Effect of nitrogen sources and phosphorus rates on cassava (Manihot esculenta Crantz) yield in Supe, Perú

Abstract

Objective: To evaluate the effect of different nitrogen sources and phosphorus doses on cassava (Manihot esculenta Crantz) yield under the conditions of the Supe Valley, Lima Region, Peru. Methodology: A randomized complete block design with a 3×3 factorial arrangement was used, considering three nitrogen sources (urea, ammonium nitrate, and ammonium sulfate) and three phosphorus doses (120, 160, and 200 kg ha⁻¹). The variables evaluated were yields by commercial category (extra, I, and II) and total yield. Data were analyzed using analysis of variance and Tukey's test at the 5% significance level. Results: Highly significant differences (p ≤ 0.01) were found for the interaction between nitrogen source and phosphorus dose in all yield categories. Ammonium sulfate combined with 200 kg ha⁻¹ of phosphorus resulted in the highest total yield (58.67 t ha⁻¹), followed by ammonium nitrate (56.73 t ha⁻¹), while urea showed the lowest values. The results confirm a synergistic effect between ammoniacal nitrogen and phosphorus, which promotes nutrient absorption and root biomass accumulation. Conclusion: Ammonium sulfate with 200 kg ha⁻¹ of phosphorus is the most efficient combination for optimizing cassava yield in the soils of the Supe Valley.