الفهرس 
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Abstract
This investigation was conducted during the two successive winter seasons of 2006/2007 and 2007/2008 at the Experimental Station Farm, Faculty of Agriculture, Mansoura University, Dakahlya Governorate.
The present study aimed to evaluate how effective of some furrow irrigation schedules (on the basis of soil water depletion) and fertilizer treatments (combined as the compensation of mineral fertilizers by some bio-fertilizers) on onion growth, yield, quality and storability.
The most important results obtained from this investigation can be summarized as follows:
I- Irrigation tension effect
Increasing watering stress from 24cb through 36cb significantly decreased foliage height after 90 and 120 DAT and markedly decreased crop growth rate. Moreover the results indicated that increasing irrigation tension from 24cb (2328.39 m3/fed) through 36cb (1097.70 m3/fed) markedly increased TSS and bulb dry matter (%) and decreased total bulb yield (t/fed) by 8.54% over both seasons.
II- Mineral and bio-fertilization effect
Application of 100% NPK fertilizer ( normal recommendation ) at (100 kg N+ 30 kg P2O5+24 kg K2O/fad) significantly increased total bulb yield of onion compared with 75% NPK + water (75 kg N + 22.5 kg P2O5 + 18 kg K2O/ fad) + water in both seasons. Application of Amino Total at 1000 ppm plus 75% NPK fertilizer combination or Soft Guard at 4000 ppm plus 75% fertilizer combination significantly recorded the maximum total bulbs yields, if compared to the combined application of Alga 600 at 1000 ppm or Algreen at 3000 ppm plus 75%NPK fertilization.
Application of 100% NPK fertilization + water treatments i.e. 100 kg N + 30 kg P2O5 + 24 kg K2O/fad significantly recorded the heighst onion bulbs losses during storage period after 2, 4, 6 months and total losses percentage after six months, respectively compared with the rest of fertilization treatments
IV Interactions effects:
Regarding to the interaction effect there was a significant interaction effect between irrigation tension as well as mineral and bio-fertilization in affecting averages of number of leaves per plant at 90 and 120 DAT, bulbing ratio at 120 DAT, RGR from 90 to 120 DAT and LWR from 90 to 120 DAT.
With respect to the interaction effect there were significant interactions effect between irrigation tension as well as mineral and bio-fertilization in affecting averages of bulb length (cm) and thickness of complete rings in 2007/2008 season.
There was a significant interaction effect between irrigation tension and mineral – bio-fertilizers affecting averages losses assessments percentage after 2 months in 2006/2007 season, losses assessments percentage after 4 months in 2006/2007 and 2007/2008 seasons, losses assessments percentage after 6 months in 2006/2007 season and total losses assessments percentage after 2+4+6 months in 2006/2007 and 2007/2008 seasons.
CONCLUSION
The results indicated that maximum marketable bulbs yield (t/fed), and the minimum total losses percentage in bulb yield are producing by irrigation at 24cb tensiometer reading (2328.38 m3/fed) and fertilization with 75% from recommended NPK i.e. 75 kg N + 30 kg P2O5 + 18 kg K2O/fed plus spraying 1000 ppm Amino Total at three times or spraying 4000 ppm Soft Guard at three times. Irrigation at 36cb tensiometer reading (1097.70 m3/fed) and reducing mineral fertilization (NPK) by 25% with spraying 4000 ppm Soft Guard or 1000 ppm Amino Total for three times maximized water use efficiency by 41.11% and reducing total losses percentage in bulb yield after six months by 39.12% compared with irrigation at 24cb tensiometer reading (2328.38 m3/ fed) and fertilization with 100% NPK as an average in both seasons.