The Interaction Effect of Nitrogen and Potassium Fertilization on Potato (So-lanum tuberosum L.) Yield

Abstract

Potato (Solanum tuberosum L.) is a globally important food crop, requiring balanced nutrient management to achieve high yield and quality. Nitrogen (N) and potassium (K) are two essential macronutrients where interaction plays a critical role in tuber development. This study was conducted at the Agricultural Research Station, University of Tripoli, Libya, to evaluate the effects of different nitrogen and potassium application rates and their interaction on potato yield. A split plot design with three replications was used, testing four nitrogen levels (0, 150, 225, and 300 kg N\ ha) and three potassium levels (0, 150, and 300 kg K₂O\ ha). Results showed that yield increased progressively with higher nitrogen rates, while potassium application further improved this response. The highest yield (36.8 t\ ha) was obtained at the combined application of 300 kg N ha⁻¹ and 300 kg K₂O\ha. Nitrogen application under zero potassium conditions produced comparatively lower yields, confirming that potassium enhances nitrogen use efficiency. Overall, the findings highlight that potato yield is maximized not through isolated nutrient application but through balanced N–K management. This study provides evidence for precision fertilization strategies that improve productivity, tuber quality, and sustainability under Libyan agro ecological conditions.