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Making it work . . . Kate and Nick Webster's sustainable use of irrigation has been recognised at Australasian level. PHOTO: SUPPLIED

North Otago has produced two of the eight finalists in an Australasian sustainable agriculture competition.

Farmers Nick and Kate Webster and Brock and Gemma Hamilton have been shortlisted from a slew of entrants on both sides of the Tasman for the Zimmatic Sustainable Irrigation Awards.

The contest aims to celebrate irrigation excellence and encourage farmers to share water management ideas.

The Websters run Totara Fields and Hillbrook Dairies – mixed beef finishing/cropping and dairy operations on a total of 700ha, 550 of them irrigated.

They have four centre pivots, five hard-hose guns, and K-Line on the rolling contours.

All the pivots are controlled by variable rate irrigation (VRI), Mr Webster said.

“You definitely wouldn’t be without it,” he said of the system in which a computer regulates each sprinkler to place exact amounts of water only where it is needed.

He had not yet calculated whether it had paid for itself, but there were environmental and day-to-day ease-of-operation benefits as well as the financial aspects.

Mr Webster is a fan of the “bucket test” recommended by Irrigation New Zealand, which involves placing buckets under the sprinklers to ensure they deliver the correct amount of water and at the correct rate.

Not only did that help compliance with the North Otago Irrigation Company’s compulsory farm environment plan, but it also gave farmers confidence they were getting it right, he said.

“From an irrigation perspective, everyone is trying to tailor it to be as efficient as possible.”

Not everyone could afford to install a gold-standard system at the outset, Mr Webster said. It cost $10,000 to $12,000 per hectare for centre pivot irrigation and $2000 to $3000 for K-line.

But it was wise when setting up a system to allow for future add-ons, he said.

“You keep chipping away at it. You’re always learning.”

It was great to “rub shoulders” with innovators in the sector and to know IrrigationNZ was fighting for changes at the policy level.

Mr Webster said he and his wife were lucky to be able to promote water and the benefits of its efficient, sustainable management to their peers.

“I believe that our generation of farmers, particularly in North Otago, are fortunate to have the opportunity to farm with reliable water.

“The irrigation schemes we now draw water from were largely implemented by farmers involved in devastating droughts. It’s our role to utilise this resource as efficiently as we can, while continuing to develop and grow as an industry.”

Future-proofing . . . Brock and Gemma Hamilton, with their children (from left) Tate (5), Cooper (3), and Quinn (1), ensure their irrigation use is as environmentally-friendly as possible. PHOTO: SUPPLIED

Brock and Gemma Hamilton farm Avon Glen, a 375ha dairy property that includes 250ha under irrigation.

They bought their farm as a dryland property. When the North Otago Irrigation Company expanded its scheme eight years ago, they were able to access water and converted to dairying.

They now have 150ha under a centre pivot, 60ha with fixed grid irrigation, 50ha of K-Line and 15ha watered with a hard-hosed gun.

“We have designed our irrigation system to use the most effective/efficient application for the land type and area,” they said.

“With the NOIC irrigation scheme, the maximum instantaneous rate of water that can be taken is 0.4 litres per second. This means we have had to set up different application rates for various irrigation to ensure we can still use our full flow while we have our other areas turned off for grazing.

“We aim to use all our allocated water as much as possible to manage deficits in the summer.

“We have the ability to spread some water on to our dryland blocks if the dairy farm is getting enough water. However, in summer, 0.4 L/s is not enough to keep up with evaporation.

“Where possible we have used pivots (a total of eight) irrigating 150ha. Pivots have the most future potential to improve water efficiency by allowing us to use VRI for cropping areas and our lanes. We will be able to use unutilised water elsewhere on our platform.”

The Hamiltons said the fixed grid irrigation installed on the hills meant they could adjust application rates, using less on lower parts of gullies to decrease runoff.

“We can be more particular with application rates to benefit sensitive areas.

“Our fixed grid irrigation is controlled by radio so we can manage each pod individually.”

Pods in wetter areas were used less often.

“We use a Qtech data system. This is helpful from a performance and maintenance point of view, as we are notified if a pod is not responding, know battery and radio health, and manage performance to act accordingly.

“We do weekly moisture metre testing to show trends for system management. We are able to make decisions regarding altering irrigation for sustainable, efficient use.

“We bucket test annually to ensure our application rate is accurate. SPACE pasture reports allow us to know our pasture growth.

“We are trialling new drone technology where we can implement computer systems paired with visual analysis of images to see where application rates need to be adjusted. This too provides us valuable information about pivot health by indicating blocked sprinklers, etc.”

Mr and Mrs Hamilton planned to refine their application rates further in the future by putting VRI on some pivots and continuing to update their fixed pod programme as areas became wetter or drier.

They said irrigation was important in North Otago.

“It gives us the insurance to grow feed every year, which allows us to plan for the future and to create accurate budgets. For a financially stable business, this certainty is required.

“When used effectively, we believe that water is a big part of the future. With continued research and development, water use on farms will change and adapt to ensure we are making it effective and viable.”

Finding out they were finalists for the award was “really unexpected”, they said.

“We are just really stoked we made it as finalists. We see it as a recognition that we are moving in the right direction and using the process and this opportunity to take time and have discussions about how we move forward and continue to improve in the future.

“We always want to be striving for best practice environmentally, where that makes sense and is practically possible.”

The other Kiwi finalists for the award are dairy grazing and beef finishers Ben and Anna Gillespie, from Central Otago, and Mid Canterbury dairy farmer Ted Rollinson.

The Australian finalists are Victorian grain farmer Evan Ryan, Tasmanian mixed cropping and sheep farmer Stephen Eyles, Tasmanian mixed cropping and livestock farmers Rob and Eliza Tole, and Victorian cropping and sheep farmer Brendan Watson.

Head judge for the awards is Irrigation New Zealand chairwoman and Irricon Resource Solutions principal Keri Johnston.

“The finalists demonstrated a level of considered decision-making in relation to irrigation system design,” she said.

“They are all using technology to their advantage, while taking steps to maximise efficiency and minimise environmental impacts.”

Independent Australian regional judge Pat Hulme said despite the incredible diversity of the finalists’ enterprises, they had a common focus on resource management.

“We saw each of the finalists articulate, in their own way, how they see their role as stewards and caretakers of the natural resources – and they all had an eye to the long-term health of their land and water assets,” Dr Hulme said.

On-farm judging would take place this spring.

The competition is run by irrigation systems company Zimmatic with support from IrrigationNZ, Farmers Weekly, Vantage NZ, Irricon, Precision Agriculture Pty Ltd, Ag Logic Pty Ltd and the Society of Precision Agriculture Australia (SPAA).