Proper type and amount of fertilizer application is the major factor that affects grain quality of durum wheat. Hence, field experiment was carried out on farmer’s field to determine the effect of blended NPS in combination with nitrogen on grain quality of durum wheat during 2016 cropping season. Factorial combinations of three blended NPS levels (100, 150, and 200 kg ha-1) each supplemented with five levels of nitrogen (0, 23, 46, 69 and 92 kg ha-1) and control (no fertilizer application) were laid out in a randomized complete block design with three replications. The Interaction of blended NPS and N rate were not significantly influenced the grain quality of durum wheat. Moreover, the main effect of blended NPS had no significant effect on all durum wheat grain quality parameters. However, the main effect of supplemented N had significant effects on some grain quality of durum wheat. The maximum grain protein content (14.19%), wet gluten content (40.43%), dry gluten content (12.59%) and vitreousness (93.64%) were achieved at application rate of (92 kg N ha-1). The result indicated that application of 100 kg NPS ha-1 with 69 kg N ha-1 supplementation were recommended for farmers in Negelle Arsi District and other areas with similar Agro-ecological conditions.

Keywords: blended NPS, durum wheat, grain quality, supplemented N.