This course covers key irrigation management principles, introduces important terms, discusses ways to consider irrigation efficiency, and outlines on-farm irrigation system performance testing with emphasis on travelling irrigators typically used in vegetable production.
In broad terms what we are trying to achieve is maximum benefit (profitability) from irrigation, with minimum environmental impact. Irrigation uses about three quarters of allocated water in NZ and pressure on water resources is increasing. Power generation, recreation, ecological and other demands increasingly compete with irrigation for the available supply. In many places, water has been “over-allocated” and the amount users can take is being reduced. Ensuring your irrigation system is as efficient as possible allows best use of the water you have available.
Studies have shown irrigation efficiencies vary widely. There are two broad areas where irrigation efficiency improvements can be made. The first is system performance – how evenly water is distributed being among the most important. The second is how well the system is managed, in particular choosing the right amount to apply – are the taps turned on and off at the right time?
Improving efficiency saves water, energy and time. The savings can be very significant. Increasing uniformity from 0.7 to 0.9 can allow 50% more area to be irrigated from a certain volume of water. Using the right pump can chop 30% off a power bill.
Irrigation performance assessments allow us to check quality of design & installation, and that performance remains acceptable in later years. Farmers can check the performance of contract irrigators, and demonstrate efficient resource use to others: consumers, regulators and other resource users.
A useful guide to irrigation terminology is available from Irrigation New Zealand. Click here to see the “Irrigation Glossary”.
