Response of Potato (Solanum tuberosum L.) Varieties to Blended Nitrogen, Phosphorus and Sulfur Fertilizer Rate at Kokate, Southern Region

Low production and productivity of potato in Ethiopia is associated with poor soil fertility and limitation of high yielding crop variety. Matching high yielding cultivar with optimum fertilization of balanced nutrients is of paramount important to boost tuber yield of potato. Hence, a field experiment was conducted during 2019/20 cropping season at Kokate testing site of Areka Agricultural Research Center in southern Ethiopia in order to evaluate the response of potato varieties to NPS fertilizer rates. Treatments used in the study were two improved varieties of potato (Gudane and Belete) one local cultivar with six rates of blended NPS (0, 50, 100, 150, 200 and 250 kg/ha NPS) combined in factorial and laid out in a randomized complete block design with three replications. As this investigation indicated that at all rates of NPS fertilizer, improved varieties out yielded the local cultivar Asmara with relative superiority of variety Belete for marketable tuber yield. Economic analysis revealed that the highest net benefit of 276326 Birr/ha with marginal rate of return (MRR) 3762% was obtained from variety Belete at NPS fertilizer rate of 200 kg/ha followed by variety Gudane at the same fertilizer rate with net benefit of 270350 Birr/ha and MRR of 3372%. Based on this finding, varieties Belete and Gudane could be used for production at NPS fertilizer rate of 200 kg/ha near study area and similar agro-ecologies.