Climate Change Adaptation - Climate Resilient Agriculture for Ensuring Food Security - page 240

Table 12.3 Farm irrigation effi ciencies for sprinkler
irrigation in different climates (the overall effi ciency
comprises conveyance effi ciency, fi eld canal effi ciency,
and fi eld application effi ciency) (FAO 1982 )
Climate/temperature

overhead by high-pressure sprinklers, sprays, or
guns mounted on risers or moving platforms.
Today a variety of sprinkler systems ranging from
simple hand-move to large self-propelled systems
are used worldwide. Use of sprinkler irrigation is
practiced in the Americas (13.3 million hectares
(Mha)), Europe (10.1 Mha), Asia (6.8 Mha),
Africa (1.9 Mha), and Oceania (0.9 Mha)
(Kulkarni et al. 2006 ).
A sprinkler irrigation system typically con-
sists of:
1. A pump unit which takes water from the
source and provides pressure for delivery into
the pipe system. The pump must be set to sup-
ply water at an adequate pressure so that the
water is applied at rate and volume adequate
to the crop and soil types.
2. Main pipes and secondary pipes which deliver
water from the pump to the laterals. In some
cases, these pipelines are permanently
installed on the soil surface or buried below
ground. In other cases, they are temporary and
can be moved from fi eld to fi eld. The main
pipe materials used include asbestos cement,
plastic, or aluminum alloy.
3. The laterals deliver water from the pipes to the
sprinklers. They can be permanent, but more
often they are portable and made of aluminum
alloy or plastic so that they can be moved
easily.
4. Sprinklers are water-emitting devices which
convert the water jet into droplets. The distri-
bution of sprinklers should be arranged so as
to wet the soil surface in the plot as evenly as
possible.
A wide range of sprinkler systems is available
for small- and large-scale application. Set sys-
tems operate with sprinklers in a fi xed position.
These sprinklers can be moved to water different
areas of the fi eld, either by hand or with machin-
ery. Hand-move systems are more labor intensive
and may be more suited where labor is available
and cheap. On the other hand, mechanically oper-
ated systems require a greater capital investment
in equipment. Mobile systems minimize labor
inputs by operating with motorized laterals or
sprinklers, which irrigate and move continuously
at the same time (Savva and Frenken 2002 ).

Farm irrigation effi ciency

Cool 0.80

Moderate 0.75

Hot 0.70

Desert 0.65

Sprinkler irrigation effi ciency is highly depen-
dent on climatic conditions. FAO ( 1982 ) pro-
posed the fi gures of farm irrigation effi ciencies
provided in Table 12.3 on the basis of climate.
Sprinkler irrigation technology can support
farmers to adapt to climate change by making
more effi cient use of their water supply. This is
particularly appropriate where there is (or is
expected to be) limited or irregular water supply
for agricultural use. The sprinkler technology
uses less water than irrigation by gravity and pro-
vides a more even application of water to the cul-
tivated plot. Additionally, sprinkler irrigation can
reduce the risk of crops freezing due to colder
than usual temperatures. More frequent and
intense frosts are already impacting on crops as a
result of climate change. During the night, the
motion of the sprinklers and the application of
rain-like water droplets can reduce the stress on
crops caused by a sharp decrease in temperature
(Snyder and Melo-Abreu 2005 ).

12.3.3.1 Advantages
One of the main advantages of the sprinkler irri-
gation technology is more effi cient use of water
for irrigation in agriculture. Sprinkler systems
eliminate water conveyance channels, thereby
reducing water loss. Water is also distributed
more evenly across crops helping to avoid wast-
age. The sprinkler irrigation system has also been
shown to increased crop yields (Table 12.4 ) and is
suited for most row, fi eld, and tree crops that are
grown closely together, such as cereals, pulses,
wheat, sugarcane, groundnut, cotton, vegetables,
fruits, fl owers, spices, and condiments and for
cultivating paddy crop (Kundu et al. 1998 ).
Sprinkler irrigation technology is well adapted
to a range of topographies and is suitable in all