Farmyard manure and intra-row spacing on yield and yield components of Adama Red onion (Allium cepa L.) cultivar under irrigation in Gewane District, Afar Region, Ethiopia

A field experiment was conducted at Gewane Agricultural Technical and Vocational Education and Training College in 2012/2013 to assess effect of farmyard manure and intra-row spacing on yield and yield components of Adama Red onion (Allium cepa L.) cultivar under irrigation.  Factorial combination of four rates of farmyard manure (0, 10, 20 and 30 t ha-1) and four levels of intra-row spacing (7.5, 10, 12.5 and 15 cm) were arranged in randomized complete block design with three replications. Significant effect of intra-row spacing on most of plant growth, bulb yield and bulb characters studied was noticed. Similarly, farmyard manure showed significant effect on mean bulb weight, weight loss, and bulb rotting. The interaction effects of intra-row spacing and farmyard manure rates showed significant influence on biological, total, marketable and unmarketable bulb yields. Highest total bulb yield, 58.74 t ha-1 and marketable bulb yields 57.77 t ha-1 were obtained from plants spaced at 7.5 cm and plots received 30 t ha-1 farm yard manure. The highest weight loss and bulb rotting were observed at wider intra-row spacing (15 cm) and highest farmyard manure application, which was 30 t ha-1. Intra-row spacing of 7.5 cm and 20 t ha-1 farmyard manure rate gave good marketable bulb yield and better storage life under the study area.   Key words: Bulb yield; farmyard manure; intra-row spacing; storage life.