Types of Irrigation System are discussed in this article. No one system is necessarily better than another. All can be made to work well, given the right situation and good management.
Successful irrigation depends on being able to apply the right quantity of water at the
right time as uniformly as possible across what may be a large area. As the scale of
production of orchard crops varies considerably – as well as the topography, soils and
the financial resources and skills available – so the methods of irrigation adopted vary.
They can broadly be classified into three categories: flood irrigation
sprinkler irrigation and trickle (or drip) irrigation In
addition there is a composite method known as bubbler irrigation.
Types of Irrigation System
Flood irrigation. This traditional irrigation category includes furrow and basin
irrigation, and also border strip (a less common method than the other two).
Furrow irrigation is commonly used in row crops, including orchards. Careful
grading of the soil surface is necessary to obtain relatively uniform distribution
of water across a field, with the water discharge rate matched to the slope and
length of the furrow and the infiltration rate of the soil. Deep seepage (unseen)
and excess runoff can lead to water wastage with the risk of waterlogging
and salinity. Furrow irrigation is practised on tree crops including bananas
(although the ratoon crops develop in different positions from the plant crop).
Basin irrigation (small, bunded, flat areas surrounding one or more adjacent trees)
is suitable for all tree crops, and is ideally suited for irrigating an individual
Sprinkler irrigation. Low pressure micro-sprinklers (under-tree) are very popular
in orchards. They were introduced in the 1960s, and are suitable for all tree crops;
they followed after the introduction of conventional sprinklers (these became popular
in the 1940s and 1950s). When mounted on high risers, sprinklers can also serve as
a method for frost protection (or other types of climate modification, such as
humidification, and cooling of fruit to encourage colour formation (anthocyanin),
as in apples (Figure 1.22)). High-pressure, mobile rain guns cover a large land area,
but the large droplets can damage the soil and the tree foliage; sprinklers on drag
lines are ideally suited for orchards; centre pivots need enough space and suitable
topography to operate effectively, but they can be automated.
Drip irrigation. First introduced to field and orchard crops in the late 1960s and 1970s,
this method of irrigation is now very popular in modern orchards (together with microsprinklers). It involves the precise application of water to the soil surface through a network
of plastic pipes and emitters, which can be above ground or buried (but it can then be
difficult to see if there have been any blockages). Drip irrigation has been used successfully
with many fruit crops, but it requires very good management to be fully effective.
Bubbler irrigation. This novel method of irrigation was developed in the USA during
the 1970s for use in orchards (Rawlins, 1977). Small basins around each tree are fed
from a low pressure, buried plastic drainage pipe water delivery system. The rate of
application and the amount of water to apply are controlled by the difference in
height between the top of the outlet pipe and a fixed, reference position. Bubbler
irrigation has been used to irrigate date palm and citrus