Authors:A. Kandil, A. Attia, A. Sharief, and A. Leilh
Two field experiments were conducted at the Experimental Station of the Faculty of Agriculture, Mansoura University, Egypt, during the 2006/2007 and 2007/2008 seasons. The results showed that a gradual increase in soil water tension from 24 centibars (cb) (5588.25 m3/ha), i.e. 56.3% field capacity to 36 cb (2634.49 m3/ha), i.e. 41.% field capacity, significantly decreased the average onion bulb weight (g), bulb diameter (cm), bulb length (cm), total bulb yield (t/ha) and marketable bulb yield (t/ha) and significantly reduced the total percentage loss after 2, 4 and 6 months in both seasons. Conversely, this increase in water tension significantly amplified the culled bulb yield (t/ha), bulb dry matter (%) and water use efficiency (kg/m3). Normal water supplies (24 cb) clearly led to high percentage losses in bulb dry weight compared to the other water stress treatments. The results indicated that the application of 75% NPK plus the bio-fertilizer Soft Guard significantly improved the average bulb weight (g/plant), bulb diameter (cm), bulb length (cm), total bulb yield (t/ha), marketable bulb yield (t/ha) and dry matter (%) compared with the other fertilization treatments.