SPRINKLER IRRIGATION

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SPRINKLER IRRIGATION
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Sprinkler System Layout
sprinkler irrigation system Components are 1-
Pump unit. 2- Main line and sub-main lines. 3-
Laterals. 4- Sprinklers (impact type,
defector-plate-type).
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1- Permanent System
Types of Sprinkler Systems
2- Semi-permanent System

3- Portable System
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• pipes are permanently buried.

1- Permanent System

The main lines are buried in the ground, while
the laterals are portable.
2- Semi-permanent System
The mains as well as laterals are portable.

3- Portable System
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The Advantages of Sprinkler Irrigation

• 1-Seepage losses are completely eliminated.
  Moreover only optimum quantity of water is used
  in this method.
• 2- Land leveling is not required.
• 3- No cultivation area is lost for making
  ditches, as happens in surface irrigation
  methods. It, thus, results in increasing about
  16 of the crop area.

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• 4- In sprinkler system, the water is to be
  applied at a rat lesser than the infiltration
  capacity of the soil, and thus avoiding surface
  run off.
• 5- Fertilizers can be uniformly applied, because
  they are mixed with irrigation water itself.
• 6- This method leaches down salts and prevents
  water-logging or salinity.
• 7- It is less labor oriented and hence useful
  where labor is costly.
• 8- Up to 80 efficiency can be achieved, i.e. up
  to 80 of applied water can be stored in the root
  zone of plants.

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The Limitations of Sprinkler Irrigation

• 1- High winds may distort sprinkling pattern,
  causing non-uniform spreading of water on the
  crops.
• 2- In areas of high temperature and high wind
  velocity, considerable evaporation losses of
  water may take place.
• 3- They are not suited to crops requiring
  frequent and larger depths of irrigation.
• 4- Initial cost of the system is very high, and
  the system requires a high technical skill.
• 5- Only sand and silt free water can be used.
• 6- It requires larger electrical power.
• 7- Heavy soil with poor intake cannot be
  irrigated efficiently.
• 8- A constant water supply is needed for
  commercial use of equipment.

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Suitable Crops

• Most row, field and tree crops. However, large
  sprinklers are not recommended for irrigation of
  delicate crops such as lettuce because the large
  water drops produced by the sprinklers may damage
  the crop.

Suitable Slopes
Sprinkler irrigation is adaptable to any farmable
slope, whether uniform or undulating.
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Suitable Soils

• Sprinklers are best suited to sandy soils with
  high infiltration rates although they are
  adaptable to most soils.

Suitable Irrigation Water
A good clean supply of water, free of suspended
sediments, is required to avoid problems of
sprinkler nozzle blockage.
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Design of Sprinkler Irrigation Network

• 1- Selection of Sprinklers.
• 2- Design of the Laterals.
• 3- Design of the Sub-main Line.
• 4- Design of the Main Line.
• 5- Design of Pump.

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1- Selection of Sprinklers

• Qs Cda(2gh) 0.5
  
  
• Where
• Qs Sprinkler Capacity (m3/sec)
• Cd Discharge factor 0.8 - 0.95
• a Area of sprinkler (m2)
• g Acceleration due to gravity 9.81 m/sec2
• h Water pressure at sprinkler (m)
• By using the tables (1,2) sprinkler
  discharge can be determined.

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2- Design of Pump

• a- Total discharge No. of main linesmain line
  discharge
• b- Total pressure 1.1 design pressure of main
  line pump pressure (3m assumed)
• c- Pump capability (HP) and its electric energy
  (Pw) are determined from these equations
• HP (Q Htot ?) / (75 ?p)
• Pw (HP0.746) / (?E)
• Where HP Pump capability
  (horse)
• Q Discharge which is needed (m3/sec)
• Htot Total pressure (m) ? Specific
  weight (kg/ m3)
• ?p Actual efficiency of the pump (75 85)
• Pw Electric energy (kilowatt/hr)
• ?E Actual efficiency of the motor (85 95)

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TRICKLE IRRIGATION
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Trickle System Layout

• Trickle irrigation system
• Components are
• 1- Pump unit.
• 2- Control head.
• 3- Main lines, sub-main lines, and Laterals.
• 4- Emitters or Drippers .

