Economic Performance and Nutrient Use Efficiency of Onion (Allium Cepa L.) Under N, K and S Nutrient Combinations in Northern Ethiopia

Background: Nitrogen (N), potassium (K) and sulfur (S) nutrient elements play an important role in the growth and bulb yield of onion. However, imbalanced nutrient application leads onion producers to get lower onion bulb yield. Hence, the supply of adequate and balanced plant nutrients is important in order to achieve better nutrient utilization as well as proper growth and high yield. Objective: To evaluate the agronomic and economic performance as well as nutrient efficiency of onion in response to the combined application of nitrogen, potassium and sulfur nutrient levels. Method: The field experiment was conducted during 2016/17 to test agronomic, economic and nutrient use efficiency of eighteen treatment groups with the combination of three levels of N, three levels of K and two levels of S nutrient on onion using a randomized complete block design. Results: The combined application of N, K and S nutrient levels appreciably resulted in significant variation not only on growth and bulb yield of onion but also on the economic performance and nutrient use efficiencies. Increased growth and improved bulb yield of onion as well as better nutrient uptakes and recoveries were observed in plots treated with relatively higher NKS rates. However, enhanced Agronomic Efficiency (AE) and Partial Factor Productivity (PFP) were obtained from plots treated with no N and K nutrient applications. Conclusion: Higher growth, improved bulb yield and enhanced nutrient use efficiencies (nutrient concentrations, uptakes and recoveries) were obtained from onion plants cultivated using a relatively higher NKS nutrient level. However, from the economic point of view, onion production using combined application of 69 kg N ha-1and 15 kg S ha-1was the most profitable, irrespective of the K level.