Chapter four discusses various irrigation application methods, including surface, furrow, border, and basin irrigation. It details their definitions, advantages, disadvantages, and key characteristics, with an emphasis on efficiency, water management, and soil types. Effective practices, common faults, and the limitations of each method are also highlighted.

1. CHAPTER Four : IRRIGATION APPLICATION METHODS
Irrigation Application Methods
Surface Irrigation Pressurized Irrigation
Basin Irrigation
Furrow Irrigation
Border Irrigation Trickle Irrigation
Sprinkler Irrigation

2. surface irrigation
• Definition
• Surface irrigation has evolved into an extensive array of
configurations which can be broadly classified as:
• (1) basin irrigation;
• (2) border irrigation;
• (3) furrow irrigation;
Introduction con

3. Introduction cont…
• There are two features that distinguish a surface irrigation
system:
• (a) the flow has a free surface responding to the gravitational
gradient;
• (b) the on-field means of conveyance and distribution is the field
surface itself.

4. General characteristics of Surface Irrigation:
• Old-age method
• the most extensively used method worldwide
• water application is directly on the soil surface
• Requires relatively minimal capital investment
• doesn’t require complicated and expensive equipment
• Energy costs are substantially lower

5. • Labor requirements is relatively high
• Relatively inefficient method
• Limited to land already having small and even slopes
• entirely practiced where water is abundant.
• More affected by water logging and salinity problems
• Land leveling costs are high

6. Good Surface Irrigation practice:
 distribution of water evenly in the soil,
 adequate water supply for the crops and
 avoidance of undue water wastage
Water movement problem in surface irrigation:
 Uneven water distribution (not uniform): due to contact time
difference between the head and tail end of the field.
 Percolation loss: due to large contact time or greater
infiltration near the head of the field.
 Runoff loss: due to continuous supply of water after the
water has reached the tail end of the field.

7. Furrow Irrigation
Definition:
• Furrow irrigation is the most widely used method worldwide for
irrigating row crops.
• In furrow irrigation, water no longer flows over the entire soil
surface but is confined to small channels (furrows) between the
crop rows.
• It is then gradually absorbed into the bottom and sides of the
furrow to wet the soil.
Furrow irrigation avoids flooding the entire field surface by
channelling the flow along the primary direction of the field
Water infiltrates through the wetted perimeter and spreads vertically
and horizontally to refill the soil reservoir.

8. Furrow Irrigation cont…
• Furrows provide better on-farm water management flexibility under
many surface irrigation conditions.
• The discharge per unit width of the field is substantially reduced and
topographical variations can be more severe.
• A smaller wetted area reduces evaporation losses.
• Furrows provide the irrigator more opportunity to manage irrigations
toward higher efficiencies as field conditions change for each irrigation
throughout a season.
• This is not to say, however, that furrow irrigation enjoys higher
application efficiencies than borders and basins.

9. Furrow Irrigation cont…
• There are several disadvantages with furrow irrigation. These may
include:
1. an accumulation of salinity between furrows;
2. the difficulty of moving farm equipment across the furrows;
3. the added expense and time to make extra tillage practice (furrow
construction);
4. an increase in the erosive potential of the flow;
5. a higher commitment of labor to operate efficiently; and
6. generally furrow systems are more difficult to automate, particularly
with regard to regulating an equal discharge in each furrow.

10. Furrow irrigation
Shape of furrow:
• Furrows are usually V-shaped, parabolic etc.
• Width of furrow: 250-400mm
• Depth of furrow: 150 – 300mm.

11. Fig.1 Typical Furrow Irrigation System

12. Figure 7: Short and long furrow at farmer’s field

13. • There are different ways of applying water to the furrow from
the head ditch.
– Using Siphons
– by cutting the ridge or levee separating the head ditch and
the furrows
– Using spill (short pipes) buried in the ridge

14. Fig. 2 Furrow Irrigation by Cutting the Ridge

15. Fig.3 Furrow Irrigation by Siphons

16. Furrow Spacing: depends on
• Water movement in the soil
– E.g. close furrows on sandy soils
• Crop
– E.g. double rows for onions
• Cultivation Practice
– E.g. equipments used for cultivation and harvesting
Furrow length:
• It depends on soil type, stream size, irrigation depth, field size and
shape, slope, farming practice.

