ISHS Acta Horticulturae 143: VIII African Symposium on Horticultural Crops
EFFECTS OF FREQUENCY OF IRRIGATION AND FERTILIZER NITROGEN ON YIELD AND QUALITY OF ONIONS (A. CEPA) IN THE ARID TROPICS |
| Author: | M. S. Hassan |
| Abstract:
Both irrigation water and fertilizers are rather expensive inputs in the production of vegetable crops in the Sudan. These investigations were initiated to ascertain the optimum irrigation intervals and fertilizer nitrogen levels that will produce high yields of good quality onions. The experiments were conducted in the Horticultural Research Farm of the Gezira Research Station in Wad Medani. Four irrigation intervals were used, viz: weekly, 10 days, 14 days and as required by the crop; coupled with three nitrogen levels, viz: no nitrogen; 90 kg N/ha; and 180 kg N/ha. Irrigating onions has highly significantly increased the total yield with the 7 and 10 day intervals obtaining the highest yield and the greatest average bulb weight. Increasing the water supply i.e. shortening irrigation intervals has reduced bolting but increased the amount of doubling of onions. Nitrogen application has similary affected yield with the 90 kg N/ha rate resulting in the highest yield and largest average bulb weight. Incidence of doubles and bolters were significantly increased by nitrogen application. No treatment interactions were detected. It was concluded that a combination of 90 kgN/ha together with an irrigation interval of 10 days should give optimum onion yields of good quality. | |
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