No abstract

Application of organic and inorganic fertilizers is essential for sustainable production of crops including potato. This study was therefore initiated to identify the optimum rate of farmyard manure (FYM) and blended compound NPS fertilizer for profitable production of potato in Koga Irrigation Scheme, Northwestern highlands of Ethiopia. Four rates of FYM (0, 4.5, 9, and 13.5 t ha −1) and NPS fertilizer (0, 81.7, 163.4, and 245.1 kg ha −1) were laid down in Randomized Complete Block Design with three replications. The results revealed that FYM and blended NPS fertilizer as well as their combination influenced most of the tested growth and yield parameters of potato including plant height, main stem number, and tuber weight. Application of 245.1 kg ha −1 NPS combined with 13.5 t ha −1 FYM recorded the highest marketable and total tuber yields of 43.52 and 47.04 t ha −1 , respectively. Although, the highest marginal rate of return was obtained from plants supplied with the combination of 4.5 t ha −1 FYM and 163.4 kg ha −1 NPS fertilizer, combined application of 245.1 kg ha −1 NPS and 13.5 t ha −1 FYM is recommended for economical production of potato in the study area as it recorded the highest net benefit with acceptable marginal rate of return.