Influence of Fertilizers on the Yield of the Plamar Variety of Tomatoes on a Coto Clay

Abstract

The use of various fertilizer treatments on the Plamar variety of tomatoes growing on a Coto clay at the Isabela Substation revealed that: 1. The use of 100 pounds of N per acre gave significantly higher yields of commercial tomatoes per acre than either none or 200 pounds of N per acre. 2. Phosphate fertilizers increased tomato yields, the highest yields being obtained with 200 pounds of P₂O₅ per acre. 3. There was no response to potash fertilizers. 4. The use of 20 tons of filter-press cake per acre gave significant increases in yields over the no-fertilizer treatment. 5. When 20 tons of filter-press cake were used combined with 100 pounds of N and 200 pounds each of P₂O₅ and K₂O  per acre, the yields obtained were superior to those when the filter-press cake or chemical fertilizer were used alone. 6. No yield increases were obtained with magnesium and boron additions to the N-P-K fertilizer applications.