Effect of Set Size and some Fertilizers on Early Season Onion (Allium cepa. L) Production

Abstract

This study was conducted in off-season 2015 at the Experimental Farm of Shambat Research station, Agriculture Research Corporation, Khartoum, Sudan, to investigate the effect of large and medium set sizes (2-3cm and 1-2 cm in diameter, respectively) of onion variety Baftaim (S) and two chemical fertilizer (Urea and NPK) in addition to organic fertilizer (Elkhaseeb) and their combinations (Urea + Elkhaseeb and NPK+ Elkhaseeb) .The experimental units were in complete randomized block design arranged in split plots with three replications. The vegetative growth was evaluated as plant height, number of leaves and leaf length, and the yield and quality as total, marketable and unmarketable yield, percentage of doubling and bolting bulbs and other bulb characteristics (bulb diameter and length, neck diameter, number of rings, total soluble solids and dry matter). The results reflected that the vegetative growth was not affected by the set size or single fertilizers (Urea, NPK or Elkhaseeb alone). However, the highest vegetative growth was obtained by the combinations of organic and chemical fertilizers. The medium set size gave the highest total and marketable bulb yield and the lowest percentage of bolting bulbs. Application of organic fertilizer alone or in combination with mineral fertilizers recorded the highest total and marketable yield and quality (low percentage of double and bolting bulbs and high total soluble solids and dry matter); especially with the medium set size. Further studies for optimum fertilizer rates are required.