Thursday 5 February 2015

Regular Farm Irrigation Assessments Pay-Off

The current soil moisture deficit conditions in many areas of New Zealand should prompt irrigators to assess the efficiency of their irrigation system and management practices. The information that this blog is beginning to build upon hopes to increase understanding and awareness of technologies so these improvements can be implemented.

What is yet to be defined is Irrigation System Efficiency, while you will find many variations in the wording of definitions in a nut-shell it is the ration of irrigation water available for plant growth to the total amount of irrigation water delivered to the farm. So 80% Irrigation System Efficiency means that 80% of the water delivered to the farm has been applied and stored in the crop root zone and therefore available for plant growth.

Recent roadside assessments of irrigation systems show there are some very simple irrigation management modifications that can be made with only the basic level of knowledge.

Irrigating the road = 0% irrigation efficiency as well as being a safety hazard. However much irrigation you put on the road it’s still not going to grow grass!

If your irrigator has an end gun control function then contact your irrigation dealer to find out how to program the end-gun to turn off at any point it is irrigating outside the boundary of the growing area. If your irrigator does not have an end-gun control function than you may consider a GPS End Gun Controller, for more info click here or contact your local Zimmatic Dealer.

Ensuring that the staff that are charged with managing your irrigation as well as those that occasionally help out are adequately trained is really important. If there is not the time or resources to carry out the training in-house there are courses run through IrrigationNZ and many online resources that are very helpful. Considering a guidance system for shifting K-line’s could resolve many issues and result in a significant increase in your irrigation efficiency.

Regular maintenance of your irrigation system can save wasted water as well as forgone growth from under-watering. As an example a blocked sprinkler near the end of a 500m centre-pivot could be causing ~5ha of your property to be under-watered. Many of these maintenance issues are easily identified provided staff are aware of what to look out for.

Limitations of irrigation infrastructure can be a constraint to improving your irrigation efficiency. As seen in the image above the irrigation water being applied within the ditch is not contributing to pasture growth, and is likely to cause wheel rutting and potentially a stuck pivot. Should your centre-pivot or linear-move irrigator run over non-productive areas, roads, tracks or water-ways then variable rate irrigation technology would allow you to avoid irrigating these areas. This not only will save you water and potentially energy costs but also prevent the other issues that arise.

Future blog posts will discuss variable rate irrigation technology in more detail and the many applications in addition to avoiding irrigating certain areas where the technology offers benefits.