Evaluation of grain protein content in Eragrostis tef for different N fertilizer application under irrigated condition

The decline in soil fertility and shortage of rainfall has been the main reason for the low productivity of Eragrostis tef (Zucc.), particularly in the northern part of Ethiopia. A field experiment was conducted to examine the impact of planting method and nitrogen fertilizer rates on the yield and protein content of irrigated Tef. The experiment consisted of four planting methods (pelleting, broadcasting, row planting, and transplanting) and six N fertilizer rate (0, 23, 46, 69,92 and 115 kg ha-1) combined in Factorial Randomized Complete Block Design (RCBD) with four replications. Seven response variables, heading date, maturity date, plant height, number of productive tillers, above ground biomass yield, grain yield, and grain protein content of Tef have been collected and analyzed. Analysis of variance showed that all parameters, with the exception of grain protein content, were significantly affected (P<0.05) by the interacting effects of planting methods and nitrogen levels. The highest values of all parameters were obtained from transplanting and N rate of 92 kg ha-1, although Tef plants receiving this treatment were extremely tall and were late in heading and maturity periods, which may have a negative implication Tef under rainfed system. In irrigated Tef, the nitrogen rate exponentially increased grain protein content until 92 kg ha-1N, which optimizes the nutritional quality of the crop, unlike the rainfed agricultural system.