Location: Soil and Water Management ResearchTitle: Transitioning agricultural production for a declining aquifer in a semi-arid region
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2019
Publication Date: 11/11/2019
Citation: Baumhardt, R.L., Schwartz, R.C., Mauget, S.A. 2019. Transitioning agricultural production for a declining aquifer in a semi-arid region [abstract]. 2019 ASA-SSSA-CSSA Annual International Meeting, November 11-13, 2019, San Antonio, Texas. Abstract No. 85-4.
Technical Abstract: Water pumped from the High Plains Aquifer for irrigation, generally dwarfs groundwater recharge in the western Great Plains south of Nebraska; thus, making current irrigated crop production unsustainable. Abandoning irrigation for dryland production is not uncommon and may be a first step towards realizing Deborah and Frank Popper’s 1987 predicted Great Plains depopulation and introduction of Buffalo to become the “Buffalo Commons”. Irrigation has been made more efficient for potentially extending Aquifer longevity using innovative application technologies and more accurate estimates of crop water demand. Nevertheless, irrigated production must transition from fully meeting crop water demand to some deficit irrigation while remaining economically viable and converging to a suitably productive dryland cropping paradigm of equally innovative management strategies. Combined field experiments and crop growth simulation at the USDA-ARS Conservation and Production Research Laboratory in Bushland, TX, have identified alternative irrigation management strategies. The declining irrigation capacity for a fixed area of, for example, a pivot irrigation system decreases overall crop water use efficiency (WUE); however, partial pivot irrigation at higher than uniform application capacities increases overall production and WUE by combining dryland and irrigated production. Where the goal is to optimize deficit irrigated crop production with increased reliance on precipitation, climate informed management using El Niño Southern Oscillation (ENSO) phase may guide land and livestock management decisions. For instance, long-term (1954 to 2011) grain yield of wheat (Triticum aestivum L.) was increased during predictable El Niño compared with La Niña climate phases. The corresponding measured long-term sorghum [Sorghum bicolor (L.) Moench] grain yield did not vary significantly (P>0.10) with ENSO phase, but simulated yields for fixed cropping conditions were reduced during the drier La Nina phase years. Successful intensification of the dryland wheat-sorghum-fallow rotation by adding grazed stocker cattle modestly improved productivity but was less than ungrazed no-till management. Improved WUE through innovative irrigation management strategies and application technologies will extend the useful longevity of the High Plains Aquifer.