Effect of Integrated Application of Farmyard Manure and Inorganic Nitrogen on Yield and Yield Components of Onion (Allium cepa L.) Cultivars in Middle Awash Valley, Ethiopia

Abstract

The Middle Awash Valley regions of Ethiopia have a privileged location for onion production and marketing, with a potential demand exceeding the actual production capacity of the growers. Recently, large and small-scale onion farms are booming at every corner of the Awash River. However, their yield level remained low due to low soil fertility, low access to improved technologies, and poor agronomic practices in the area. To find out the reasons a field experiment was carried out at students’ demonstration farm of Gewane Agricultural TVET College, Middle Awash Valley, Ethiopia. The objective of the study was to evaluate effects of the integrated application of farmyard manure (FYM) and nitrogen (N) on bulb yield of onion. The experiment was laid out in a randomized complete block design and treatments were replicated three times. Treatments consisted of two onion cultivars (Adam Red and Melkam) and six soil amendments: Control (unfertilized), 50 kg N ha-1, 37.5 kg N + 4 t FYM ha-1, 25 kg N + 8 t FYM ha-1, 12.5 kg N + 12 t FYM ha-1 and 16 t FYM ha-1. The results showed that all traits were significantly (P < 0.05) affected by cultivar and soil amendment. Onion cv. Melkam recorded higher biomass yield (11%), bulb yield (13%), single-bulb weight (23%) and marketable yield (14%) than those recorded with cv. Adama Red. As compared to control, soil amendment had increased the total dry biomass yield, bulb yield, single bulb weight and marketable yield, respectively, by 41-90%, 30-60%, 23-53% and 37-71%. The application of 37.5 kg N in combination with 4 t FYM ha-1
recorded maximum dry matter yield (7.8Mg ha-1), bulb yield (43.67 Mg ha-1), mean bulb weight (215.5 g/bulb) and marketable yield (41.57 Mg ha-1) while minimum values of these parameters were obtained from the control treatment. Therefore, the study identified that growing of variety Melkam with integrated application of 37.5 kg N and 4t FYM ha-1 would be the best option to improve onion yield in the study area.

Keywords: Adama red, bulb yield, marketable yield, Melkam, onion