Fertilizer Evaluation: II. Estimation of Availability Coefficients
1956
White, R. F. | Kempthorne, O. | Black, C. A. | Webb, J. R.
Response curves produced when plants are grown on soils treated with different rates of fertilizers are used as the basis for estimating the ratio of the availability coefficient of a nutrient in one fertilizer to that in another. A least squares method is described and illustrated for fitting each of three types of response curves. Concurrent linear response curves are illustrated by data on yield of phosphorus. Parallel linear response curves for log response against log rate of application are illustrated by data on content of radioactive phosphorus. Concurrent Mitscherlich curves with the same initial and limiting responses but different rates of increase are illustrated by data on yield of corn grain.
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