Influence of Various Phosphate Fertilizers on Yields of Red Spanish Pineapples in Puerto Rico

A Bayamón sandy clay was used to evaluate various phosphate sources for fertilizing Red Spanish pineapples. The phosphate sources utilized were simple superphosphate, triple superphosphate, raw-rock phosphate, ammonium metaphosphate, diammonium phosphate, calcium metaphosphate, dicalcium metaphosphate, potassium calcium pyrophosphate, and potassium metaphosphate. The results on a plant and a ratoon crop indicated that: 1. There were no significant increases in yield of Red Spanish pineapple for any of the phosphate sources used as compared to the no-phosphate treatment. 2. Yields were significantly lowered over the no-phosphate treatment when diammonium phosphate (20-52-0) was used as a source of phosphate. 3. Mean weight, but not total weight of fruit per acre, was significantly reduced over the no-phosphate treatment when potassium metaphosphate (0-47-28) was used as a source of phosphate.