Influence of Fertilizers on Yields of Pineapples on a Coto Clay

How to Cite

Samuels, G., Alers-Alers, S., & Jackson, G. C. (1958). Influence of Fertilizers on Yields of Pineapples on a Coto Clay. The Journal of Agriculture of the University of Puerto Rico, 42(1), 12–26.


This paper reports the results obtained in studies carried out on Red Spanish pineapples to determine their major- and minor-element fertilizer requirements for Coto clay soils. The experimental results may be summarized as follows: 1. Nitrogen was of prime importance in securing maximum yields of pineapples. The use of 480 pounds of nitrogen per acre gave the highest yields. 2. There was no significant response to phosphate fertilizers. 3. Yield responses were obtained from the use of potash fertilizers. 4. The number of fertilizer applications significantly influenced the yield of fruit; however, credit was due mainly to the total fertilizer applied—especially nitrogen. 5. The leaf analyses obtained were lower in nitrogen, phosphorus, and potassium than for other experiments. 6. Leaf-nitrogen values showed a significant correlation with relative yield of pineapples. 7. For Coto clay, leaf-phosphorus values of 0.09 percent and leaf-potassium values of 3 percent were associated with optimum yields of fruit. 8. The yields of pineapples were increased by the use of ferrous sulfate sprays. 9. Chelated iron as a spray or in soil applications gave no better results in increasing yields than ferrous sulfate sprays. 10. Iron malonate applied as a spray was unsuccessful in increasing pineapple yields. 11. The use of a glass frit containing iron and other minor elements held in a relatively slowly soluble form gave yields similar to the use of the ferrous sulfate sprays, but at a lower cost per acre. 12. Magnesium oxide and zinc sulfate did not increase yields on a Coto clay.


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