Friday, December 8, 2023

Worming their way to the top

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Slimy, slippery worms are efficiently and effectively dealing with a Northland farm’s effluent. Jenny Ling reports.
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IT’S one of the best producing dairy farms in Northland, an impressive operation that’s won the creme de la creme of New Zealand’s farming awards.

But Okaihau Pastoral is holding onto a small secret that’s proving particularly worthy in the effluent department.

Manager Joe Foster is proud of the thriving worm farm that has taken up residence in the sludge bed beside the farm’s weeping walls. 

The little critters are constantly busy, breaking down organic matter, aerating the effluent solids and transforming it into valuable fertiliser.

“The worms have set up camp in our weeping wall, which has been an added bonus,” Foster says. 

“They help compost everything down and provide a lot of nutrients too. 

“We’ve got millions of worms working for us; millions of little helpers.”

Okaihau is an equity partnership with 17 shareholders, a diverse group of people including sheep and beef farmers, accountants, beekeepers and contractors from all over the country.

Foster and his wife Jenima are shareholders and manage the Northland farm, which borders Lake Omapere in the Bay of Islands. They employ six full-time staff.

They milk 1150 Friesian and Friesian-cross cows twice daily, producing about 646,000 kilograms of milksolids a year.

The worm farm isn’t the only feature that’s helping keep the 367-hectare property, which runs on a System 5, fertile.

Since the Fosters took over its management in 2013 the farm has expanded and upgraded various areas of the effluent system, taking it from 30% to 95% of the farm.

Twin weeping walls work efficiently to filter solids and the resulting liquid is used to increase pasture production.

They recently upgraded the weeping walls from the wooden slats installed a decade ago to plastic slats that provide more consistent gaps for solids removal.

“It more accurately filters the solids out and is more efficient,” he says. 

The liquid gold sits in a huge storage pond that can hold 120 days’ effluent.

When the time is right to irrigate, when the soil is dry and conditions allow, one staff member is dedicated to the job full time to monitor and record tasks and progress.

Effluent is spread by a mono pump combined with a Cobra travelling irrigator and twin cannons.

Though the cannons have to be moved by hand the travelling irrigator can get further afield while keeping a wide berth from wetlands and waterways. The farm is replacing cannons as they wear out with low application volume travelling irrigators.

Foster credits the upgraded mono pump system for much of the system’s success. The pump miles better than the previous one driven with a tractor power take-off.

“It just spreads the nutrients out all through the farm. It’s been so beneficial,” he says.

“We’re able to get it out to all corners of the farm. We can use solids for fertilising the crops using the K2 muck-spreader that staff can take anywhere on the farm. 

“The system works perfectly. The nutrient is a valuable asset to us. We’re using what we’ve got.”

Dairy is the second largest contributor to economic activity in Northland.

Northland Regional Council says there are about 900 dairy farms with an average herd of 319 cows with average milksolids of 323kg in the 2017-18 season. That compares with Okaihau’s production of more than 560kg MS/cow.

Of those farms, 700 are consented to discharge treated wastewater to water and at least 75% of them have land application. The other 202 operate solely under permitted activity rules.

The council monitors every active dairy farm from July to November when effluent loadings are typically at their highest and with no advance notification of the inspection.

Because Northland is prone to high rainfall, with soils often saturated from May to October, the council strongly recommends enough storage be provided to hold all effluent generated.

Okaihau has its own effluent management plan, which covers staff training and operating and maintenance procedures with irrigator runs clearly marked on farm maps.

Along with the large storage pond and efficient weeping wall another management system used at Okaihau are two 600-cow, covered feed pads that let them capture effluent and recover the nutrients without rain dilution. 

After feeding the pads are washed with the recycled wastewater, which is used multiple times to limit overall water use.

The pads are also a great welfare tool, providing shelter in summer and in the wet periods of winter.

“The system works well, particularly now it’s been upgraded,” Foster says.

To keep it running smoothly and efficiently a fitness check is done at least once a year.

“We also test our own effluent every two years to keep track of all the nutrient content as well as soil testing biannually to maintain our soil health and wellbeing and fertility levels,” he says.

“We work with Ballance nutrient specialist Neil Walker and Headlands agribusiness consultant Paul Martin.” 

Martin has been the farm’s consultant since 2012. A former vet, he thrives on helping clients maximise their production and profitability while minimising their environmental footprint.

The Fosters had long been admirers of the farm they are now part of.

Joe, originally from Whangarei, and Jenima from Auckland, met in 1994 while they were working for the Conservation Department counting the kiwi and native frog populations in Northland.

Though neither is from a farming background they worked as sharemilkers on various farms in Northland from 1995 to 2003 including Dargaville, Mangonui and Houhora.

Farming has also taken them to the central North Island and Hawke’s Bay.

But it was the Okaihau farm they drove past during a holiday in the Far North that captured their attention.

So when a chance came to work on the farm they jumped at it.

When they took over in 2013 the farm had produced 347,000kg MS for the season. It increased to 449,000kg in their first season and rose again to 580,000kg in 2016-17. 

The couple became shareholders in 2016 and a year later Okaihau was named Dairy Business of the Year runner-up.

In July the business scooped the top award and was Best Northland Farm Performance for the third time as well as the High Input Farm with Best Financial Performance.

Judges noted Okaihau’s strong metrics that included the highest per-cow production, 538kg MS, and a cost of production of $4.01/kg MS. 

The farm is governed by a board that includes four shareholders and Martin as an independent director. The judges commended the strong governance and how well management works with the board to achieve results.

Foster sees the competition as a win for the whole of Northland along with the shareholders, who visit the farm annually.

The environmentally focused farm is actively pursuing a philosophy of leaving the land in a better state for the next generation. 

Extensive planting has been done on riparian land including a 30ha buffer zone around Lake Omapere using a mix of natives and poplars.

They are constantly adding to the farm’s wealth of trees and last year planted another 5000.

They also have dozens more seedlings waiting to be planted.

“It’s quite an investment,” Foster says. 

“We’ve spent a lot of money on trees over the years.”

Because of the area’s high rainfall and the size of the farm they have really tried to narrow down the things required in the future they can work toward, Martin says.

“Hence why we have the ability to have three irrigators working simultaneously, irrigate large areas of the farm and stay ahead of regulation. 

“Because of our soil type and rainfall we need to be able to spread effluent at a low rate over a large area. We’re trying to stay ahead of the game.”

Martin, who lives on a family farm at Whangarei running drystock and growing avocados, says farm profitability is key.

“It’s hard to be green if your business is in the red so farm profitability is key to allowing sufficient investment in modern effluent management strategies and environmental improvement. Okaihau aims to set the bar high in this regard.” 


A field day will be held at Okaihau on November 19

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