Agronomic Investigations Using Continuous Function Experimental Designs—Nitrogen Fertilization of Sweet Corn1
- R. L. Fox2
Simple experimental designs are needed for exploratory field studies and for generating data for well defined yield response curves and surfaces. A design was developed by which a variable was increased in many small increments along corn (Zea mays L.) rows. Individual plants were handled as plots. Sweet corn was grown in rows 12 m long, along which rates of N fertilization increased in 40 increments from 0 to 220 kg/ha. Replication was obtained by repeating the layout but rotating it through 180 degees. “Border effects” along the row could be ignored because the incremental change of applied N was very small and because the N rate increased in one direction and decreased in the other. Because there are many experimental points it was possible to show that low rates of N produced a “diluting effect” on leaf N, that N deficiency symptoms disappeared and second ear develop ment began at about 140 kg N/ha, that lower corn leaves are the most sensitive indicators of the N status of corn, and that yield response to applied N was linear to 200 kg/ha of N applied. If a second factor is varied at right angles to the first, a well defined response surface can be obtained.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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