Influence of Phosphate Fertilizers on Pineapple Yields

Abstract

The use of phosphate fertilizers for pineapples has produced the following results in various experiments carried on by this Station: 1. From none to small yield increases were obtained with phosphate used at rates up to 56 pounds of P₂O₅ per acre and applied up to 4 months after planting. 2. Yields were depressed when 84 and 112 pounds of P₂O₅ per acre were applied. 3. The maximum quantity of phosphates that could be used for increasing yields under the experimental conditions was 56 pounds of P₂O₅ per acre. 4. The depressing influence of phosphates on yields is believed to be due to its action in lowering nitrate intake when carbohydrate and phosphate reserves are ample. 5. High-level phosphate additions serve to hasten pineapple fruiting and produce more culls. 6. At present growers use too much phosphate in their pineapple fertilizer applications, and a distinct saving in money could be realized if rates of phosphate application were lowered.