NZ Herald: Miah and Jenny Smith

When Miah Smith returned from hearing an Australian woman talk about supporting microbes instead of using synthetic fertiliser on his Atiamuri farm, wife Jenny thought he’d joined a cult.

A farmer down the road told Miah he built topsoil through the root system by focusing on the soil biology, and suggested he attend Dr Christine Jones’ talk.

He received – for the first time – an understanding of how soil functions.

“I went to see Christine Jones and it all clicked in my head,” says Miah. “Jenny thought I was mad.”

Says Jenny: “Seriously, I did. I thought he’d joined a cult.”

Last week, Miah and Jenny hosted 100 farmers, growers and agri-business consultants to showcase the results they’ve seen by understanding how soil functions.

“We’ve gone from $200,000 on fertiliser at that [starting] point and that’s dropped away to $60,000 to $70,000 now,” Miah told the audience in his barn.

From 2002 to 2019, farms that were dominantly dairy or grain-growing had a 100 and 187 percent increase in nitrogen applied to them respectively.

Canterbury and Waikato dairy farms had the largest amounts of nitrogen applied (53,000 tonnes each).

For Canterbury, this was 306 percent up from 13,000 tonnes in 2002. For Waikato, up 56 percent from 34,000 tonnes in 2002.

But as New Zealand farming faces two major environmental challenges of reducing greenhouse gas emissions and reducing nutrient losses to water, farmers and growers across New Zealand are already buying significantly less fertiliser according to the CEO of fertiliser co-op Ravensdown.

Ravensdown reported in 2022 that high prices and greater environmental focus have reduced nitrogen demand, cutting use over two years by 12 per cent.

CEO Garry Diack told Farmers Weekly that weather disruption and increasing fuel, interest rates and volatile fertiliser prices led to projected sales volumes for this financial year significantly down on the previous financial year, and it is unlikely that fertiliser demand will return to traditional levels in the immediate term.


The Smiths’ have reduced their nitrogen use for seven years to try and build healthy soil. Their on-farm experiment helped lead to a wider trial, established under the National Science Challenge Government programme.

Rere ki Uta, Rere ki Tai is a trial in the Bay of Plenty and Waikato, and the Smiths’ Wilith Farm is one of 10 focusing on the health – the mana and mauri – of soil, with support from scientists and others capturing the data of any changes to the land, people, and animals.

The trial is being hosted by seaweed company AgriSea. CEO Clare Bradley said in the Rere ki uta Rere ki Tai worldview, soil is valued beyond its ‘use’: “It is acknowledged for the living, interconnected entity that it is,” she says.

“Rere ki uta rere ki tai connects people and organisations who make decisions about land management with the inspiration, knowledge, and tools to transition to models which enhance the mana and mauri of soil.”

As part of the Rere ki uta rere ki tai project, AgriSea brought Dr Jones back to New Zealand to speak to farmers about how microbes in soil and plants interact, and what happens in monoculture environments like rye grass compared to paddocks with diversity. She toured Otago, Canterbury and the Waikato in April and May.

“Too often, this knowledge has been replaced by reliance on inputs such as fertilisers, fungicides, insecticides and animal health products,” Dr Jones told her audience.

“Simple changes to management practices can eliminate the need for many of these inputs and create a healthier, more profitable and environmentally-friendly outcome.”

The seminar tour culminated in the on-farm day at Wilith Farm, where Dr Jones got to see the Smiths’ farm seven years after her initial visit.



She shared how Governments elsewhere are incentivising the transition away from synthetic inputs that disrupt the microbial life in the soil.

An example was the Irish Smartsward project, with Irish farmers receiving 300 euros, the equivalent to $540 NZD, for every hectare of their land put into multi species crops that reduced the reliance on nitrogen fertilisers.

Both Jenny and Miah are now happy to host other farmers and offer advice on their experience, but believe there’s opportunity in an approach like Ireland that incentivises planting crop diversity.

“Maybe the Government could research what the Irish are doing and the positive effect and trial it, if it works carry it on and make it bigger.”

The on-farm day at the Smiths’ showcased paddocks that are far different from 2015 when Jones visited with AgriSea founder Keith Atwood to convince Jenny to trial a biological approach to farming.

At the time they were spending $200,000 on fertiliser, the soil was compacted, there was no soil life, grass grub everywhere, and no worms.

“The top soil was about 3 inches deep, we were pouring the fertiliser on and it would grow for a couple of weeks and stop again,” says Miah. “In summertime all the rye grass would peter out and die, it was challenging, tough farming.”

Adds Jenny: “There was blackberry everywhere and thistles taller than me, I remember standing on the bike trying to get rid of them.”

She describes the soil as dirt. “It had no life in it.”

“We thought artificial fertiliser would fix the soil,” says Miah, “not knowing anything about the biology and no-one had taught us from 20 years of dairy farming, we were pretty much at a loss for about three or four years.

“At the highest we were using 200 units of nitrogen and a fair bit of phosphate and potassium. You’d see grass growth for two or three weeks and then it would slow back down after that and you’d have to put it on again. There were short roots and it couldn’t handle any heat or dryness because the root system was so short.

“We had all the animal problems that a normal conventional farm had because we were using all the Nitrogen but it was really the summer that hit us hard, not having the resilience, with the hills and the rye grass.”

Recalls Jenny: “There was one year that it didn’t rain until the end of March and you would swear you were in Australia, it was so brown.”

The couple trialled seaweed products on one paddock, and later introduced diverse families of plants on the advice of Dr Jones.

After the first year there were clues that things were changing but the first two years were a struggle coming off Nitrogen. “We knew the grass was slow, obviously because we saw we’d pulled their drug away, but we saw a worm, two worms, so you knew you were doing something right,” says Miah.

By the third year the paddocks started producing a good amount of grass. “The root depth tripled, the topsoil started building and the PH came up 6 or 7 points without lime and it probably grew less coming out of winter but coming into summer it held on longer.”

Based on this they rolled it out over the rest of the farm.

Among the biggest impacts they’ve noticed is savings on animal health.

The first year that they farmed at Atiamuri there were 24 per cent empty and this has dropped to four percent last season and eight per cent this year, assisted by once-a-day milking.

“There’s no premating, no seeders and no retained membranes and only three or four with metabolic problems,” says Miah.

“You could see the results, that’s why we kept going. Financially, we’re a lot better off than what we were. We’re profitable now. And we have less sick animals, less things to deal with.”

Wilith Farm is a forestry conversion that had been farmed for three years when Miah and Jenny Smith moved in 11 seasons ago. The farm is co-owned with Jenny’s mum and dad Glenys and Alister Wilson and Aunty and Uncle Wendy and John Wilson.

*Alison Smith is following the journey of farms on the rere ki uta rere ki tai trial.

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