Yield Characteristics and Nutrient Use Efficiency of Potato ( Solanum tuberosum L.) Varieties Under Various NPS Fertilizer Rates in Mirab Azernet District in Central Ethiopia

The potato is crucial for food security among smallholder farmers in Ethiopia, but issues related to variety selection and fertilizer management often hinder its yield potential. A study conducted during the 2022 growing season in the Miarb Azernet district evaluated the performance of four potato varieties Local, Gera, Gudene, and Belete under different applications of nitrogen–phosphorus–sulfur (NPS) fertilizer rates (0, 50, 100, 150, 200, and 250 kg ha −1 ) using a randomized complete block design (RCBD) with three replications. The results revealed significant interactions between the potato varieties and NPS fertilizer applications, which affected key growth parameters and overall yield. The Belete variety showed outstanding results among the tested varieties when treated with 250 kg NPS ha −1 , resulting in a plant height of 97.85 cm, a marketable yield of 48.26 t ha −1 , a total yield of 49.68 t ha −1 , an average tuber weight of 75.44 g, and 46.21 tubers per hill. In contrast, the unfertilized Local variety yielded the least. Nutrient uptake and economic analysis indicated that applying 200 NPS kg ha −1 to the Belete variety resulted in the highest marginal yield of 79.1% and a significant net benefit of 693,740 ETB ha −1 . While these findings strongly support the use of Belete variety at 250 kg NPS ha −1 , further research is needed to validate these results and extend the recommendations to similar agroecological conditions and farming practices.