Irrigation.ppt

IRRIGATION
Irrigation is the artificial application of water to the
land or soil.
DRAINAGE
Irrigation is often studied together with drainage,
which is the natural or artificial removal of surface
and sub-surface water from a given area.
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USES OF IRRIGATION
 Growing of agricultural crops
 Maintenance of landscapes
 Re-vegetation of disturbed soils in dry areas and during
periods of inadequate rainfall
 Protecting plants against frost
 Suppressing weed growing in grain fields
 Preventing soil consolidation
 Dust suppression
 Disposal of sewage
 Mining 3

IRRIGATION SYSTEM
An irrigation system is more than application method
It includes;
 Source of water
 Management of water
 Conveyance of water
 Application of water
 Capture and reuse (Tail water Recovery)
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2
3
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1 Pressure flow to field
2 Sprinkler application
3 Runoff
4 Capture
5,6,7 Return flow
Field Source
Tailwater
Pond
IRRIGATION SYSTEM
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IRRIGATION SYSTEM
Surface Irrigation
Subsurface Irrigation
Sprinkler Irrigation
Micro Irrigation
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Water applied by gravity flow
 Basin Irrigation – Entire field is flooded
 Furrow Irrigation – Water fed into small channels
 Border Irrigation – Strips of land divided by low
dikes are flooded sequentially
SURFACE IRRIGATION
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BASIN IRRIGATION
Basins are flat areas of land, surrounded by low levees or
berms. The levees prevent the water from flowing to the
adjacent fields. Basin irrigation is commonly used for rice
grown on flat lands or in terraces on hillsides .
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FURROW IRRIGATION
Furrows are small, parallel channels, made to carry water in
order to irrigate the crop. The crop is usually grown on the
ridges between the furrows
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BORDER IRRIGATION
Borders are usually long, uniformly graded strips of land,
separated by earth bunds. In Contrast to basin irrigation
these bunds are not to contain the water for ponding but to
guide it as it flows down the field
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 Rice (grows best when its roots are submerged)
 Pastures, e.g. alfalfa, clover
 Trees, e.g. citrus, bananas
 Broadcasted crops, e.g., cereals (Basin and Border
Irrigation)
 Row crops (Furrow Irrigation)
 Not suited to crops which cannot stand in wet or
waterlogged conditions for periods longer than 24 hours
(root and tuber crops), e.g., potatoes, beets and carrots
SUITABLE CROPS
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 It is the simplest of all irrigation systems
 Low initial cost
 Low energy costs if gravity can be used to
supply the water
 Works well in odd shaped fields
ADVANTAGES OF SURFACE
IRRIGATION
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 High maintenance requirements
 Inefficient in water use
 Nutrients and pesticides are lost by deep
percolation below the root zone
 Not suitable for crops which grow below ground
such as potatoes, peanuts, sugar beets and
carrots.
DISADVANTAGES OF
SURFACE IRRIGATION
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Irrigation water is applied below the ground surface, thus
raising the water table to the crop root zone
Most crops are well suited for subsurface irrigation except
very deep rooted crops such as alfalfa and cotton.
SUBSURFACE IRRIGATION
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Works best on flat fields
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 Permits storage of water in the lower soil profile
 Reduces pumping costs
 Can be incorporated into an existing drainage
system with low additional cost
 Captures plant nutrients at or near the water
table for future use by plants
ADVANTAGES OF
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 Labor intensive to adjust elevation of weirs to
change from drainage mode to irrigation mode
and back again after heavy rains
 System cost can be high in soils with low
hydraulic conductivity or rolling topography
 Water quality must be high
DISADVANTAGES OF
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SPRINKLER IRRIGATION
 Water is applied similarly to natural rainfall
 Pumps supply water under pressure
 Water is distributed through a system of pipes to sprinkler heads
 Water breaks up into small water drops which fall to the ground
 Suitable crops include row crops, field crops, tree crops etc.
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 Frequent, low volume, low pressure application of water
 Drip Irrigation
 Suitable crops include orchards, windbreaks, vegetables etc.
MICRO IRRIGATION
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 The most efficient irrigation method
 Little runoff and evaporation occur
 Deep percolation is easily controlled
 Systems are easily automated to reduce labor costs
 Much of the surface remains dry, reducing weeds
 Low tension water availability enhances growth,
improves yield and quality
ADVANTAGES OF
MICRO IRRIGATION
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 Expensive to install and maintain
 A high level of management is required
 Clogging is a major problem
 Animals, especially rodents can damage plastic pipe
less than 4″ diameter
 Elevation differences can cause poor distribution
uniformity unless pressure regulators are used
DISADVANTAGES OF
MICRO IRRIGATION
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Irrigation.ppt

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Irrigation.ppt