|One of the key problems faced by the irrigation industry is water availability. Conversion from border-check to centre-pivot irrigation is a potential option to reduce water losses. Centre-pivot irrigators use low-pressure nozzles to irrigate large circular areas. They can be as short as a single-span 35 metre unit or as long as 800 metres with 18 or 20 towers, irrigating approximately 200 Ha. |
A well designed and well managed centre pivot should achieve an irrigation efficiency (IE) of 95%, where a well designed and well managed border-check irrigation system on appropriate soils should achieve 90%. On perennial pasture, this 5% difference corresponds to a water saving of about 0.5 ML/ha/year. (IE is the proportion of the applied water used by the crop.)
The improvement in irrigation efficiency associated with conversion from border-check to centre- pivot is likely to be greatest where an existing border-check system cannot capture and reuse surface run-off, or where deep drainage losses are high on light soils.
It is important to note that well managed border-check irrigation on appropriate soils can achieve better IE and productivity than poorly managed sprinkler irrigation. Thus, there are no hard and fast rules on what levels of water saving you should be able to achieve by converting to a centre-pivot irrigator.
A centre pivot may make better use of your water