Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 20, 3325-3342, 2016
https://doi.org/10.5194/hess-20-3325-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Aug 2016
Assessment of impacts of agricultural and climate change scenarios on watershed water quantity and quality, and crop production
Awoke D. Teshager1, Philip W. Gassman2, Justin T. Schoof3, and Silvia Secchi3 1Graham Sustainability institute, University of Michigan, 214 S State St., Suite 200, Ann Arbor, MI 48104, USA
2Department of Economics, Center for Agricultural and Rural Development, Iowa State University, 560A Heady Hall, Ames, IA 50011, USA
3Geography and Environmental Resources, Southern Illinois University Carbondale; Faner Hall, Carbondale, IL 62901, USA
Abstract. Modeling impacts of agricultural scenarios and climate change on surface water quantity and quality provides useful information for planning effective water, environmental and land use policies. Despite the significant impacts of agriculture on water quantity and quality, limited literature exists that describes the combined impacts of agricultural land use change and climate change on future bioenergy crop yields and watershed hydrology. In this study, the soil and water assessment tool (SWAT) eco-hydrological model was used to model the combined impacts of five agricultural land use change scenarios and three downscaled climate pathways (representative concentration pathways, RCPs) that were created from an ensemble of eight atmosphere–ocean general circulation models (AOGCMs). These scenarios were implemented in a well-calibrated SWAT model for the intensively farmed and tiled Raccoon River watershed (RRW) located in western Iowa. The scenarios were executed for the historical baseline, early century, mid-century and late century periods. The results indicate that historical and more corn intensive agricultural scenarios with higher CO2 emissions consistently result in more water in the streams and greater water quality problems, especially late in the 21st century. Planting more switchgrass, on the other hand, results in less water in the streams and water quality improvements relative to the baseline. For all given agricultural landscapes simulated, all flow, sediment and nutrient outputs increase from early-to-late century periods for the RCP4.5 and RCP8.5 climate scenarios. We also find that corn and switchgrass yields are negatively impacted under RCP4.5 and RCP8.5 scenarios in the mid- and late 21st century.

Citation: Teshager, A. D., Gassman, P. W., Schoof, J. T., and Secchi, S.: Assessment of impacts of agricultural and climate change scenarios on watershed water quantity and quality, and crop production, Hydrol. Earth Syst. Sci., 20, 3325-3342, https://doi.org/10.5194/hess-20-3325-2016, 2016.
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Short summary
Current water quality problems due to intensification of corn in agricultural watersheds is expected to be exacerbated by the projected change in climate further in the 21st century. Therefore, there is an urgent need to develop alternative biofuel cropping systems and/or implement effective management practices to counteract future water quality problems that could develop from relying on extensive production of row crops in Corn Belt region watersheds.
Current water quality problems due to intensification of corn in agricultural watersheds is...
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