17. • But generally,
• Furrows can usually be longer on clay soils than on sandy soils.
• Furrows can be longer when a larger stream size is used for irrigation.
• Furrows can be longer when a larger irrigation depth is applied.
• Furrows are usually shorter on steeper sloping land to prevent erosion.
Furrow Slope:
• Ideally furrows should have a uniform slope.
• A minimum slope of 0.05% is needed to ensure that water will flow
down the furrow and any excess water can be drained.
• The maximum slope depends on the risk of soil erosion.

18. Crops:
• Most row crops such as vegetables, cotton, sugar beet and
potatoes
• The crops are usually planted on raised bed or ridges
Irrigating furrows:
• When irrigating furrows, water is supplied to each furrow from the
farm channel using siphons or spills.
• Several furrows can be irrigated at the same time depending up
on the discharge available in the farm channel.
• The stream size must be large enough for the flow to advance
quickly down the furrow.
• Runoff can be a major problem in furrow irrigation.

19. Common faults in furrow irrigation:
a) Poor land preparation
• Uneven slope and low areas in a field can result in poor water
distribution and water logging.
b) Different soil types along furrow
• It is very similar to that for basins and borders. If the soil varies in
texture along the furrow, water distribution will be very uneven.
c) Advance time too long
• This is usually the result of using a stream size which is too small, long
furrow, sandy soils.
d) Stopping inflow too soon
• If the stream is cut off too soon, it results in a poor distribution of
water, and plants at the end of furrows do not get enough water.
Irrigation Efficiency
• On well managed furrows, the irrigation efficiency can be as high as
90%.

20. Border Irrigation
Definition:
• Here, the land is divided into strips (border) by parallel small
earth bunds called border ridges.
• In a border irrigation, each strip is irrigated separately by
introducing water upstream and it progressively covers the entire
strip.
• Water is applied to individual borders from small hand-dug
checks from the field head ditch.
• When the water is shut off, it recedes from the upper end to the
lower end.

21. Border Irrigation cont…
• Borders are different from basins into two important
differences:
– Borders slope uniformly away from the farm channel.
– A uniform distribution of water is obtained by using a small
stream size.
Size and shape of Borders:
• Borders are often long and narrow
• They are usually rectangular in shape varying in size from 100 –
800m long and 3 – 30m wide.

22. Border Irrigation System

23. Border Irrigation cont…

24.  Border cont…
 Size and shape of borders depends on soil type, stream size,
irrigation depth, slope, field size. Generally,
 Borders are much longer on clay soils than on sandy soils.
 Borders are longer when a larger unit stream size is available.
 Borders are longer when a larger irrigation depth is applied.
 Borders must be shorter on steeper sloping land to prevent
erosion.
 Borders can be wider when larger stream sizes are available.

25. Crop:
 Sloping borders are suitable for nearly any crop except those
that require prolonged ponding.
 Border irrigation is suited for crops that can withstand
flooding for a short time e.g. wheat.
 It can be used for all crops provided that the system is
designed to provide the needed water control for irrigation of
crops.
Soil:
 Soils can be efficiently irrigated which have moderately low to
moderately high intake rates but, as with basins, should not
form dense crusts unless provisions are made to furrow or
construct raised borders for the crops.

26. Border Irrigation cont…
• It is suited to soils between extremely high and very low
infiltration rates.
Land Slope:
• Ideally, borders should have a uniform slope along the length and
no cross slope.
• The precision of the field topography is also critical, but the
extended lengths permit better leveling through the use of farm
machinery.

27.  The minimum slope along the length of border is usually
0.1% to ensure water flow down the border.
 The maximum slope depends on the risk of soil erosion
Irrigating borders:
 When irrigating borders, it is important to use the right unit
stream size for the soil and land slope, and to stop the flow at
the right time .
 The stream size per unit width must be large, particularly
following a major tillage operation, although not so large for
basins owing to the effects of slope.

