Nitrogen Uptake and Use Efficiency of Wheat (Triticum aestivum L.) Varieties as Influenced by Combined Application of Vermicompost and Nitrogen Fertilizer Rate

: Crop management strategies that improve nitrogen use efficiency and increase profits while reducing the detrimental effects on the environment due to loss of nitrogen fertilizer. A study was conducted in 2019 cropping season to evaluate effectiveness of vermicompost, N fertilizer and their combinations in improving nitrogen uptake and nitrogen use efficiency at Holeta Agricultural Research Center. The experiment was designed in a split-split-plot combination with wheat varieties (Wane and Danda’a) as main plots, four vermicompost rates (0, 2.5, 5 and 7.5 t ha -1 ) as sub-plot and four N fertilizer rates (0, 23, 46 and 69 kg N ha -1 ) as sub-sub plot with three replications. Synergistic nutrient interaction effect sourced from vermicompost and urea fertilizer brought positive influence on wheat nitrogen uptake and use efficiency. The highest (154.33 kgha -1 ) total nitrogen uptake was obtained from combined application of Wane variety together with 5 t ha -1 vermicompost and 46 kgha -1 of nitrogen fertilizer while the lowest value (33.21kgha -1 ) was obtained from control plot. Maximum grain nitrogen use efficiency (93.45 kg kg -1 ) was recorded from plot that received Wane variety with 23 kg N ha -1 and the value decreased as vermicompost and N fertilizer level increased while the lowest (29.63 kg kg -1 ) value was obtained when Danda’a variety used with vermicompost at 7.5t ha -1 and 69 kg ha -1 nitrogen fertilizer. Similarly, the highest nitrogen apparent recovery efficiency (111.42%) and agronomic efficiency (42.59 kg kg -1 ) were observed in treatment that received Wane variety with combined application of vermicompost at 5 t ha -1 and nitrogen at 46 kg ha -1 while the lowest value was respectively obtained from Danda’a variety with nitrogen at 69 kg ha -1 and Danda’a variety with vermicompost at 2.5t ha -1 . The maximum (72.64%) N harvest index was recorded from variety Wane when applied with combination of vermicompost at 2.5t V ha -1 and nitrogen at 46kgha -1 , but the minimum (61.98%) value was recorded from application of vermicompost at 7.5tha -1 . Therefore, integrated use of variety, vermicompost and nitrogen fertilizer is found to be better in enhancing nitrogen fertilizer efficiency and reducing environment problems.