Information Sheet
IS14019
Irrigation scheduling – what does it mean?
The aim of irrigation scheduling is to apply the right amount of
water, in the right place at the right time to achieve optimum
yields.
A range of tools and scheduling methods are available.
These range from simple tools such as mini pans, to more
sophisticated tools like tensiometers and capacitance probes
and finally to crop models.
Overhead irrigation
With overhead irrigation where the application amount can
be more accurately managed, irrigation scheduling can be
improved by using evapotranspiration and crop factors to more
closely match applications to water use.
The type of irrigation system and degree of accuracy required
will influence the choice of scheduling tool.
Furrow irrigation
For furrow irrigation where the volume of water applied is
difficult to manipulate, the main focus is usually on when
to irrigate rather than the amount of water to apply. In this
situation mini pans, tensiometers and capacitance probes are
suitable tools. The problem with these tools is that it can be
difficult to schedule more than a couple of days out.
If the water holding capacity of the soil is known,
evapotranspiration and crop factors can be used to calculate
the crop water use. As long as weather conditions are
reasonably stable it is possible to estimate when the crop will
next require irrigating.
Drip irrigation
Drip irrigation requires a high degree of precision to match the
amount of water applied to the crop use on a daily basis. Crop
models that use real time weather data to ‘grow’ the crop and
calculate daily water use are the best option.
More information
For more information on scheduling tools and methods see the
following Information Sheets:
• Calibrating irrigation scheduling tools IS13024
• Crop water use IS13023
• Irrigation scheduling tools – capacitance probes IS13027
• Irrigation scheduling tools IS13025
• Irrigation scheduling with mini pans IS13022
• Simple calculations for furrow irrigation IS13026
• Soil water holding capacity IS13107
• Tensiometers IS13109.
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