Effect of NP and Blended NPSB Mineral Fertilizer on Black Cumin Yield in Central Highlands of Ethiopia

Black cumin (Nigella sativa L) is an important spice and medicinal plant cultivated in Ethiopia. However, the seed yield of the crop is low due to low soil fertility and poor soil fertility management. A field experiment was conducted to determine the effect of nitrogen and phosphorus (NP) and blended nitrogen, phosphorus, sulfur, and boron (NPSB) fertilizers on seed yield and yield components of black cumin. The experiment consists of three levels of N/P2O5 (20/15, 40/30, and 60/45 kg N/P2O5 ha–1 in the form of UREA and tri-super phosphate); and four levels of blended NPSB (0, 50, 100 and 150 kg ha–1) laid in RCBD design arranged in a factorial and replicated three time. The research was conducted during the 2017/18 primary season in the central highlands of Ethiopia. The interaction of NP and blended NPSB significantly influenced yield and yield components (P ≤0.01). The application of 40/30 kg N/P2O5 and 150 kg blended NPSB ha–1 resulted in the highest seed yield (1.85 t ha–1) and the highest net benefit of (78,137 ETB ha–1). Therefore, the application of 40/30 kg N/P2O5 and 150 kg NPSB ha–1 resulted in more than double the current national average yield and benefits black cumin-producing farmers in the central highlands of Ethiopia.