Groundwater, corn and cattle: an investigation on the implications of future groundwater availability on the agricultural industry in western Kansas

Abstract

Kansas relies on groundwater for nearly 85 percent of the total water used each year, most of which is used for irrigation. Over the last 30 years, declining groundwater levels in some areas have put pressure on agricultural industries. Ongoing research on the usage of groundwater resources will be necessary to sustain agriculture. In this study, two groundwater models were developed to investigate groundwater availability and use in western Kansas. The first model, called the Saturated Thickness Model (STM), investigated how groundwater resources will change over the next century. The second model, called the Change in Water Level Model (CWLM), was used to forecast water use trends for three agricultural districts in western Kansas by relating the change in groundwater levels over time to the volume of water pumped for irrigation. To understand how these changes would affect the agricultural industry, the research investigated historical trends in reported groundwater use, corn production and cattle in feedyards. The results showed significant decreases in the modeled saturated thickness over the next 100 years in western Kansas. Modeled groundwater use matched reported groundwater use data relatively well. The model showed significant decreases in groundwater use over the next 100 years, with the largest decrease being in the southwest district. Overall, forecast water use trends were in agreement with current outlooks for each area. The results from the correlation analysis showed a negative relationship between groundwater use and irrigated corn production, indicating improved irrigation efficiency and crop species over the past 30 years. Further correlations showed the number of cattle on feed in a particular area increased with the amount of irrigated corn production in the same area. This implies the cattle feedyards tendency toward local source of grain. As groundwater resources decline, corn production will decrease, and changes in the agricultural landscape will require adaptation. Feedyards will need to find new sources of corn grain or change to a less water dependent feed. Further research is needed to determine where corn grain will be produced in the next 100 years, and how corn grain will be transported to feedyards in southwest Kansas.