CHAPTER IV IRRIGATION SYSTEM

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CHAPTER IVIRRIGATION SYSTEM
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The art of irrigation is very ancient and has
been essential for the development and blossoming
of some civilizations.
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• INTRODUCTION
• The art of irrigation is very ancient and has
  been essential for the development and blossom of
  some civilizations.
• II Kings 3l6-l7 of the Holy Bible alludes to the
  irrigation, in 2000 B.C. In the same year, queen
  of Assyria detoured the Nile River to irrigate
  the Egyptian desert.
• Irrigation is also mentioned in the old documents
  of Syria, Persia, India, China, Java and Italy.

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• INTRODUCTION
• The importance of the irrigation in our times has
  been defined accurately by N.D Gulati
• In many countries the irrigation is an old art,
  as much as the civilization, but for the humanity
  it is a science, the one to survive.

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• OBJECTIVES
• To provide the necessary moisture for the crop
  development.
• To ensure sufficient supply of water during
  droughts of short duration and unpredictable
  climate.

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OBJECTIVES

• To dissolve soil salts.
• It is a way to apply agrochemicals.
• To improve the ambient conditions for the
  vegetative growth.
• To activate certain chemical agents.
• To generate operational benefits.

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The hydrologic cycle.
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IRRIGATION METHODS

• Flood
• Furrow
• Infiltration
• Subsurface

• Sprinkler Overhead.
• Drip/Micro
• Hydroponics

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Selecting the Irrigation Method

• Crop Type
• Soil
• Water supply
• Climatologic conditions
• Availability and reliability of energy
• Available technology
• Economical and social considerations

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CAPACITIES AND LIMITTATIONS 1. Crop, soil
and topography. 2. Quantity and quality of
water. 3. Crop yields.
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CONSIDERATIONS OF MANUAL LABOR AND
ENERGY 1. Surface irrigation. 2. Sprinkler
irrigation. 3. Drip irrigation.
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Conditions for the selection of an irrigation
method
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Comparison of irrigation methods
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• SURFACE IRRIGATION
• The water runs on the soil surface providing
  necessary moisture to the plants for its
  development.

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SURFACE IRRIGATION

• The basic components are
• Water source
• Supply Lines
• Control mechanism
• Dams or dikes of control
• Furrows of irrigation
• Drainage system
• Reuse of irrigation water

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Surface Irrigation

• Flood Irrigation

Gated pipe irrigation system
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STRIP BORDER IRRIGATION

• The water is applied to a leveled area surrounded
  by ridges.
• Each irrigated area is completely at level
  without slopes in any direction.
• It is not necessary that the edges are not
  rectangular or straight nor that the ridges are
  permanent. 
• This technique is called leveled flood or
  irrigation by strip borders.

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FLOOD IRRIGATION

• It is a traditional system and is more commonly
  used in agriculture. One adapts to extensive
  planting methods. It is prone to diseases that
  are developed due to excess of soil moisture. 
• It uses surface (rivers, lakes, pools, etc.)
  water resource or a deep well. 
• This method requires that the fields are prepared
  with gentle slopes so that the water runs slowly
  by gravity and arrives at the lowest part of the
  farm, where it is collected by open channels for
  elimination or is recycled for use.

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STRIP IRRIGATION WITH DIKES

• The flood irrigation is most popular.
• It is used mainly in narrow row crops like rice.
• It can be defined as the application of water
  between parallel strips.
• The strip between adjacent dikes does not have
  slope in the transverse direction, but these have
  slopes in the direction of the irrigation.

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Figure 2(a) Periodic flood Irrigation
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Figure 2(b) Permanent flood Irrigation
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Figure 2(b) Simple flood Irrigation
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Figure 2(c) Multiple flood Irrigation
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Figure 2(d) Flood irrigation for crop in
terraces
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Figure 3(a) Simple ditches
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Figure 3(b) Double ditches
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FURROW IRRIGATION OR IRRIGATION BY
INFILTRATION

• The furrows are channels with slopes that are
  formed from the soil.   
• It is designed so that the water runs throughout
  the desired field. 
• The water under pressure arrives at the highest
  elevation of the field. It is distributed by
  channels or tubes, towards the fields where it
  will enter the furrows to flood the area. 

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FURROW IRRIGATION OR IRRIGATION BY
INFILTRATION

• From the supply lines, the water enters the
  furrows by means of floodgates, siphons or by
  opening a furrow.
• Water is applied when the channel is opened. One
  may use flood gates to control the application of
  water to a particular field.

