Yields of pineapples as influenced by fertilization and conformity to the law of diminishing increment
1932
Magistad, O.C. | Farden, C.A. | Lambert, C.B.
1. The authors have taken the yield data from one field experiment involving potash fertilization on pineapples and constructed yield curves. Such yield curves have been constructed for the plant crop and for the cycle crop, which in this case consists of plant and first ratoon. 2. The authors have made a number of yield curves and others, as well as the ones here submitted, convince them that yield increases attributed to fertilization very often follow mathematical expressions such as those set up by Mitscherlich and Spillman. 3. Attempts have been made to incorporate in this paper the mathematical methods of securing the best fit for yield curves and for other derived values so that they would be available in a widely circulated journal in the English language. The authors wish to give credit to other workers for many of the mathematical methods used. 4. It has been shown how the quantity of plant food arising from the soil can be calculated from yield curves. This constitutes a method of soil analysis which involves only yield data and computations upon them. This quantity, called by Mitscherlich the "b" value, may possibly serve as a good criterion as to the reliability of chemical soil analyses. 5. Any indicator crop used in the greenhouse will correctly forecast results in the field if on the same soil the R values are identical or if they always bear a constant value to each other. Yield curves thus serve to evaluate the suitability of indicator crops. This is of special importance with large crops having a long growing season, such as pineapples, sugar cane, bananas, and tree crops.
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