Abstract:
The major Ethiopian users of malt are the domestic breweries though their annual demand
has not so far been met by the domestic malt supply. Regardless of immense potential for
producing malt barley in Ethiopia, its production is limited due to many constraints including
poor soil fertility and low pH. Accordingly, a study was carried out during main growing
season of 2017 to investigate the effects of N and P fertilizer rates on yield, yield components
and quality of malt barley. A malt barley variety IBON-174/03 was used as test crop. Four
levels of N (0, 46, 92 and 138 kg ha
-1
) in the form of urea and four levels of P
(0, 23, 46
and 69 kg ha
-1
) in the form of TSP were used as experimental treatments. The experiment was
laid out in RCBD with three replications. Statistical analyses of data showed that most of the
parameters including the grain yield were significantly affected by the main effect of N, but
not respond to P
2
O
5
due to the availability of high
amount of phosphorus in the soil. The
maximum grain yield (4735.20 kg ha
-1
2
O
) was obtained from the application of 138 kg N ha
.
The graph of regression analysis indicates that there is a linear relationship between N
fertilizer rates and grain yield. With respect to malt quality parameters, the optimum total
protein (11.90%) and soluble protein (4.20%) were obtained at the fertilizer rate of 92-0 kg
N-P
2
O
5
ha
-1
respectively. Based on partial budget analysis, the maximum net benefit of
(82006.18 ETB) was obtained under the application of 138-69 kg N-P
2
O
5
ha
. However, the
grain yield from this combination was beyond the acceptable protein content for brewing
purpose. Conversely, 92-0 kg N-P
2
O
5
ha
-1
-1
produced optimum (3613.30kg ha
) with
acceptable protein content and malt extract for malt barley production in the study area.
Thus, application of 92 kg N ha
-1
can be recommended for the farmers in the study area and
areas with similar agro-ecological conditions. However, as the study was for one season,
such research has to be repeated over several seasons to give a conclusive recommendation.
5
-1
-1
