Irrigation management effects on crop water productivity for maize production in the Texas High Plains

Authors: Marek, Gary; MAREK, THOMAS - Texas A&M Agrilife; Evett, Steven - Steve; CHEN, YONG - Texas A&M University; HEFLIN, KEVIN - Texas A&M Agrilife; Moorhead, Jerry; Brauer, David

Submitted to: Water Conservation Science and Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2020
Publication Date: 1/13/2021
Citation: Marek, G.W., Marek, T.H., Evett, S.R., Chen, Y., Heflin, K., Moorhead, J.E., Brauer, D.K. 2021. Irrigation management effects on crop water productivity for maize production in the Texas High Plains. Water Conservation Science and Engineering. 6:37-43. https://doi.org/10.1007/s41101-020-00100-x.
DOI: https://doi.org/10.1007/s41101-020-00100-x

Interpretive Summary: Corn production in much of the southern Great Plains relies on irrigation form the Ogallala Aquifer to supplement inadequate precipitation. Decades of pumping with minimal recharge has resulted in declining water tables and reduced well capacities in much of the region. Prudent irrigation scheduling remains an effective tool for maximizing crop water productivity, particularly under deficit irrigation. Although many studies have addressed the effects of irrigation timing and duration of water deficit on corn growth and yield, few have studied the effects of irrigation depth and frequency under similar conditions in the same growing season. Researchers from the USDA-ARS Bushland and Texas A&M AgriLife Research Amarillo compared yield and crop water productivity values from high frequency, low irrigation and low frequency, high irrigation management in two fields. Results indicated there was no obvious reduction in evaporative losses associated with the less frequent, greater application as full canopy conditions limited excessive evaporation.

Technical Abstract: Corn (Zea mays L) was grown under full and deficit irrigation regimes in two sets of research fields located at the USDA-ARS Conservation and Production Research Laboratory (CPRL) near Bushland, TX in 2018. Irrigation was scheduled to allow no more than 55 percent depletion of plant available soil water for the fully irrigated treatments in both fields. However, irrigation depth and frequency were different in each field. One set of fields (lysimeter fields) was irrigated twice weekly using irrigation depths ranging from approximately 19 to 32 mm. The other set of fields (Emeny fields) was irrigated less often, typically once per week, but having greater application depths ranging from 35 to 42 mm. Deficit irrigation treatments of 75 percent of full irrigation were also performed in both research fields with an additional 50 percent treatment in the Emeny fields. Seasonal water use values and combine harvest data were used to compute crop water productivity (CWP) values for all treatments in both fields. Results indicated there was no obvious reduction in evaporative losses associated with the less frequent, greater application on the Emeny field. Both the yields of 12,288 and 11,471 kg/ha and the CWP values of 1.74 and 1.78 for the 100 and 75 percent lysimeter field irrigation treatments, respectively, were greater than corresponding values for the Emeny field. Yields from the Emeny fields may have been slightly reduced by heat stress incurred between irrigations during the early grain fill period whereas the more frequent irrigations on the lysimeter fields may have reduced heat stress during that period.