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

Abstract

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^-1nitrogen 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.