Physical Sciences and Mathematics Commons^™

Assessing The Potential To Decrease The Gulf Of Mexico Hypoxic Zone With Midwest Us Perennial Cellulosic Feedstock Production, Andy Vanloocke, Tracy E. Twine, Christopher J. Kucharik, Carl J. Bernacchi

Andy VanLoocke

The goal of this research was to determine the changes in streamflow, dissolved inorganic nitrogen (DIN) leaching and export to the Gulf of Mexico associated with a range of large-scale dedicated perennial cellulosic bioenergy production scenarios within in the Mississippi–Atchafalaya River Basin (MARB). To achieve this goal, we used Agro-IBIS, a vegetation model capable of simulating the biogeochemistry of row crops, miscanthus and switchgrass, coupled with THMB, a hydrology model capable of simulating streamflow and DIN export. Simulations were conducted at varying fertilizer application rates (0–200 kg N ha -1) and fractional replacement (5–25%) of current row crops with miscanthus …

Expression Of Cyanobacterial Fbp/Sbpase In Soybean Prevents Yield Depression Under Future Climate Conditions, Iris H. Kohler, Ursula M. Ruiz-Vera, Andy Vanloocke, Michell L. Thomey, Tom Clemente, Stephen P. Long, Donald R. Ort, Carl J. Bernacchi

Andy VanLoocke

Predictions suggest that current crop production needs to double by 2050 to meet global food and energy demands. Based on theory and experimental studies, overexpression of the photosynthetic enzyme sedoheptulose-1,7-bisphosphatase (SBPase) is expected to enhance C3 crop photosynthesis and yields. Here we test how expression of the cyanobacterial, bifunctional fructose-1,6/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) affects carbon assimilation and seed yield (SY) in a major crop (soybean, Glycine max). For three growing seasons, wild-type (WT) and FBP/SBPase-expressing (FS) plants were grown in the field under ambient (400 μmol mol−1) and elevated (600 μmol mol−1) CO2 concentrations [CO2] and under ambient and elevated temperatures (+2.7 …

A Realistic Meteorological Assessment Of Perennial Biofuel Crop Deployment: A Southern Great Plains Perspective, Melissa Wagner, Meng Wang, Gonzalo Miguez-Macho, Jesse Miller, Andy Vanloocke, Justin E. Bagley, Carl J. Bernacchi, Matei Georgescu

Andy VanLoocke

Utility of perennial bioenergy crops (e.g., switchgrass and miscanthus) offers unique opportunities to transition toward a more sustainable energy pathway due to their reduced carbon footprint, averted competition with food crops, and ability to grow on abandoned and degraded farmlands. Studies that have examined biogeophysical impacts of these crops noted a positive feedback between near-surface cooling and enhanced evapotranspiration (ET), but also potential unintended consequences of soil moisture and groundwater depletion. To better understand hydrometeorological effects of perennial bioenergy crop expansion, this study conducted high-resolution (2-km grid spacing) simulations with a state-of-the-art atmospheric model (Weather Research and Forecasting system) dynamically …

Impacts Of Second-Generation Biofuel Feedstock Production In The Central U.S. On The Hydrologic Cycle And Global Warming Mitigation Potential, K. J. Harding, T. E. Twine, Andy Vanloocke, J. E. Bagley, J. Hill

Andy VanLoocke

Biofuel feedstocks provide a renewable energy source that can reduce fossil fuel emissions; however, if produced on a large scale they can also impact local to regional water and carbon budgets. Simulation results for 2005–2014 from a regional weather model adapted to simulate the growth of two perennial grass biofuel feedstocks suggest that replacing at least half the current annual cropland with these grasses would increase water use efficiency and drive greater rainfall downwind of perturbed grid cells, but increased evapotranspiration (ET) might switch the Mississippi River basin from having a net warm-season surplus of water (precipitation minus ET) to …

Candidate Perennial Bioenergy Grasses Have A Higher Albedo Than Annual Row Crops, Jesse N. Miller, Andy Vanloocke, Nuria Gomez-Casanovas, Carl J. Bernacchi

Andy VanLoocke

The production of perennial cellulosic feedstocks for bioenergy presents the potential to diversify regional economies and the national energy supply, while also serving as climate ‘regulators’ due to a number of biogeochemical and biogeophysical differences relative to row crops. Numerous observational and model-based approaches have investigated biogeochemical trade-offs, such as increased carbon sequestration and increased water use, associated with growing cellulosic feedstocks. A less understood aspect is the biogeophysical changes associated with the difference in albedo (a), which could alter the local energy balance and cause local to regional cooling several times larger than that associated with offsetting carbon. Here, …

The Costs Of Photorespiration To Food Production Now And In The Future, Berkley J. Walker, Andy Vanloocke, Carl J. Bernacchi, Donald R. Ort

Andy VanLoocke

Photorespiration is essential for C3 plants but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco), reacts with oxygen instead of carbon dioxide and produces a toxic compound that is then recycled by photorespiration. Photorespiration can be modeled at the canopy and regional scales to determine its cost under current and future atmospheres. A regional-scale model reveals that photorespiration currently decreases US soybean and wheat yields by 36% and 20%, respectively, and a 5% decrease in the losses due to photorespiration would be worth approximately …

Miscanthus Establishment And Overwintering In The Midwest Usa: A Regional Modeling Study Of Crop Residue Management On Critical Minimum Soil Temperatures, Christopher J. Kucharik, Andy Vanloocke, John D. Lenters, Melissa M. Motew

Andy VanLoocke