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Figure 4(a) Simple furrows
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Figure 4(b) Multiple furrows
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Figure 4(c) Snail type furrows
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Figure 5(a) Circular sink furrows
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Figure 5(b) Square sink furrows
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Figure 6 Irrigation by surface infiltration

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FURROWS ALONG THE CONTOUR LINES 1. It
consists of small channels with continuous slope
and almost uniform by which the hilly areas are
irrigated. The furrows follow the contours lines
of the land.  2.This system can be used in uneven
lands, hilly areas, row crops and except for
sandy soils..
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LEVELED FURROWS

• The leveled furrows with no slopes are formed by
  a furrow opener and are used to irrigate crops
  seeded on the furrows or on the sides of furrows.
   
• This method requires a fast supply of water.
• The leveled furrows adapt better to soils with a
  moderate to slow index absorption and an index of
  retention capacity from medium to high. With the
  furrow irrigation, the best results are obtained
  in gentle and uniform slopes.

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FURROWS ON SLOPES

• These furrows consist of small channels with an
  uniform continuous slope in the direction of the
  irrigation. 
• This method can be used for the row crops,
  including vegetables. 
• The furrows with slopes can be used in all soils
  except sandy soils, with high degree of
  infiltration capacity and with a very little
  lateral distribution.
• This method must be used with extreme care in
  soils with high concentration of soluble salts.

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CORRUGATED FURROWS

• The system consists of a partial wrinkling of the
  soil surface.
• The irrigation water does not cover all the land,
  but is distributed in small channels or
  undulations at regular spaces.
• The water applied in the undulations infiltrates
  into the soil and extends laterally to irrigate
  the intermediate spaces between the furrows.
• The irrigation by undulations or corrugations
  adapts better to the drought areas and flat lands
  with slopes of l to 8.

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SPRINKLER IRRIGATION 1.The water is applied on
the soil surface in form of a rainfall.  2.The
spray pattern is obtained when the water at
pressure is expelled through small orifices.
3.The operating pressure is developed by an
appropriate pumping unit.
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TYPES OF SPRINKLER IRRIGATION SYSTEMS

• Manual operated and portable system.
• Lateral system on wheel (movable).
• Traveling sprinkler system with progressive
  movements.
• Central pivot system.
• Linear movement system.
• Low energy pressure system.
• Solid-set system.

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MANUALLY OPERATED AND PORTABLE SYSTEMS

• Include lateral pipe with sprinklers installed at
  regular intervals. 
• The risers are connected to the lateral tube. The
  length of the tube is selected to correspond with
  the desired spacing of the sprinklers. 

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MANUALLY OPERATED AND PORTABLE SYSTEMS

• The lateral pipe with sprinklers is placed on a
  ground surface. It is used until the application
  has been terminated.
• Then, the lateral tube is dismantled and is
  positioned in the next section. 
• This system has a low initial cost, but requires
  high manual labor. It can be used in almost all
  the crops. However it is difficult to move the
  lateral pipes, when the crop is mature.

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LATERAL SYSTEM ON WHEELS (MOVABLE)

• This system is a variation of the manual system.
• The lateral pipe is mounted on wheels.

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LATERAL SYSTEM ON WHEELS (MOVABLE)

• The height of the wheels is chosen so that the
  axis exceeds height of the crop for easy
  movement. 
• A drive unit is commonly a motor driven with
  gasoline and is located near the center of the
  lateral pipe.

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• TRAVELING SPRINKLER SYSTEM WITH PROGRESSIVE
  MOVEMENTS
• This system uses a spray (tube) gun of high
  pressure and high volume.
• The spray gun is mounted on a tow.
• The water is supplied by means of a flexible hose
  or from an open ditch.

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CENTER PIVOT SYSTEM

• It consists of a lateral pipe with simple
  sprinkler supported by a series of towers. 
• The towers car is impelled in such way so that
  the lateral pipe moves around the center about
  the pivot point. 

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LINEAR MOVEMENT SYSTEM

• The linear movement system is similar to the
  central pivot.
• The line of the pipe extends in perpendicular
  direction to the lateral one.
• The delivery of the water to the lateral is by a
  flexible hose or from an open ditch.  

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• LOW ENERGY PRESSURE SYSTEM (LEPA)
• LEPA systems are similar to the linear movement
  systems of irrigation. 
• The orifice in the lateral pipe and pipes can
  discharge at very low water pressure, exactly
  according to the soil moisture.

