الفهرس 
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Abstract
Egypt today faces many challenges due to lack of water, the rapid increase in population and growth, climatic changes, it made us turn to modern agriculture without soil, especially aeroponics systems, which provide the amount of water used for irrigation, land area and give greater productivity.
In this study we try to find solutions ”to the problems of water shortages using aeroponics.
The objectives of this study:
1. Study the effect of some engineering factors of irrigation systems in aeroponics.
2. Study of water distribution uniformity inside the system.
3. Calculation of crop water use efficiency for lettuce type Lollo Rosso and celery.
4. The effect of sunlight on productivity.
5. Total cost of the square meter unit.
The Experiment was carried out in the Central Laboratory for Agricultural Climate, Agricultural Research Center, Dokki, Giza – Egypt from 5/4/2016 to 5/5/2016 to study some engineering factors affecting irrigation system in aeroponics.
Three types were selected from different spray nozzles (mini-sprinkler, micro-sprinkler and spray rotor) at operating pressure of (0.25 bar - 1 bar).
Systems have been developed on three different distances (50 cm* 50 cm, 75 cm* 75 cm and 100cm* 100 cm).
The best results were as follows:
The best results were obtained at a distance of 100 cm, micro-sprinkler under pressure (0.25 bar)
The discharge was 14 liters/hour and 89.7% distribution order where It gave the highest productivity of the lettuce and celery, respectively (9.5, 10.5) kg / column / cycle.
Water use efficiency was calculated for lettuce and celery and it was as follows 9.45, 8.4 kg/m3, respectively.
Finally, the total cost was calculated in the aeroponics system for meter square and it was 216.4 l/m²/year.
Aeroponics is the process of growing plants in an air or mist environment without using soil or an aggregate medium.
This study was to elevate, the water use efficiency of the aeroponics system throughout the water distribution uniformity inside the system as well as increase the crop yield and its quality through an examination of some engineering factors of aeroponics system, sunlight on lettuce and celery and different spacing between agricultural vertical colum.
• Results showed the following:
• The highest production of lettuce and celery was at 100 cm spacing between columns, where the total productivity for lettuce and celery was as follows: 9.5kg / colum /cycle and 10.5 kg / colum /cycle, respectively with better distribution of sunlight at 1200 lux.
• Sunlight effects on productivity was obvious at the top of column, where the total vegetative lengths for lettuce and celery were 22.8 and 42 cm, respectively. Lengths of total root of lettuce and celery were 7.4 cm and 8.8 cm, respectively.
• Water use efficiency for lettuce and celery was 59.37 kg/m3 and 55.26 kg/m3/cycle, respectively.
• Aeroponic system gave ahigher production than the deep water system, where production of lettuce and celery in aeroponics system, was 9.5 kg/m2 and 10.5kg/m2, respectively, and deep water system for lettuce and celery it was 7.5 kg/m2 and 9.6 kg/m2,cycle, respectively.