Estimation of a Common Nitrogen Response Function for Corn (Zea mays) in Different Crop Rotations
1966
Shrader, W. D. | Fuller, W. A. | Cady, F. B.
The premise that corn yields, over wide ranges of cropping systems, differ only because of differences in available nitrogen was tested using the criterion of whether corn yields in long term rotation experiments could be estimated by a common nitrogen response curve. Data from two experiments in Iowa were analyzed. Rotation intensities varied from continuous corn to a rotation with three years of meadow. Nitrogen rates ranged from 0 to 160 pounds per acre per year. Experimental designs, rotations and treatments were somewhat different at the two sites, but at each the corn yields could be fitted to a common nitrogen response curve. With this model rotation effects were expressed in terms of nitrogen units. Estimates of nitrogen equivalents, in addition to that available to continuous corn, supplied by the different rotations ranged from 10 to 130 pounds per acre.
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