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Fluid Journal : Fluid Journal 1993-1995
Drs. P. R. Thomison, J. W. Johnson and D. J. Eckert NR NR NR NR N Rate, Hybrid and Plant P ate, Hybrid and Plant P ate, Hybrid and Plant P ate, Hybrid and Plant P ate, Hybrid and Plant Popu lation opulation opulation opulation opulation Affect Corn Y Affect Corn Y Affect Corn Y Affect Corn Y Affect Corn Yield ield ield ield ield Studies conducted over three-year span in eight different environments. Summary: Experiments were conducted in eight Ohio environments. Objective was to determine relationships between nitrogen (N) fertility and corn hybrids exhibiting different levels of ear adjustment (in ear determinancy and prolificacy) at varying plant populations. Grain yields were strongly influenced by N rate and plant population in most environments. Hybrid effects were significant in four of the eight environments and usually most evident under favorable growing conditions. Significant interactions involving hybrid, N, and population, occurred at only one of the eight locations. Response to N fertility and plant population was optimized under favorable growing conditions. Under drought stress, population and N fertility effects were much less pronounced or not significant. Response to N fertility and plant population for yield among the three hybrids was similar despite marked differences in hybrid ear types. For ears per plant, there were signficant interactions between hybrid, N, and plant density, with N strongly influencing prolificacy. Al- though the prolific hybrid showed a positive yield response to higher plant population, the increased lodging associ- ated with greater plant density would warrant planting this hybrid at suboptimal plant populations in certain environments. Experiments were conducted at the Ohio Agricultural Research and Development Center branches at Hoytville and South Charleston, Ohio. Objectives were I) to determine the effects on corn yields of interactions between nitrogen fertility, plant population, and hybrid, and 2) to determine the most cost-effective rates of N for different hybrids at varying plant density. The eight environments in which the experiments were conducted allowed sampling of different soil types and weather conditions and are representative of the variation in growing conditions in the major corn producing regions of Ohio. 75 150 225 180 170 160 150 140 130 120 110 Yield (bu/A) 16,000 plants/A 24,000 plants/A 32,000 plants/A N Rate - lbs/A Figure 1. Nitrogen fertility and plant population effects on corn yield using a Beck's 72X hybrid on a Kokomo silty clay loam. South Charleston, Ohio, 1993. 75 150 225 190 180 170 160 150 140 130 120 110 Yield (bu/A) N Rate - lbs/A Figure 2. Nitrogen fertility and plant population effects on corn yield using a Pioneer 3379 hybrid on a Kokomo silty clay loam. South Charleston, Ohio, 1993. 16,000 plants/A 24,000 plants/A 32,000 plants/A Yields boosted Grain yields were significantly affected by N rate, hybrid and plant population as shown in Figures 1, 2 and 3. The figures depict the results on a Kokomo silty clay loam in one of the eight environments (South Charleston) in 1993. Overall, there were significant differ- ences in yield among hybrids at four of the eight environments. The fixed ear hybrid P3379 exhibited consistently higher yields--- averaged across N rates and populations---than the prolific hybrid B72X in the three 1993 experiments. At South Spring 1994
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