The Influence of Variations in Fertility Levels Upon the Yield and Protein Content of Field Corn in Eastern Oregon
1955
Hunter, Albert S. | Yungen, John A.
Thirteen fertilizer experiments with field corn were conducted on irrigated sierozemic soils of Malheur County, in extreme eastern Oregon, over a 3-year period, to determine the fertility status of the soils, the fertilizer needs of the crop, and the correlation between laboratory soil test data and crop responses to fertilizers. They were carried out in the fields of cooperators, under conditions of the customary planting, tillage, and irrigation practices of the farms. Plant populations ranged from 9,700 to 21,400 plants per acre. Experiments included rates of N application up to relatively high levels, with and without added P₂O₅; additional treatments included K₂O. Grain was analyzed for crude protein. Significant yield responses to N were obtained in 10 of 13 experiments. Maximum or near-maximum yields were produced, in most cases, by 100 lbs. N per acre. Protein content and total protein per acre in harvested grain increased with N application rate. Percentage of applied N recovered in the grain decreased with increased N. Efficiency of N in producing increased yield varied greatly with site and rate of N application. Very substantial residual effects of N applied to corn were observed on wheat the following year. No responses to P or K were found.
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