Wednesday, 13 January 2021 05:55

Scientists criticise latest 'US fad'

Written by  Nigel Malthus
NZIAHS president Jon Hickford says scientists are getting hot under the collar over the way regenerative agriculture was being uncritically embraced. NZIAHS president Jon Hickford says scientists are getting hot under the collar over the way regenerative agriculture was being uncritically embraced.

New Zealand agriculture doesn't need "the latest fad from America," according to New Zealand Institute of Agricultural and Horticultural Science (NZIAHS) president, Jon Hickford.

Hickford, a professor at Lincoln University, was commenting on the release of a special edition of the NZIAHS magazine AgScience, in which several prominent scientists pull no punches in examining the claims of regenerative agriculture.

He told Rural News scientists were getting hot under the collar over the way regenerative agriculture was being uncritically embraced.

"For some time, we have been disquieted by the ballyhoo in support of regenerative agriculture in the absence of scientific studies into the implications of applying these practices to farm practices in this country," Hickford told Rural News.

"A sound evidence base is needed to test and confirm what works in New Zealand soils, climates, and farming systems."

He says Regen Ag was becoming a political issue, with the central plank of Green Party agriculture policy for New Zealand to go entirely into regenerative agriculture. Hickford says it is also coming through in Labour Party - and thus Government - policy, with "money starting to be thrown at it".

"I'd gladly give a dollar to find out what their definition of regenerative agriculture is," he adds. "There is no definition."

Hickford says the phrase 'regenerative agriculture' sounded appealing, espectially to urban people who don't understand the complexity of farming systems.

But he claims that inherent in the term is the suggestion that our current systems must be damaged and in need of regeneration.

"Actually, what we're doing is pretty good. We could do a little bit better here, and maybe a bit more there, but the system's not broken and we don't need the latest fad from America."

Hickford says the special edition of AgScience examines regenerative agriculture in ways that were comprehensive and based on “good old-fashioned, boring science”.

“As the more outrageous claims are made by the regenerative agriculture fraternity we can say ‘well, actually the science doesn’t support that’.”

Hickford says a key argument of regenerative agriculture appeared to be a belief that we needed to get a lot more carbon into our soil.

But says it is “untrue” that most of our soils are depleted in carbon and there was “not a lot of evidence” that changing to regenerative systems would improve things.

“It (Regen Ag) seems to be promoted as a pan acea but there was no magic regenerative off-the-shelf product or process,” Hickford adds.

He says while American agriculture is having to go back to pastoralism to repair depleted soils, a lot of New Zealand farmers were already doing regenerative practices.

“We are not disturbing the soil anything like as much as in some other parts of the world.”

In his conclusion, to the AgScience publication, Hickford says there was probably a place for regenerative agriculture.

“If it is accepted as a defined system, then that system must be auditable, with clear evidence provided of benefit, be it in food quality, environmental impact or profitability,” he explains.

“Wishing your system to be better is not enough, because it must be demonstrably and reliably better.”

A number of regen ag claims questioned by experts

The publication of the AgScience special edition coincided with a MPI call for proposals for projects to investigate regenerative farming practices, to be funded through its Sustainable Food & Fibre Futures co-investment fund (SFFF), which Hickford says couldn’t come soon enough.

Among the contributors to the special edition are:

  • Dr Doug Edmeades, who addresses a regenerative agriculture theory of base-cation saturation ratio (BCSR), which is claimed to work by ensuring ‘correct’ ratios of calcium, magnesium and potassium. Edmeades says research over many years shows that ratios are unimportant so long as minimum amounts are present. Another claim promotes biologicals such as composts and seaweed extracts, but testing of biological-based liquid fertilisers found them only as good as the water they contained. “From this it appears that adopting the regenerative agriculture approach and using the BCSR concept and ‘biologicals’ would be a step back to pseudo-science.”
  • Lincoln University’s Professor Leo Condron, who disputes the worth of fertilising with coal-derived ‘humates’ – humic acids, fulvic acids and humin. Condron notes that New Zealand topsoil typically already contains about 45 tonnes/hectare of humates. “It is therefore extremely difficult to envisage that the addition of small quantities (i.e. kilograms) of humate preparation to soil in the field could make any significant difference.”
  • Lincoln’s Professor Derrick Moot and Dr Alistair Black say that grazing management is a balance between maximising pasture growth to ensure high quantities and quality of pasture, while ensuring sufficient carbon and nitrogen reserves to provide resilience to pasture plants. “The regenerative agriculture approach emphasises the latter as a way to restore degraded soils from years of continuous cropping or overgrazing in the United States and Australian farm systems. This is not applicable to the largely rotationally grazed systems in New Zealand...New Zealand grazing systems are the product of considerable and ongoing scientific enquiry underpinned by decades of research. Regenerative agriculture cannot make the same claim in any country.”
  • Massey University’s Associate Professor Kerry Harrington says regenerative agriculture seems likely to worsen weed problems, given its multi-species use recommendations and dislike of herbicides. “New Zealand agriculture is already embracing a move towards biodiversity by retiring land on steep slopes and in riparian zones, and by establishing native plants in these sensitive areas. The apparent dislike for herbicides in regenerative agriculture makes some of this replanting less likely to succeed. Some use of glyphosate in targeted areas helps get native plants successfully established.”
  • Dr Warren King, of AgResearch Ruakura, addresses regenerative agriculture’s liking for long-grass grazing systems. He found that while it might increase soil organic matter, biological activity and water retention, it will, among other things, reduce average forage quality and therefore increase greenhouse gas emissions per unit of animal production.
  • The magazine is online at

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