Agriculture Reference
In-Depth Information
4.2.5.3 Ideal Condition for Evaluation of Irrigation System
The field (soil) and crop condition should represent the ideal/normal field condition
during the evaluation of an irrigation system. The conditions can be summarized as
follows:
(i) The field soil should be stable, not new, refilled or a developed one
(ii) The crop condition should be representative, not just after emergence or at
ripening stage but in between (good coverage)
(iii) The soil should be dry enough - appropriate time for irrigation
(iv) Water supply/water pressure should be sufficient enough to apply inflow in the
designed rate
4.2.6 Performance Evaluation Under Specific Irrigation System
4.2.6.1 Pumping Plant Evaluation
Pumping system efficiency can contribute substantially to energy saving. Pumping
plant evaluation requires a pump test, which checks the flow rate capacity, lift,
discharge pressure and/or velocity, rated discharge capacity, and input horsepower.
Pump discharge can be measured by flow meter, flume (at the vicinity of the
pump outlet) or by the coordinate method. Pump lift can be estimated by measuring
the depth to water table during non-pumping period using water-level indicator, or at
least by inserting a rope with load up to the water table and measuring the distance
with a tap. Rated discharge capacity of the pump can be read from the manufac-
turer's manual
or
the pump rating written on the pump body. If a mechanical engine
is used to power the pump, its capacity can be read from its rating seal or manual.
If an electrical motor is used to operate the pump, power consumption by the motor
can be measured by “Clip-On meter” or “Multi-meter” or from the change in power
reading in the “electric meter” for a certain period. Rated capacity of the motor can
be read from its body.
Knowing the above information, overall pumping plant efficiency and efficiency
of each component (such as motor or engine efficiency, pump efficiency) can be
calculated.
4.2.6.2 Border Irrigation Evaluation
Field observations and measurements required for conducting a border irrigation
system evaluation include the following:
•
Border dimension
•
Slope of the border
•
Inflow rate
•
Runoff rate and volume (if any)
•
Irrigation time (duration)
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