Effects of Nitrogen and Blended Fertilizers on Yield and Yield Components of tef [(Eragrostis tef (Zucc.) Trotter] in Central Highlands of Ethiopia

Tef is a highly valued crop in the national diet of Ethiopians and the major crops grown in central highlands of Ethiopia. However, its productivity is constrained by low plant-available soil nutrients due to depleting soil organic matter content and long history of intensive cultivation. Therefore, a field experiment was carried out at Debrezeit agricultural research center in Ada'a district during the 2017 main cropping season with the objective of to assessing the effect of N and blended (NPSZnB) fertilizers on yield and yield components of tef, nutrient uptake and verifying economically feasible rates of N and blended NPSZnB fertilizers for high yield of tef production. The experiment consisted four levels of nitrogen (0, 46, 92 and 138 kg N ha-1) and five levels of blended (0, 100, 150, 200 and 250 kg NPSZnB ha-1) in factorial combinations using Kora tef variety as a test crop. The experiment was laid out in RCBD with three replication. The result revealed that the main effects of N rates were significant (P<0.01) in terms of total number of tillers, aboveground dry biomass and lodging index. The highest values were recorded at the rate of 138 kg N ha-1. Similarly, the main effect of blended fertilizer was highly significantly (P<0.01) on aboveground dry biomass yield and straw yield, where by the highest value were recorded at the rate of 250 kg NPSZnB ha-1. The interaction of N and blended fertilizer significantly (P<0.05) affected plant height, effective tillers, harvest index and days to heading. The highest plant height, effective tillers ,harvest index and days to heading were obtained at combined application of 138 kg N ha-1 and 200 kg NPSZnB ha-1 , 46 kg N ha-1 and 150 kg NPSZnB ha-1 92 N kg ha-1 and 100 kg NPSZnB ha-1 ,and un-fertilized plot, respectively. The interaction also significantly (P<0.01) affected grain yield and the maximum (2002.5 kg ha-1) was obtained at combined application of 92 kg N and 100 kg NPSZnB ha-1, Moreover, N,S,Zn and B uptake in grain and straw were significantly affected by the interaction of N and blended fertilizers rate. The highest N, Zn and Boron uptake in grain were obtained at the combined application of 92kg N and 100 kg NPSZnB ha-1 fertilizer rates. The post-harvest soil analytical result showed insignificant (P>0.05) influence of the fertilizers, except for the available Zn. Applying 100 kg blended NPSZnB ha-1 supplemented with 92 kg N ha-1 had the highest net benefit, relatively low variable cost together with highest and acceptable MRR for tef production in Ada'a district. However, since the experiment was conducted only for one season and one site, repeating the trial at different sites as well as on the same trial site would be important to draw sound recommendation.