Effects of Nitrogen Rate, Irrigation Rate, and Plant Population on Corn Yield and Water Use Efficiency

crucial for the survival of agriculture in northeastern Colorado. Improper N and irrigation management are major factors contribThe relationships of corn yield and nitrate leaching uting to water quality and shortage problems in the Great Plains. with irrigation, N fertilization, and plant population This study was conducted on the Irrigation Research Farm in Yuma, have been extensively investigated. Irrigation effectively CO, from 1998 through 2000 to establish an accurate irrigation and N management system for corn (Zea mays L.) production in the increases corn yield although WUE expressed as corn Great Plains aimed at high yield and water use efficiency (WUE) yield to total water use ratio decreases as irrigation rate simultaneously. A field experiment was conducted on a center-pivot– increases (Stone et al., 1987, 1993; Hergert et al., 1993). irrigated, well-drained Haxtun sandy loam soil (fine-loamy, mixed, Nitrogen fertilization also increases corn yield when N superactive, mesic Pachic Argiustolls) by using a randomized complete supply by soil is low (Wienhold et al., 1995; Sexton et al., block split-split plot design, with irrigation rates [0.60, 0.80, and 1.0