Malting Barley Grain Quality and Yield Response to Nitrogen Fertilization in the Arsi Highlands of Ethiopia
2019
Kassie, Meharie | Tesfaye, Kindie
The malting industry in Ethiopia is often challenged by the availability of barley that meets the quality and quantity requirements set by the industry. Field experiments were conducted to evaluate (i) the effects of nitrogen (N) fertilization rate, variety and growing season on grain yield and grain characteristics of malting barley, and (ii) to determine the N rate that optimize grain yield and quality of malting barley. The treatments studied were five N levels (0, 23, 46, 69, and 92 kg ha₋₁) and two malting barley varieties (Holker and Miscal-21) over three growing seasons (2012, 2013, and 2014). The results showed that as N rates increased, malting barley grain yield, grain and straw N concentration, grain protein content, 1000-kernel weight and kernel plumpness increased, but N rates had no effect on hectoliter weight. Grain yield, grain N concentration, grain protein content, kernel plumpness and 1000-kernel weight were greater in Miscal-21, whilst straw N concentration and hectoliter weight were greater in Holker. Grain yield and hectoliter weight were affected by seasonal conditions, but grain and straw N concentration, grain protein content, kernel plumpness, and 1000-kernel weight were not affected. Although both grain yield and protein content increased with increased N rates, based on the regression equation, application of 48 kg N ha₋₁ gave the highest net benefit and marginal rate of return with acceptable grain quality (protein content < 11.5% and kernel plumpness > 85 g kg₋₁). Application of N beyond 48 kg ha₋₁ did not increase net benefit, but instead increased cost of production. In conclusion, to improve the likelihood that barley will be acceptable for malting, growers should limit N application and select varieties with low protein content.
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