|MOUNCE, RYAN - West Texas A & M University|
|BLASER, BROCK - West Texas A & M University|
|Evett, Steven - Steve|
Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2016
Publication Date: 3/21/2016
Citation: Mounce, R.B., Oshaughnessy, S.A., Colaizzi, P.D., Blaser, B.C., Evett, S.R. 2016. Crop response of drought tolerant and conventional maize hybrids in a semi-arid environment. Irrigation Science. 34(3):231-244.
Interpretive Summary: Corn is an important crop for feeding livestock in the Central and Southern High Plains of Texas. Drought tolerant varieties of corn are now available to farmers. However, there is little information to determine if these new varieties use less water than common varieties and produce similar yields. ARS scientists at Bushland, Texas and scientists from West Texas A & M University used soil water measurements to determine the weekly amount of water to apply to common and drought tolerant varieties of corn that were grown side-by-side in the same center pivot field. The drought tolerant variety required less water during the two growing seasons and produced yields that were similar to the common variety when water was applied to met the full demands of the crop or were slightly less than optimal.
Technical Abstract: In the Central and Southern High Plains Regions, corn (Zea mays L.) is an important commodity for livestock feed. However, limited water resources and drought conditions can hinder corn production. Drought tolerant (DT) corn hybrids could help stabilize yields under water-limited conditions, though consistent response of such hybrids is unverified. In this two-year study (2013 and 2014), the effects of three irrigation treatments (levels of 100 percent, 75 percent, and 50 percent replenishment of soil water depletion to field capacity, I100, I75 and I50, respectively) were investigated for two corn hybrids, Pioneer AQUAMax P0876HR and Pioneer 33Y75, a DT and conventional hybrid, respectively. In 2013, the drier of the two years, crop water use (ETc) was significantly greater for the conventional hybrid, but grain water use efficiency (WUE) and harvest index (HI) were significantly greater for the DT hybrid. Cumulative irrigation amounts applied to the DT hybrid at the I100 and I75 treatments were 11 percent and 32 percentless, respectively, than the amount applied to the conventional hybrid at the I100 treatment, without significant reduction in grain yields. In 2014, grain yields and WUE were not significantly different between hybrids. However, ETc and biomass yields were greater for the conventional hybrid, while HI was greater for the DT hybrid. Again, cumulative irrigation amounts applied to the DT hybrid for the I100 and I75 treatments were 17 percent and 34 percent less, respectively, than the amount applied to the conventional hybrid at the I100 treatment. Harvest index was always greater for the DT hybrid when grouped by irrigation treatment. Results from both years indicate that the DT hybrid required less water to maximize grain yield as compared with the conventional hybrid. Irrigation amounts at 75 percent replenishment of soil water depletion to field capacity can result in relatively high yields in the DT hybrid using substantially less water than required for the conventional hybrid. Producing relatively high yields with reduced amounts of water may provide a means for producers to continue corn production in a semiarid environment with declining water supplies.