28. Common Faults in Border Irrigation Practice:
i) Poor land preparation
• When a border slopes unevenly, the flow down the border is also
uneven.
ii) Different soil types along border
• The effect is very similar to that in basins. Water distribution can
be very uneven.
iii) Using wrong stream size
• Too much water application usually means that the stream size is
too small. And, it results in high percolation loss.
• Too little water application usually means that the stream size is
too large. And, it results in high runoff loss.

29. iv) Fixed irrigation schedule
• Although the right stream size is used, some irrigators choose the
irrigation time to fit with other farm work rather than on the
irrigation needed.
v) Irrigation Efficiency
• On well managed borders the irrigation efficiency can be as high
as 80%.

30. Basin Irrigation
Definition:
• It is the simplest of all methods of irrigation.
• It involves dividing the field into a number of small strips of land
called basins.
• Each basin is a level area of land surrounded by earth bunds in
which water can be pounded until it infiltrates in to the soil.
• If a field is level in all directions, is encompassed by a dyke to
prevent runoff, and provides an undirected flow of water onto the
field, it is herein called a basin.
• A basin is typically square in shape but exists in all sorts of
irregular and rectangular configurations.

31. Basin Irrigation cont…
Size of Basins:
It depends on soil type, stream size, irrigation depth, field size, etc.
But generally,
– Basins are much larger on clay soils than on sandy
– Basins can be larger when a large stream size is used.
– Basins can be larger when a larger irrigation depth is used,

32. Basin Irrigation cont…
• There are few crops and soils not amenable to basin irrigation,
but it is generally favored by moderate to slow intake soils, deep-
rooted and closely spaced crops.
• Crops which are sensitive to flooding and soils which form a hard
crust following an irrigation can be basin irrigated by adding
furrowing or using raised bed planting.
• Reclamation of salt-affected soils is easily accomplished with
basin irrigation and provision for drainage of surface runoff is
unnecessary.
• It is always possible to encounter a heavy rainfall or mistake the
cut-off time thereby having too much water in the basin.
• Consequently, some means of emergency surface drainage is
good design practice.

33. Basin Irrigation cont…
• Basins can be served with less command area and field
watercourses than can border and furrow systems because their
level nature allows water applications from anywhere along the
basin perimeter. Automation is easily applied.

34. Figure 5: Basin method of irrigation

35. Land slope for basin:
• The soil surface within each basin must be level.
• On sloping and undulating ground the land surface must be re-
shaped into level areas.
Crops grown :
• Rice is the most common crop irrigated by basin.
• Other crops: alfalfa, maize, ground-nut, fruits
Irrigating basins:
• When irrigating basins, the stream size must be large enough
for the flow to advance rapidly across the basins. This will
ensure a reasonably uniform irrigation.
• A practical guide line to irrigate basin is to use a stream size
large enough for the flow to reach the far end in one quarter of
the contact time. This is called the quarter time rule.

36. Common Faults in Basin Irrigation Practice:
i) Poor land preparation
• When a basin is constructed on sloping ground and the land is not
leveled, too much water at the lower end.
• If a basin is constructed on reasonably level ground but the land
has not been leveled properly, more water on the lower spots and
less water at the higher.
ii) Basins covering more than one soil type
• Variations in soil type within a basin can result in water infiltrating
much faster in one place than in another.
iii) Irrigation efficiency
• On well managed basins irrigation efficiency can be as high as 90%.

37. Limitations
• Soil crusting
• Not suited to crops that cannot accommodate inundation.
• Precision land leveling is very important to achieve high
uniformities and efficiencies.
• Many basins are so small that precision equipment cannot work
effectively.
• The perimeter dykes need to be well maintained to eliminate
breaching and waste, and must be higher for basins than other
surface irrigation methods.

38. Limitations cont…
• To reach maximum levels of efficiency, the flow per unit width
must be as high as possible without causing erosion of the soil.
• When an irrigation project has been designed for either small
basins or furrows and borders, the capacity of control and outlet
structures may not be large enough to improve basins.

39. The three typical cases of surface irrigation practices are:
A) the inflow is cutoff shortly after completion of the advance
phase and application inadequate at some point in the field.
B) the least watered area just receives the required depths
C) the applied depths exceed the requirement at all locations
(the usual case)
Three typical cases of surface irrigation practice: