Nitrogen Uptake and Utilization Efficiency of Malting Barley as Influenced by Variety and Nitrogen Level

Abstract

Nitrogen (N) is the primary driver of crop production and it is heavily used in modern agriculture to maximize yield. However, the effectiveness with which N is used by cereals has become increasingly important because of both financial and environmental costs to N fertilization. The aims of this study were to determine the effects of N fertilization rate, variety, and growing season on grain yield, N uptake, and N-efficiency traits of malting barley at Bekoji, southeastern Ethiopia. The treatments studied were five N levels (0, 23, 46, 69, and 92 kg ha-1) and two malting barley varieties (Miscal-21 and Holker) over three seasons (2012, 2013, and 2014). The results showed that as N rates increased, malting barley grain yield, grain, straw, and total N uptakes increased, but N-harvest index, N-use efficiency, N-recovery efficiency, and N-utilization efficiency decreased. Grain yield, grain, and total N uptake, N-harvest index, N-use efficiency, N-recovery efficiency, and N-utilization efficiency were greater in Miscal-21, whilst straw N uptake were greater in Holker. Grain yield, grain, straw, and total N uptake, N-recovery efficiency, and N-harvest index were greater in 2012 than in 2013 and 2014, but growing season had no effect on N-use efficiency and N-utilization efficiency. Grain yield was positively correlated with N-efficiency traits, but the role of N-recovery efficiency in enhancing grain yield was larger than the role of N-utilization efficiency.