Abstract:
Bread wheat is a major cereal crop in Ethiopia and in the study area, but its yield is
limited due to minimum use of improved varieties, diseases, weeds, low soil fertility and
lack of location specific fertilizer recommendation. Therefore, a field experiment was
conducted during the 2016 main cropping season at Bore Agricultural Research Center to
evaluate the effect of blended NPS and N fertilizer rates on yield components, yield and
grain protein content; and to determine economically appropriate rates of blended NPS
and N fertilizers for bread wheat production. The treatments consisted of four levels of
NPS (50, 100, 150 and 200 kg NPS ha-1) and four levels of N (23, 46, 69 and 92 kg N ha-1)
including one control (0 NPS and 0N). The experiment was laid out as a Randomized
Complete Block Design in a factorial arrangement with three replications. Analysis of the
results revealed that days to 90% maturity (DTM), grain protein content (GPC) and spike
length (SL) were significantly affected by the main effect of NPS as well as the main effect
of N while thousand kernel weight (TKW), hectoliter weight (HLW), plant height (PH) and
number of productive tillers (NPT) were significantly affected only by the main effect of N.
The maximum DTM (167.6 days), GPC (11.24%) and SL (8.43 cm) were recorded at NPS
rate of 150, 200 and 200 kg ha-1, respectively. Similarly, the maximum DTM (166.8 days),
GPC (11.35%) and SL (8.49 cm) were recorded at the highest rate of N (92 kg N ha-1).
Thus, as the rates of NPS and N increased, the DTM, GPC and SL were increased.
Likewise, the maximum TKW (44.13 g), HLW (84.25 kg hl-1), PH (94.03 cm) and NPT
(271.1 m-2) were obtained at the highest rate of N (92 kg N ha-1). The interaction of the two
fertilizers also significantly affected the above ground dry biomass (AGDB), days to
heading (DTH), grain yield (GY), harvesting index (HI), number of kernels per spike
(NKPS), number of tillers per plant (NTPP) and straw yield (SY). The highest AGDB
(18.87 t ha-1), DTH (83.67 days), GY (7.65 t ha-1), NTPP (3.76) and SY (11.218 t ha-1) were
recorded at combined application of 200 kg NPS + 92 kg N ha-1. However, the result of
economic analysis showed that combined application of 100 kg NPS and 92 kg N ha-1 gave
economic benefit of 42272.5 Birr ha-1 with the marginal rate of return 1728.3%. Therefore,
use of 100 kg NPS and 92 kg N ha-1 can be tentatively recommended for production of
bread wheat in the study area. Further research work over season and year would be
recommended for the study area.
