Past, Present, and Future of Irrigation on the U.S. Great Plains

Abstract

Highlights Irrigation is key to the productivity of Great Plains agriculture but is threatened by water scarcity. The irrigated area grew to >9 million ha since 1870, mostly since 1950, but is likely to decline. Changes in climate, water availability, irrigated area, and policy will affect productivity. Adaptation and innovation, hallmarks of Great Plains populations, will ensure future success. Abstract. Motivated by the need for sustainable water management and technology for next-generation crop production, the future of irrigation on the U.S. Great Plains was examined through the lenses of past changes in water supply, historical changes in irrigated area, and innovations in irrigation technology, management, and agronomy. We analyzed the history of irrigated agriculture through the 1900s to the present day. We focused particularly on the efficiency and water productivity of irrigation systems (application efficiency, crop water productivity, and irrigation water use productivity) as a connection between water resource management and agricultural production. Technology innovations have greatly increased the efficiency of water application, the productivity of water use, and the agricultural productivity of the Great Plains. We also examined the changes in water stored in the High Plains aquifer, which is the region’s principle supply for irrigation water. Relative to other states, the aquifer has been less impacted in Nebraska, despite large increases in irrigated area. Greatly increased irrigation efficiency has played a role in this, but so have regulations and the recharge to the aquifer from the Nebraska Sand Hills and from rivers crossing the state. The outlook for irrigation is less positive in western Kansas, eastern Colorado, and the Oklahoma and Texas Panhandles. The aquifer in these regions is recharged at rates much less than current pumping, and the aquifer is declining as a result. Improvements in irrigation technology and management plus changes in crops grown have made irrigation ever more efficient and allowed irrigation to continue. There is good reason to expect that future research and development efforts by federal and state researchers, extension specialists, and industry, often in concert, will continue to improve the efficiency and productivity of irrigated agriculture. Public policy changes will also play a role in regulating consumption and motivating on-farm efficiency improvements. Water supplies, while finite, will be stretched much further than projected by some who look only at past rates of consumption. Thus, irrigation will continue to be important economically for an extended period. Sustaining irrigation is crucial to sustained productivity of the Great Plains “bread basket” because on average irrigation doubles the efficiency with which water is turned into crop yields compared with what can be attained in this region with precipitation alone. Lessons learned from the Great Plains are relevant to irrigation in semi-arid and subhumid areas worldwide. Keywords: Center pivot, Crop water productivity, History, Sprinkler irrigation, Subsurface drip irrigation, Water use efficiency.

A 2020 Vision of Subsurface Drip Irrigation in the U.S.

“…The status of SDI at the beginning of the last decade within the entire U.S. was summarized by Lamm et al (2012a), who also reported the opportunities and challenges that exist for SDI adoption. The past, present, and future of irrigation in the Great Plains were discussed by Evett et al (2020b), who noted the growing interest and use of SDI and other advanced irrigation technologies and their importance in the future.…”

Daily soil temperature modeling improved by integrating observed snow cover and estimated soil moisture in the U.S. Great Plains

“…Since precipitation gradients exist in the U.S. Great Plains from western to eastern regions (Evett et al, 2020), three subregions were classified for each state as western (100 o W towards west), central (between 97 o and 100 o W), and eastern ( 97 o W towards east). Figure 8 displays the time series of EM02 modeled, iEM02 modeled, and observed soil temperatures only covering winter wheat growing seasons (October 1 to June 30) for four growing seasons from 2015 to 2019 (validation periods) in Nebraska and Kansas.…”

“…A reliable estimate of soil temperature (Ts) is useful to understand agricultural ecological systems, hydrological processes, and land-atmosphere interactions (Lembrechts et al, 2020;Qi et al, 2016;Zhang et al, 2018) due to the fact that Ts governs physical, chemical, and biological processes of the soil and interactions between the atmosphere and land-surface (Smith, 2000;Soong et al, 2020). In particular, Ts has been widely used for a better understanding of changes in soil moisture (Lakshmi et al, 2003), the ecosystem carbon balance (Goulden et al, 1998), and the nitrogen mineralization process (Persson and Wirén, 1995) although a larger prevalence of air temperature observations are available as a soil temperature proxy. From a practical perspective, Ts is critical for agricultural system models such as the crop environmental resource synthesis (CERES) models to assess the impacts of extreme climate on crop production and stress tolerance, thereby allowing producers to better prepare for proactive and reactive field management (Bergjord et al, 2008;Persson et al, 2017;Williams et al, 1989).…”

Irrigation and Energy: Issues and Challenges

“…Corn, wheat, soybean and forages are cultivated over 55 million ha, producing 22% of the total crop value in the USA. About 8 million ha of this area is irrigated, the result of a rapid expansion which started in the 1950s with the invention of centre pivot irrigation systems, rural electrification, and improved well drilling and pump technologies (Evett et al, ). Initially, farmers thought that the Ogallala aquifer, the main water source, was unlimited; however, they soon found that, especially in the southern and western parts of the aquifer, their pumping exceeded the recharge so that the water table began to decline (Scanlon et al, ).…”