Date of this Version
Proceedings of the Great Plains Soil Fertility Conference, Denver, Colorado, March 5-6, 2002, ed. Alan J. Schlegel.
Dryland corn (Zea mays L.) hectarage increased more than seven-fold from 1995 through 1999 in semiarid western Nebraska. Corn management recommendations are lacking for this area. The objectives of this study were to determine proper management practices for dryland corn relative to plant population and N fertility. In 1999 and 2000, experiments were conducted each year at four sites in western Nebraska. Experimental treatments were plant populations (17 300, 27 200, 37 100, 46 900, and 56 800 plants ha-1) and N fertilizer rates (0, 34, 67, 101, and 134 kg N ha-1) arranged in a randomized complete block with five replicate blocks. Corn grain yield varied from 300 kg ha-1 to 5620 kg ha-1. Optimal plant populations ranged from 17 300 to more than 56 800 plants ha-1. To achieve maximum yield, total N supply from soil and fertilizer of 188 kg N ha-1 was necessary. To optimize yield (95% of maximum) a total N supply of 125 kg N ha-1 was needed. The amount of N supply required for optimal corn yields was not related to the yields obtained, and so fertilizer N needs of the crop can be estimated based on preplant soil samples.