الفهرس 
Water resources in EgyptOnly 14 pages are availabe for public view
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Abstract
Due to the limited and the stability of Egypt’s water resources, and
climate change, population growth, which requires the provision amounts of
irrigation water, so you must adjust the amount of water and the quantities of
fertilizers used in agriculture, through the use of irrigation automated systems
and identify water and fertilizer amounts by scheduling mechanism for the
provision of quantities of water horizontal expansion, as well as reduce deep
percolation.
It is known that in a drip irrigation system is a direct correlation or
positive relationship between the operating pressure and the emitter flow rate.
This relationship may be affected by some changes in the physical properties
of water, one of these changes is to increase the proportion of salt, which are
usually found in low-quality water where salt degrees vary with water
depending on the purpose, which was used the water by, or that the source is
the sea salt.
This study aimed to:
1) Laboratory experiment studied the influence of different water salinity
on the performance of five emitter types.
2) Study the influence of various operation pressures on the performance of
selected emitters.
3) Recommend the three better of the emitter types to be applied in the
field.
4) Study the influence of water salinity on the hydraulic characteristics of
emitters.
5) Evaluate the effect of water salinity and emitter type on the growth and
yield of turnip crop.
Laboratory hydraulic experiment was carried out at water Relations and
Field Irrigation Dept., (NRC) to evaluate hydraulic performance for five
emitter types and selected the best to applied in the field experiment, whichapplied in Research and Research and Production Station, NRC, Nubaria, ElBeheara Governorate, Egypt, 2015/2016 season to study the effect of the
selected emitters types under different irrigation water salinity on the
hydraulic properties of the drip irrigation system, plant growth characters and
yield of turnip crop.
Lab experiments were conducted to evaluate hydraulic parameters for
five emitter types [On-line emitter NEIN-ETF (NPC1), Built in GR (NPC2),
pressure compensating emitters NEIN-PC (PC), Pressure compensating and
Self-flushing emitter EDEN-PC (PCS)and On-line Commercial Katif emitter
KATIF-R-P-201 (NPC3)] under water salinity (345, 2000, 4000, 6000; 8000
ppm) and different operation pressure heads (0.8, 1.0, 1.2, 1.4,1.6, 1.8; 2 bar).
While in field experiment which was carried out to study the effect of some
selected emitters (NPC1, NPC2, and, NPC3) under different water salinity,
(2000 and 4000 ppm in addition to the canal water, 345 ppm) on the plant
growth characters and yield of turnip (Brassica rapa L).
The obtained results as follows:
There is a positive relationship between the operating pressure and the
emitter flow rate. Regarding the effect of operation pressure on the flow rate
of the different studied emitters (NPC1, NPC2, PC, PCS, and NPC3), one can
notice that increasing operation pressure associated with the increasing
emitters flow rate. It is worth to mention that the rate of increase flow rate as
affected by operation pressure were 4- 9- 14, 3- 5- 8 and 3, 5, 9 % in same
sequences, if we compare the emitter flow rate at 1, 1.2; 1.4 bar comparing
with 0.8 bar.
The effect of emitter type on the coefficient of variation (CV) under (1.0
bar) as a nominal pressure head, one can notice that for, the ranked of emitter
type were NPC1>NPC3>NPC2>PC>PCS.
Emitters PCS and PC were the worthy ones that dramatically decreases
their flow rate with increasing water salinity. from the other side, NPC1and
NPC3 were the most suitable and moderately affected by water salinity
followed by NPC2.It was observed that NPC1 followed by NPC2 and lastly NPC3 were not
affected strongly by increasing water salinity.
Water movement and distribution pattern differ regarding the irrigation
method, especially under drip irrigation compared with other surface
irrigation method. Under drip irrigation, in addition to its high application
frequency, water is applied at separated points on the surface of the soil
rather than over the total area, so the soil is wetted in a cone shape like
axially symmetric pattern rather than in one-dimensional fashion.
With low flow rate, water moves in a vertical direction that results in
higher moisture adjacent to the emitter location. The wetting patterns under
the emitters are characterized by the depth of wetting front under emitter and
the radial wetting front at the surface.
Under irrigation with saline water (2000 and 4000 ppm) resulted in
relatively low salinity levels in the area extending downward from the emitter
and larger salt accumulation in the areas among emitter and close to the front
of the bed for the investigated soil.The low salinity water extended further
horizontally in the soil profile, while it is flat and moderately flat relative to
the moisture content in different soil layers before irrigation.
According to AE% values, there were no significant differences among
the tested emitters. Regarding AE% for NPC1 emitter, it recorded the highest
value (91.74 %), while NPC3 counted the lowest AE% (90.94).
Water amount applied to the crop during the growth season varied
from 1824 m3/fed to 1907 m3/fed at operation pressure 1 bar.Comparing
WUE for examined emitters, NPC1 had a primitive effect and recorded 14.5
and 17.4 % more thanNPC2 and NPC3 respectively.
The impact of the investigated two parameters (water salinity and
emitter’s types) had a promise value or accepted trend. DU values were more
constant under different emitters and there was no high difference within
salinity treatment of each emitter. The highest and lowest values of DU at 1.0
bar were recorded at (345 ppm) and the lowest one was recorded at 2000 ppm
followed by 4000 ppm.According to water use efficiency as affected by water salinity and
emitter’s type of turnip crops, it’s clear that NPC1 emitter recorded the
highest value which ranged from 18.12 ton/fed (4000 ppm) and 23.43ton/fed
(354 ppm) and 12.8; 9.1 kg/m3for 345 and 4000 ppm, respectively at 1 bar
operation pressure. While comparing WUE for examined emitters, NPC1
recorded 14.5 and 17.4 % more thanNPC2 and NPC3 respectively.