Response of Sugarcane to Fertilizers on an Organic Soil

Abstract

A fertilizer experiment using sugarcane variety P.R. 980 on a Tiburones muck at Caño Tiburones was carried on for a plant cane and two ratoons. The major results were: 1. Nitrogen fertilizers gave no response in cane tonnage, sucrose-percentcane, or tons of sugar per acre. 2. There was a highly significant response to phosphate fertilizers at the rate of 150 pounds P₂O₅ per acre in cane tonnage. The use of 300 pounds P₂O₅ per acre gave no significant increase over the level of 150 pounds of P₂O₅ per acre. 3. Cane tonnage was significantly increased with the use of 300 pounds of K₂O per acre, but not with 150 pounds of K₂O per acre. 4. Sucrose-percent-cane responses to the fertilizers were variable, ranging from a decrease in sucrose caused by nitrogen in the plant cane to significant increases attributable to phosphorus for the plant cane and to potash for the plant cane and second ratoon. 5. Tons of sugar were significantly increased under 150 pounds of P₂O₅ and 300 pounds of K₂O per acre. 6. Leaf-phosphorus values were significantly correlated with the relative yields of 96° available sugar per acre. A leaf-phosphorus value of 0.17 percent or above was associated with no response to phosphate fertilizers. 7. Leaf-potassium values were not as significantly correlated to sugar yields as leaf-phosphorus. Leaf-potassium values of 1 percent was associated with relative yields of sugar of 75 percent, and the cane responded to potash applications.