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WATER USE AND IRRIGATION RESPONSE TO DEFOLIATED CORN WITH VARIOUS POPULATIONS (IRRIGATION SCHEDULING)
Abstract
Field experiments designed to simulate hail damage at various developmental stages revealed an unexpected and potentially important response from corn (Zea mays L.). Of particular interest were yields following the 50% tasseling stage. The objective of the study was to determine the influence of water gradient level, population, and defoliation on the yield, growth, and water use efficiency of corn. Experiments were laid out in a split randomized block arrangement at Rogers' Farm, University of Nebraska-Lincoln, Lincoln, Nebraska in 1981, 1982, and 1983 with six main plots as nonrandomized water gradients, four subplots as 25,000-70,000 plants per hectare (pph), and two sub-subplots as two defoliation treatments by using line source sprinkler irrigation system (Hanks, et al., 1976). Yields increased linearly as the water level increased from 20-80%. Magnitudes of difference among water levels were greater in 1983, a severe stress season. Water gradient and plant population interaction occurred, which is further evidence that 1983 was very dry. Under irrigation 55-70,000 pph performed better, whereas under limited irrigation 40,000 pph outyielded other populations. Defoliated corn yielded 9% more than nondefoliated corn and the yields of defoliated corn were greatly influenced by water but not population in the same year. However, nondefoliated corn showed a 20-30% increase in 1981 and 1982. Total dry matter and total ear weight both increased as time and water gradient level increased, particularly from the 20-80% water gradients. A linear relationship was found between evapotranspiration (ET) and yield, with the steepest slope obtained in 1983. Systematic reduction in water use efficiency (WUE) was observed with decrease in quantity of water applied. Neither plant populations nor defoliation treatments influenced evapotranspiration (ET). However, higher WUE was observed with defoliated corn only in 1983. ET influenced total dry matter, ear weight, and dry grain weight progressively as reproductive growth advanced. A linear model was the best to describe the relationship between ET and these variables at physiological maturity.
Subject Area
Agronomy
Recommended Citation
RAO, KONDAPANENI GOPAL, "WATER USE AND IRRIGATION RESPONSE TO DEFOLIATED CORN WITH VARIOUS POPULATIONS (IRRIGATION SCHEDULING)" (1986). ETD collection for University of Nebraska-Lincoln. AAI8706243.
https://digitalcommons.unl.edu/dissertations/AAI8706243