Shallot yield, quality and storability as affected by irrigation and nitrogen

摘要

Field experiments were conducted to evaluate growth, yield and quality of shallot (Allium cepa var. ascalonicum Baker) under three levels of irrigation and nitrogen fertilization, on a clay soil in the sub-humid tropical climate of eastern Ethiopiafrom 1999 to 2002. Treatments comprised furrow irrigation at three moisture levels (75, 50 and 25 percent available soil moisture) and three nitrogen levels (0, 75 and 150 kg ha~(-1)), using two local shallot cultivars. Bulb yield and mean bulb weight ofboth cultivars were higher at irrigation levels of 75 percent than at 50 percent or 25 percent available soil moisture. Total weight and rotting losses of bulbs were highest at the irrigation level of 75 percent and least at 25 percent available soil moisture in the cultivar 'DZ-sht-91', while in cultivar 'Fedis' irrigation treatments did not affect storability. The best irrigation water-use efficiency was obtained with irrigation at 50 percent available soil moisture. Nitrogen at 75 or 150 kg ha~(-1)increased the pyruvic acid content of bulbs. Application of nitrogen tended to increase mean bulb weight in 'Fedis' while 'DZ-sht-91' receiving no nitrogen had heavier bulbs. No significant effects were observed on the yield, dry matter, soluble solids and storability of bulbs due to the nitrogen fertilization. No interaction effects were observed between N and irrigation treatments. Irrigation at 75 percent available soil moisture is suggested for shallots destined for immediate use.