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Trickle Irrigation
Trickle Irrigation for a Crop
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Advantages of Trickle Irrigation

• 1- A drip system produces healthy, fast-growing
  plants.
• 2- Drip watering keeps the moisture content of
  soil relatively constant and ensures that oxygen
  remains available to the root system.
• 3- Drip irrigation gives you the ability to put
  water exactly where its needed and keep paths
  and areas between plants dry. This reduces both
  waste and weeding.
• 4- Water lost to evaporation is negligible
  compared to overhead watering.
• 5- Drip can be designed for minimum runoff.

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• 6- You can deliver equal amounts of water to
  plants over a wide area.
• 7- A drip irrigation system is easy to install.
  Since no trenching is needed, you can install a
  system in an existing landscape with no damage to
  your plants root systems.
• 8- The greatest advantage for the home gardener
  is time savings. The simple action of opening a
  valve replaces all the time spent watering by
  hand. With the addition of an automatic timer,
  you can go on vacation or cope with a busy
  schedule while your garden flourishes without you.

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Disadvantages of Trickle Irrigation

• 1- The clogging of system components by
  particulate, chemical, and biological materials.
  Clogging can cause poor uniformity of application
  and if it continues long enough, can severely
  damage the crop.
• 2- Costs are, however, generally comparable to
  solid-set sprinkler system, but are higher than
  those of surface irrigation systems except when
  extensive land leveling is needed.
• 3- A salt accumulation problem can occur when
  only a portion of the root zone is wet and saline
  waters are being used for irrigation.

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Suitable Crops

• Drip irrigation is most suitable for row crops
  (vegetables, soft fruit), tree and vine crops
  where one or more emitters can be provided for
  each plant.

Suitable Slopes
Drip irrigation is adaptable to any farmable
slope. Normally the crop would be planted along
contour lines and the water supply pipes
(laterals) would be laid along the contour also.
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Suitable Soils

• Drip irrigation is suitable for most soils. On
  clay soils water must be applied slowly to avoid
  runoff. On sandy soils higher emitter discharge
  rates will be needed to ensure adequate lateral
  wetting of the soil.

Suitable Irrigation Water
One of the main problems with drip irrigation is
blockage of the emitters. All emitters have very
small waterways ranging from 0.2-2.0 mm in
diameter and these can become blocked if the
water is not clean. Thus it is essential for
irrigation water to be free of sediments. If this
is not so then filtration of the irrigation water
will be needed.
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Trickle System Layout

• Takes water from the source and provides the
  right pressure for delivery into the pipe system.

Pump Unit
Consists of valves to control the discharge and
pressure in the entire system. It may also have
filters to clear the water.
Control head
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Control head
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• Supply water from the control head into the
  fields.
• Made from PVC.

Main, sub-main lines and laterals
used to control the discharge of water from the
lateral to the plants. They are usually spaced
more than 1 meter apart with one or more emitters
used for a single plant such as a tree. For row
crops more closely spaced emitters may be used
Emitters or Drippers
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Main,sub-main lines and laterals
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Emitters or Drippers
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System Capacity

• Q (Aq / N se sl)
• Q the discharge of the pump (m3/sec),
• A area of the field (m2),
• q the discharge of emitter (m3/sec),
• N number of operational units,
• se the distance between emitters on laterals
  (m),
• sl the distance between laterals (m).

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Number of Operation Units

• N Hi / Ht
• Hi the time interval between two successive
  irrigations (day),
• Hi dw / Cu
• dw required water depth (mm),
• Cu consumptive use of the crop (mm/day),
• Ht the total time for operating the emitter
  (day), Ht dg se sl / q
• dg actual irrigation depth dw / irrigation
  efficiency

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Example 1

• Determine trickle system capacity for an area 125
  fed, if
• a- The system efficiency is 85,
• b- the distance between emitters on laterals
  0.6 m,
• c- the distance between laterals 1.2 m,
• d- the discharge of emitter 2 l/hr,
• e- required water depth 2.4 cm,
• f- consumptive use of the crop 6 mm/day,

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Solution Steps

• Q (Aq / N se sl)
• Q (125 4200 2 0.001) / (60 60 N 0.6
  1.2) 0.405 / N
• N Hi / Ht
• Hi dw / Cu 24 / 6 4 days
• Ht dg se sl / q (2410-3/0.85) 0.6
  1.2 / (20.001) 10.16 hr 0.423 days
• N 4 / 0.423 N 9.45
• N 8 (The emitter can make two movements in the
  day in one irrigation (4days))
• Q 0.405/8 0.051 m3/sec 51 l/sec.

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Thank you