Water Use Efficiency of Different Maturity Corn Hybrids and Grain Sorghum in the Central Great Plains

Abstract

In areas of finite groundwater resources, the groundwater used for irrigation must be used as efficiently as possible. Yields and water use characteristics of longer‐maturity corn (Zea mays L.; 118‐d relative maturity), shorter‐maturity corn (97‐d relative maturity), and grain sorghum [Sorghum bicolor (L.) Moench] under full and limited irrigation were evaluated from 1993 to 1996. Mean yield of longer‐maturity corn was 15 bu/acre greater than that of shorter‐maturity corn and 50 bu/acre greater than that of grain sorghum. Longer‐maturity corn used the greatest amount of water, 3.4 in. greater than shorter‐maturity corn or grain sorghum. Average water use rates were similar among the three crops. Mean water use efficiency for longer‐maturity corn was not different from that of shorter‐maturity corn; mean water use efficiency of grain sorghum was 1.4 bu/acre per in. less. Mean yield of fully irrigated crops was 15 bu/acre greater than that for crops under limited irrigation (replacing 70% of crop evapotranspiration [ET]). Water use efficiency of crops under limited irrigation was 0.7 bu/acre per in. greater than under full irrigation, but full irrigation of corn was more profitable than limited irrigation. These yields, average water use rates, and water use efficiencies indicate no justification for choosing shorter‐over longer‐maturity corn. Research Question In the search to stretch finite water supplies, irrigators have looked to shorter‐maturity corn hybrids or grain sorghum in an attempt to pump less irrigation water in a given growing season, even though it may mean accepting decreased grain yield. This study compared the water use, average water use rate, water use efficiency, and yields of longer‐maturity corn, shorter‐maturity corn, and grain sorghum grown and irrigated at two levels (fully irrigated and 70% of fully irrigated). Literature Summary The comparison of water use characteristics of shorter‐ and longer‐maturity corn has been made recently. In the southern High Plains, the different maturity‐length hybrids were shown to have similar water use rates until the shorter‐maturity corn began to senesce later in the growing season. They also had similar water use efficiencies. In recent years, grain sorghum has been recommended over corn when total irrigation water applications would be less than about 8 in. However, corn has been shown in other research to be higher‐yielding and more profitable than grain sorghum in rotation with wheat. Study Description Longer‐maturity corn (Pioneer hybrid 3162), shorter‐maturity corn (Pioneer hybrid 3751), and grain sorghum (DeKalb DK‐56) were grown and irrigated on Ulysses silt loam. Treatments were (i) three crops (longer‐maturity corn, shorter‐maturity corn, and grain sorghum); (ii) two planting dates (early and late); and (iii) two irrigation amounts (full, or 100% replacement of estimated evapotranspiration [ET], and limited, or 70% replacement of estimated ET). Conventional production practices (tillage, fertility, weed control) for the area were used. The plo...

Cumulative deficit irrigation effects on corn biomass and grain yield under two tillage systems

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Leaf Transpiration Efficiency of Some Drought‐Resistant Maize Lines

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Physiological response, molecular analysis and water use efficiency of maize (Zea mays L.) hybrids grown under various irrigation regimes

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