Date of Award
Master of Science
Geological and Atmospheric Sciences
There are observed trends that show the climate is changing. Temperatures are rising, and precipitation patterns are shifting. In the central US, it is projected that there will be an increase in the frequency of spring precipitation, and a decrease in the summer. This precipitation shift can lead to an adverse affect on crop yield in farmed potholes, as this area is more susceptible to flooding or ponded conditions. A data gap exists on how crops respond to ponding within these farmed potholes, and if planting an alternative crop that is more resilient to drowning is a viable management change for these areas. We combined a range of future precipitation scenarios with an agroecosystem model to simulate the effects of contemporary (2002-2016) and future precipitation on a conventional corn/soybean (Zea mays L and Glycine max) rotation and an alternative perennial miscanthus (Miscanthus ÃÂÃÂ giganteus Greef et Deu) cropping system. The overall goal of this study was to develop a framework to assess the viability of planting the rhizomatous perennial grass miscanthus in farmed potholes under varying precipitation patterns and ponding conditions and improve the understanding of how traditional and alternative crops within farmed potholes react to a changing climate. In the context of this goal we hypothesized that 1) under the current climate, the control land use will have larger and more frequent losses in yield due to ponding relative to miscanthus, 2) under the future climate, depth and frequency of ponding will increase, but the dynamics of the ponding will be dependent on the way precipitation patterns change, and 3) under any future precipitation scenario, losses due to ponding will be greater in the conventional management of corn/soybean rotation relative to the perennials.
On average for the contemporary climate, 40.4% of corn/soybean yields were a total loss, and only 2.2% of the miscanthus yields were a total loss, supporting hypothesis 1. The corn/soybean rotation had more frequent total losses than miscanthus. The depth and frequency of ponding increased under most future precipitation scenarios, partially supporting hypothesis 2. Under two precipitation scenarios, the corn/soybean rotation and miscanthus simulations showed an increase in yield. For the two of the more extreme precipitation scenarios, the miscanthus had greater losses than the corn/soybean rotation. The corn/soybean rotation only experienced greater loss in yield than miscanthus for the most extreme scenario. While the relative losses were greater for some miscanthus scenarios, miscanthus did better in overall total production than corn and soybean. Our results show that compared to a conventional corn/soybean rotation, miscanthus performs better within farmed potholes under future precipitation scenarios. More data is required to further understand the economic viability and environmental benefits of transitioning conventionally farmed potholes to a perennial miscanthus alternative.
Patrick Michael Edmonds
Edmonds, Patrick Michael, "A Comparison of Conventional Annual and Alternative Perennial Cropping Systems Under Contemporary and Future Precipitation Scenarios in the US Prairie Pothole Region" (2017). Graduate Theses and Dissertations. 15298.