Influence of Nitrogen Rate on Nitrogen use Efficiency and Quality of Potato (Solanum tuberosum L.) Varieties at Debre Berhan, Central Highlands of Ethiopia

Abstract

Background and Objective: Potato is an important crop grown by many smallholder farmers in the central part of Ethiopia. However, the productivity of the crop is low which is mainly attributed to poor soil fertility and improper application of fertilizers. Thus, this field experiment was conducted to study influence of nitrogen rate on nitrogen use efficiency and quality of potato (Solanum tuberosum L.) varieties at Debre Berhan, Central Highlands of Ethiopia. Material and Methods: Factorial experiment of six nitrogen rates (0, 46, 92, 138, 184 and 230 kg N haG 1 ) and two varieties (Gera and Gudene) were arranged in randomized complete block design scheme with three replications. The collected data were subjected to ANOVA using SAS-GLM procedure. Results: The total N uptake and concentration in above ground part were raised by two and three folds, respectively with application of 230 kg N haG 1 that had increased N concentration in tuber by 57.17% and soils after harvest by 20.87% as compared to the control. Generally, the highest values of total dry matter, above ground biomass, total plant dry matter and medium size tubers were found at the 184 kg N haG 1 rate. However, the maximum amounts of agronomic and physiological N efficiencies were recorded at 46 kg N haG 1 that had the highest percent of apparent N recovery and N harvest index. Conclusion: The finding of this study had revealed that N had significant impact on production of quality potato tubers and nitrogen use efficiency. Generally, 184 kg N haG 1 showed the highest dry matter accumulation with good apparent nitrogen recovery and agronomic nitrogen use efficiency, beyond which there were poor efficiency and non-significant difference.