Interaction Effects of In-organic N- Fertilizer and Seed Rates on Yield and Quality Traits of Malt Barley Varieties in the Highland of Tigray, North Ethiopia.

Abstract

A new brewery factory has been constructed in Tigray region. In response, farmers are concerned to produce and earn premium price from malt barley. Besides, quality prerequisites for malting barley are objectively strict and mostly controlled by the growers crop management practice. However, there is limited/no information on the fertilizer and seed rate requirement of the crop that can achieve high quality malt without compromising yield and profit. Therefore, this research was aimed to determine the appropriate levels of inorganic N-fertilizer and seed rate on the yield and quality of malt barley varieties in three districts of Southern Tigray, North of Ethiopia. Treatments include two malt barley varieties (V1=Bekoji-1 and V2=Bhatty), seven N- rates (N0=0, N1=23, N2=34, N3=46, N4= 57.5, N5= 69 and N6=80.5 Kg N ha^-1) in the form of Urea and two levels of seed rates (SR1=100, SR2=150 kg ha^-1). The design was split-split plot with three replications. Varieties were put as a main plot, seed rate as a sub plot and the N-rates as a sub sub-plot treatment. The analysis of the separate and combined over locations revealed significant differences on grain yield (GY) and malt quality traits due to the main effect of treatments and some interactions. The effect of variety and seed rate were non-significant in response to GY. Highest value of grain yield (GY), hectoliter weight, plumpness, thousand kernel weight and acceptable grain protein content (GP) for malt barley was recorded at N5. The treatment without N-fertilizer application showed the least performance in above ground biomass and grain yield and malt quality traits. From the interaction of factors acceptable GP and higher grain yields were obtained from combinations: V2xSR1xN5 (GP=11.22%) and V1xSR1xN5 (GP=12.50%) at Ofla and V2xSRIxN6 (GP=12.28%) and V2xSRIxN5 (GP=12.09%) at Enda-Mekoni and V1xSR1xN5 (GP=11.94%) and V2xSR1xN5 (GP=11.44%) at Emba-Alaje. V2 x SR1 x N5 was selected as best combination in all locations. Bekoji-1(V1) at higher N-rates (N5 & N6) and SR1 at Enda-Mekoni was beyond the maximum acceptable limit in grain protein content. Regarding the profitability of the package highest net benefit and MRR were obtained from the application of N5 fertilizer rate at SR1 for both varieties in all study areas. Therefore, under similar environmental conditions the combination of V2 x SR1 x N5 is the best agronomic package for both grain yield and acceptable malt quality at all locations. In addition combinations of V1xSR1 xN5 can also be recommended for Ofla and Emba-Alaje districts.

Keywords: Grain Protein, grain yield, N-fertilizer, Profit, seed rate, variety