Effect of Various Levels of NPK on the Yield, Sugar Content and Sugarcane Leafhopper (Pyrilla perpusilla) on Sugar Cane (Saccharum officinarum L.)

A field experiment was conducted to evaluate the response of sugarcane (Saccharum officinarum L.) to varying levels of nitrogen, phosphorus, and potassium (NPK) fertilizers in plant and ratoon crops. Yield data revealed that fertilizer treatments significantly influenced cane tonnage and sugar recovery at both the 5% and 1% probability levels. In the plant crop, the highest cane yield (68.9 t ha⁻¹) was obtained with 168 kg N ha⁻¹, while the maximum sugar percentage (10.67%) was recorded with 112–56–56 NPK kg ha⁻¹. Increasing N beyond the optimum level did not significantly improve yield and tended to depress sugar recovery. In the ratoon crop, the highest cane yield (72.86 t ha⁻¹) was achieved with 168–56–56 NPK kg ha⁻¹, indicating the necessity of balanced P and K supplementation in ratoons. Although a slightly higher sugar percentage (9.94%) was observed at 224 kg N ha⁻¹ alone, yield at this level was significantly lower than at balanced NPK. Fertilization also reduced Pyrilla infestation, with minimum incidence (12.77%) observed at 224–56–112 NPK kg ha⁻¹. Overall, results suggest that 168–56–56 NPK kg ha⁻¹ represents the optimum fertilizer regime, balancing cane yield, sugar recovery, and pest tolerance, with higher rates leading to diminishing returns. These findings align with recent studies emphasizing nutrient balance, split N applications, and ratoon-specific P and K management as key strategies for sustaining cane productivity and sugar recovery.