الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
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Abstract
The study aim to evaluate subsurface trickle irrigation system as
related to emitter discharge and infiltration soil when the discharge of a
subsurface emitter becomes larger than the soil infiltration intake creating
back pressure from soil on emitter flow. One goal of the study is to assess
the performance of subsurface trickle irrigation SSDI comparing with
surface trickle irrigation SDI.
To achieve this objectives
1- Measured emitter flow rates and their correspondent pressure head
along trickle lateral at selected emitter outlets of both SSDI and
SDI for 2, 4, 8 and 16 l/h emitter flow rate at 100 and 150 kPa inlet
pressures
2- Tested the emitters in terms of manufacturing and hydraulic
variations for SSDI and SDI.
A field experiment was conducted for 50 m of lateral length (φ13.6 mm
inner diameter), and with 100 turbulent flow path emitters which
connected to lateral by connector between them micro-tube φ4 mm inner
diameter in zero slope level. In addition, emitter spacing was 0.5 m, and
the inlet pressures head were 100 and 150 kPa. Several points were taken
into consideration, such as emitter characteristic friction loss,
manufacturing variation, flow rate and hydraulic variation. A comparison
study between the flow rates of emitters in surface trickle irrigation (SDI)
and other subsurface trickle irrigation (SSDI) in which emitters were
buried at 20 cm from soil surface. For given initial soil moisture content
and emitter flow rate, soil wetted area under the emitter for clay and
sandy clay loam soils with two different hydraulic properties were
plotted. Results showed that pressure head and flow variation along
lateral decreased by increasing both emitter flow rate and inlet pressure.
A higher soil back pressure is developed where the emitter flow is high.
The values of irrigation uniformity of subsurface trickle irrigation were
greater than it’s values in the case of surface trickle. Flow variation along
lateral increased in surface trickle lateral than subsurface trickle lateral.
Also field results showed that horizontal and vertical water movements
were related to both emitter flow rate and soil intake rates. Soil moisture
content was contoured directly after irrigation and soil-water
redistribution.