الفهرس 
INRODUCTIONOnly 14 pages are availabe for public view
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Abstract
According to the constant and limited water resources in Egypt besides, the expected climate changes and the continuous increasing population, therefore water should be applied as a rare commonly. This can be achieved through a lot of procedures that can all lead to lesson water consumption by plant and maximize irrigation water productivity in turn, obtaining the best productivity from water. Computer simulation models have the potential to improve the efficiency of irrigation systems and thus deliver significant water savings. This can be achieved by optimizing the design and management decisions at the field level.
Egypt is the most productive country of date palm fruit in the world because of its nutritional, economic, and social importance to the Egyptians for thousands of years. Flood irrigation is popular irrigation method by the date palm growers because of its lower initial and running costs, easy to apply but it has lower water application efficiency, labor intensive and fully wetted area between trees, and not well suited for sandy soils. To improve the water application efficiency of surface irrigation methods, the use of gated pipes is the most efficient methods for conveying and distributing irrigation water over the entire field.
Field experiments were carried out in two successive seasons of 2018/2019 and 2019/2020 on date palm (phoenix dactylifera) at the Experimental Farm in El-Dakhla Distinct, New Valley Governorate, Egypt (latitude of 24° 32′ 44″ N and longitude of 27° 10′ 24″ E). Three techniques of gated pipe for surface irrigation system were used in this study: Two side furrows, basin and one side furrow with loop.
The objectives of this study:
1- Using simulation model to predict by appropriate advance and recession time, distribution uniformity and moisture distribution under root zoon for date palm under study area.
2- Rise of water distribution uniformity for surface irrigation system.
3- Improving the productivity of date palm under surface irrigation system.
4- . Maximizing water productivity for date palm using improved surface irrigation.
The methodology used can be summarized in the following:
a- Used gated pipe under different pressure head (0.3 -0.6 – 0.9 m) and measured discharge and pressure head at each gate.
b- Used gated pipe under three techniques of surface irrigation: (two side furrows, basin, and one side furrow with loop).
c- Using simulation models to predict appropriate discharge and pressure head, distribution uniformity, advance and recessions time for date palm under study area conditions.
d- Study the effect of using three techniques on determining the most appropriate advance time, recession time, and distribution uniformity along furrow irrigation.
e- Study the moisture distribution under the three techniques. Soil samples were taken to identify the moisture content in the soil profile ± (25 and 50 cm) (horizontal direction) around the trunk of the palm tree at depths of (10, 30, 60, and 90 cm) ( vertical direction).
f- Study the effect of using different techniques on yield of date palm under study area conditions.
g- Study the effect of using different techniques on determining the most appropriate quantities of the applied water to obtain higher water productivity.
The main results of this study could be summarized as follows:
1) By increasing the head from 0.3, to 0.6, and 0.9 m, the average gates discharge increased from 1.79, to 2.2, and 2.9 l/s, respectively.
2) Used G-Pipe simulation model to simulate gated pipes irrigation system under field conditions b using two different primary conditions of G-Pipe simulation model (input total outflow) 10.79, 13.7 and 17.97 l/s, or (input pressure head) after valve at the beginning of the pipeline 0.3, 0.6, and 0.9 m.
3) The high values of the coefficient of determination R2 and RMSE reflected a very good agreement between the model and observed values.
4) Data of validation for G-Pipe under gated pipe, gave a good indication of the model’s ability to predict and estimate outflow from gates.
5) The results were sufficiently acceptable to fulfill the objective of this work, this was confirmed by the good agreement between the simulated and measured advance time, recessions time.
6) Using WinSRFR simulation models to predict distribution uniformity under surface irrigation system for raising the water application efficiency leading to proper decisions.
7) Data revealed that the highest values of yield, water productivity and distribution uniformity were 12.288 Mg/fed, 2.1 kg/m3, and 90%, respectively for one side furrow with loop techniques comparing with two side furrow techniques 5.440 Mg/fed, 1.6 kg/m3, and 87%, respectively.
8) Data revealed that the lowest values of yield, water productivity and distribution uniformity were 5.760 Mg/fed, 0.8 kg/m3, and 68%, respectively for basin techniques.
The recommendations of this study:
from the previous, it could be recommended that using of simulation models can be a good tool to manage surface irrigation practice under Egyptian sand clay loam soil conditions.
Using G-Pipe and WinSRFR simulation models for predicting water distribution uniformity for gated pipes irrigation system is acceptable for furrow irrigation to maximize irrigation water productivity.