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EFFECT OF TIMING AND AMOUNT OF IRRIGATION AND DROUGHT STRESS CONDITIONING IN CORN (ZEA MAYS L.)
Abstract
Corn is widely grown under irrigation in Nebraska. Water availability may become a limiting factor to corn production. A research project was initiated to identify the optimum irrigation timing dependency on the amount of water available for irrigation. A closely related objective was to investigate the existence, nature and possible utilization of a drought stress conditioning mechanism in corn. The experiment was carried out in 1976 through 1978 at the Sandhills Agricultural Laboratory of the University of Nebraska located in west-central Nebraska. A double line source gradient irrigation was used to study the effect of different intensities of drought stress at one particular growth stage or the interaction of drought stress at two or more growth stages. The optimum irrigation timing to obtain maximum yield per unit of water used depended on the amount of water available for irrigation. They are described in order of decreasing water availability. When water was only partially limited the largest water use efficiency was obtained by applying limited or no irrigation during the vegetative period and full irrigation thereafter. As water supplies decreased the best efficiency was obtained by withholding irrigation during the vegetative period, applying full irrigation during the pollination period and limited irrigation during the grain filling period. When only a small amount of water is available for irrigation, the greatest efficiency was obtained by withholding irrigation during the vegetative period and applying limited irrigation during the pollination period. Some grain was produced in all cases with no irrigation after the four leaf stage. It was found that greater water use efficiency was obtained when water was not severely limited by using high plant density ((DBLTURN) 75,000 plants/ha). However, when water was severely limited, greater water use efficiency was obtained by using lower plant density (30,000 to 35,000 plants/ha). The adequate density under limited water availability is dependent on year and location. Maximum leaf area per plant remained constant with increasing plant density. Maximum leaf area index increased linearly with increasing plant density. Grain yield was linearly related to maximum leaf area index. When corn was subject to drought stress during the grain filling period grain yield was linearly related to leaf area duration after blister stage. Leaf area duration after blister stage was in turn linearly related to evapotranspiration that occurred during the grain filling period. Corn subject to drought stress during the pollination period had a greater water use efficiency when it had been subjected to drought stress during the vegetative period (conditioning treatment) than when it had been adequately watered during the vegetative period (non-conditioned). Likewise, corn subjected to drought stress during the grain filling period had a greater water use efficiency when it had been subjected to drought stress prior to blister stage (conditioning treatment) than when it had been adequately irrigated prior to blister stage (non-conditioned). It is concluded that greater water use efficiency of corn subject to a conditioning period of stress is due to reduced water use during the conditioning period and not to any physiological "drought stress conditioning" response per se. It was concluded that no conditioning effect was present for two main reasons. First, ear production per plant was equally sensitive to water deficits during the pollination period regardless of previous stress history. Second, the same amount of grain was produced per unit of evapotranspiration regardless of previous stress history.
Subject Area
Agronomy
Recommended Citation
MAURER ORTIZ MONASTERIO, ROBERTO EUGENIO, "EFFECT OF TIMING AND AMOUNT OF IRRIGATION AND DROUGHT STRESS CONDITIONING IN CORN (ZEA MAYS L.)" (1981). ETD collection for University of Nebraska-Lincoln. AAI8118173.
https://digitalcommons.unl.edu/dissertations/AAI8118173