in the buffers. Such changes may shift the release of harmless nitrogen gases to higher proportions of potent nitrous oxide. Richard Schultz and Thomas Isenhart compared the release of the various forms of nitrogen gas (as well as carbon dioxide and methane) from undisturbed riparian buffer strips with that of harvested sites, and thus assessed the ramifications of biofuel production before such harvests commence.

Inter-Calibration of Global Remotely Sensed Vegetation Measures

Numerical models of vegetation, hydrology, climate and other environmental processes rely in part on data collected by satellites. Data sets of nearly 30 years duration are available, but recent design advances have improved sensors that collect information on the spectral and thermal characteristics of Earth’s surface. Although previous data sets continue to provide valuable long-term records, improving the compatibility of earlier data sets and more recent data collected with the improved sensors would provide more robust analysis of the Earth’s surface features. Marc Linderman, Kate Cowles, and Dale Zimmerman provided such improved compatibility by using current, high-quality satellite data to correct earlier, less reliable data sets. The improved data sets better assess trends in our planet’s vegetational activity, and provide better baseline information for today’s more precise studies of changes in agriculture, land cover, and climate.

Heterogeneous Photochemistry of Atmospheric Aerosol

For nearly a decade, Vicki Grassian and collaborators have been working with heterogeneous atmospheric chemistry — that is, the chemical interplay between atmospheric particles and trace atmospheric gases. She has investigated how these interactions are significant in altering the troposphere’s chemical balances, a feature important to the modeling of changing climate. She and Mark Young extended that research into a new area, incorporating the effects of sunlight and asking the question, “What influence does heterogeneous photochemistry play in atmospheric chemistry?” They looked at organic material of biological origin (e.g. from soil) as well as organic- and nitrate-coated particles, and measured light-induced changes in the particles and key trace gas species, changes that also could be important to climate and climate models.

Observational and Modeling Studies of Rainfall Interception by Corn Plants

Numerical models are continuing to increase our scientific understanding of the hydrological cycle. However, variations in the Earth’s surface cover and other variables continue to confound measurements and models. Witold Krajewskiaddressed one such variable: interception of rainfall by corn, a process that is not well understood. Corn provides significant storage for water when integrated over Iowa’s vast fields of rowcrops. This storage modifies rainfall-runoff processes and the exchange of water mass and energy between land surface processes and the atmosphere through evaporation. The project studied the interception of rainfall by corn plants using in-house developed sensor systems. The grant funded the development of the observational system and demonstrated its usefulness in the field — efforts that are necessary prerequisites to subsequent field-sampling experiments and the development of mathematical models of the rainfall interception process.