Response of maize hybrids under limited irrigation capacities: Crop water use

Authors: Schwartz, Robert; BELL, JOURDAN - Texas A&M Agrilife; Colaizzi, Paul; Baumhardt, Roland - Louis; Hiltbrunner, Bridgette

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2022
Publication Date: 1/31/2022
Citation: Schwartz, R.C., Bell, J.M., Colaizzi, P.D., Baumhardt, R.L., Hiltbrunner, B.A. 2022. Response of maize hybrids under limited irrigation capacities: Crop water use. Agronomy Journal. 114:1324-1337. https://doi.org/10.1002/agj2.21011.
DOI: https://doi.org/10.1002/agj2.21011

Interpretive Summary: Producers often experience sizable yield losses in corn because irrigation cannot meet demand. This has become a common occurrence in the semiarid Texas High Plains where irrigation supply from the Ogallala Aquifer is in decline. Drought tolerant corn hybrids may reduce yield losses during periods of water stress by using soil water so that it is more available during sensitive growth periods. Scientists from ARS (Bushland, Texas) and Texas A&M AgriLife studied the effect of irrigation level and planting rate on soil water use by three maize hybrids, two of which were considered drought tolerant. Water use by the maize crop was greatest under deficit irrigation. Only 4% of the seasonal water use of the crop was extracted below a soil depth of 2.6 feet. Plant density did not significantly influence crop water use. Water use during the growing season did not differ among hybrids. Drought tolerant traits may have a diminished effect on water use by maize because of high evaporative demands at this location.

Technical Abstract: Maize (Zea Mays L.) production in the semiarid Texas High Plains often suffers exceptional yield reductions when irrigation cannot meet seasonal and peak water requirements. Drought tolerant hybrids may reduce yield losses resulting from water stress by altering seasonal soil water use patterns to permit greater uptake during yield sensitive growth stages. We examined the effect of irrigation flow capacity (8.47 and 4.23 mm d-1) and planting rates (74,000 and 95,000 seeds ha-1) during three growing seasons (2016 – 2018) on water use of three maize hybrids, two of which were considered drought tolerant. Changes in stored soil water were examined for the entire profile and for segregated depth increments (0–0.4, 0.4–0.8, and 0.8–1.4 m). Seasonal crop evapotranspiration averaged 754 and 592 mm across years for the high and low irrigation levels, respectively. Irrigation level significantly affected seasonal change in stored soil water in one year (2018) with greater depletion at harvest under the low irrigation level. Profile soil water use at 0.8–1.4 m comprised less than 4% of seasonal water use. Plant density did not significantly influence crop water use. Hybrids did not differ with respect to growing season crop water use. Stored soil water throughout the growing season within the examined depth increments were similar among hybrids, with significant differences occurring infrequently and inconsistent across years. Drought tolerant traits may have a diminished effect on transpiration due to the dense clay loam soil or the high atmospheric demand at the study location.