Effects of transplanting date, nitrogen nutrition and watering regime on yield, quality and storage of the red onion

• Main Author: Nourai, A.H. (Agricultural Research Corporation, Shambat Research Station, P.O. Box 30, Khartoum North, (Sudan))
• Format: Publication
• Language: English
• Published: Wad Medani (Sudan) Agricultural Research and Technology Corporation Unit 2006
• Subjects: ALLIUM CEPA; ALMACENAMIENTO; HORTICULTURA; HORTICULTURE; NITROGEN RETENTION; REGIME HYDRIQUE DU SOL; REGIMEN HIDRICO DEL SUELO; RENDEMENT; RENDIMIENTO; REPIQUAGE; RETENCION NITROGENADA; RETENTION AZOTEE; SOIL WATER REGIMES; SOUDAN; STOCKAGE; STORAGE; SUDAN; TRANSPLANTING; TRASPLANTE; YIELDS

Field experiments were conducted for three consecutive seasons (1989-90, 1990-91 and 1991-92) with the objective of evaluating the effects of three transplanting dates (15 Nov, 15 Dec and 15 Jan), two levels of nitrogen nutrition (43 and 86 kg N ha-1) and two watering regimes (5 and 10 days) on yield, quality and storage of the red onion variety 'Saggai Improved'. The highest total onion yield (25 tons ha-1) was realized in 1989-90 season while the lowest total yield (17 tons ha-1) was recorded in 1990-91 season. This seasonal variations in onion yields were attributed to the variations of temperatures prevailing during the growing season where high onion yields were realized in the winter seasons. High onion yields were realized from early transplanted crop (15 Nov.) followed by 15 Dec. and then 15 Jan. transplanted onion. Percentage reductions of 76 and 56 were recorded when the total and marketable yield averaged over the three seasons of on ion transplanted in 15 Jan. were compared with the total and marketable yield averaged over the three seasons of onion transplanted in 15 Nov. The high onion yields realized from early transplanting were associated with an increased bulb size, increased incidence of doubles and splits and bolters, and an improved quality and plant stand. However storage losses were higher in early transplanted onion. The application of nitrogen fertilizer in the form of urea increased onion yield in one out of three seasons. Increases of 7 and 5 tons ha-1 in total and marketable onion yields, respectively were recorded when onion plants were irrigated every 5 days as compared to the yields of onion irrigated every 10 days. Based on the findings of this study and in order to achieve high onion yields it is recommended that onion could be transplanted during the period 15 Nov. to 15 Dec