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SOLID-SET SYSTEM

• Here, the sufficient lateral pipes are placed in
  the field and are not moved during the season.
• The system of solid set is portable, with network
  of aluminum tubes for the irrigation.
• Enough lateral lines are used to cover all the
  area.
• The system reduces to a minimum the need of
  manual labor during the irrigation season.

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TYPES OF SPRINKLERS

• Rotating sprinkler, impact type These are more
  commonly used for wide variation of pressure,
  discharge, spacing and rate of application for
  different crops.

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TYPES OF SPRINKLERS

• Sprinkler type These are rotating sprinklers
  with a discharge up to 60 m3/h at a pressure head
  of 60 meters. It can cover areas up to one
  hectare simultaneously.

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TYPES OF SPRINKLERS

• Sprinklers with low flow rate These sprinklers
  apply l20 to 350 liters per hour at a pressure
  head of l5 to 25 meters. These are used mainly in
  irrigation of fruit or chards.

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TYPES OF SPRINKLERS

• Mini sprinklers These can apply 30 to l20 liters
  per hour at a pressure head of l5 to 25 meters.
  These are used in vegetables and nurseries.

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SUBSURFACE IRRIGATION

• In many areas, soil conditions and topography are
  favorable to the water below the ground surface.
• The favorable conditions are
• The existence of impermeable subsoil at a depth gt
  1.8 meters.
• Silt or silt-sandy permeable layer.
• Uniform topography and moderate slopes.

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• SUBSURFACE IRRIGATION
• ADAPTABILITY
• It is appropriate for uniformly textured soils
  with a good permeability so that the water is
  mobilized quickly, in a horizontal and vertically
  direction and to a recommendable depth under the
  root zone.

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• SUBSURFACE IRRIGATION CHARACTERISTICS
• This method is used in soils with low capacity.
• When the surface irrigation cannot be used and
  the cost of pressure irrigation system is
  excessive. 

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• SUBSURFACE IRRIGATION
• LIMITATIONS
• The water with high concentration of salts can
  not be used. In some arid regions, the soils can
  be salty.
• The selection of crops is limited. 
• The crops with deep root system (such as some
  citric) are not generally suitable for subsurface
  irrigation.

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• NATURAL SUBSURFACE IRRIGATION
• Geological and topographical conditions are
  favorable.
• It is adaptable for almost flat levels with deep
  surface layer and high lateral permeability. 
• At a depth of 2 to 7 meters from the soil
  surface, there is usually an impermeable rocky
  substratum.

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• DRIP IRRIGATION
• The application of water is by means of drippers
  of that are located at desired spacing on a
  lateral line. 
• The emitted water moves due to a unsaturated
  soil.  

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SUBSURFACE DRIP IRRIGATION (SDI)

• In this system, laterals with drippers are buried
  at about 45 cm depth.
• The purpose is to avoid the costs of
  transportation, installation and dismantling of
  the system at the end of a crop.
• When it is located permanently, it does not harm
  the crop and solve the problem of installation
  and annual or periodic movement of the laterals.
• A carefully installed system, it can last for
  about 10 years.  

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XYLEM IRRIGATION

• Xylem irrigation is the direct application of the
  water with necessary chemical agents into xylem
  of the trunk of a tree using a series of
  injectors depending on the age of the tree.
• Xylem irrigation is also called ultra micro,
  high frequency, tension, tree injection, or
  irrigation of chemotherapy. 
• There is no difference in the concept that these
  names represent. 
• The basic idea originated when several chemical
  products were injected within the vascular system
  of the plant. 

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HYDROPONICS SYSTEM

• The growth of plants without soil is known as
  hydroponics. 
• During l925-l935, an extensive work was done to
  modify the nutrient culture in the nurseries. In
  l930, W.F Gericke at University of California,
  defined hydroponics as a science to cultivate
  plants without the soil use, but using inert
  materials such as Sand, sawdust, among others.
• A nutrient solution with all the essential
  elements is added for a good development of the
  plants.

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SUMMARY

• The additional food need for the world population
  impose the fast development of the irrigated land
  throughout the world.

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SUMMARY

• Although, it is of vital importance for the arid
  regions, it is also necessary in the humid
  regions. In many regions of the world it is
  possible to irrigate with the water that is
  available.

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SUMMARY

• Less than half of the applied water is beneficial
  to the crop. That irrigation water is lost
  generally to the soil by erosion, deep
  percolation, alkali accumulation, and leaching.

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Figure 12 General components of a
hydroponics system
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new irrigation systems are being developed
to obtain the high efficiency of water
application