Prominent New Zealand agricultural scientists are worried the hype surrounding regenerative agriculture is allowing unproven theories and practices to take hold without sound scientific backup.
“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,” says Lincoln University professor Jon Hickford, who is president of the NZ Institute of Agricultural and Horticultural Science (NZIAHS).
Hickford and other scientists have written a series of articles in the institute’s online AgScience magazine, published at the end of last year, which raise critical questions about the benefits of regenerative agriculture.
“Before we choose to become too enamoured with regenerative agriculture, it needs to be subjected to rigorous scientific scrutiny,” Hickford argues.
“These articles lay the foundation for how we should start the process of thinking.”
Retired scientists Warwick Scott and Derek Wilson write that regenerative agriculture originated in the US in response to soils there becoming damaged by inappropriate land-uses, notably exhaustive cropping in unsuitable situations, and then spread to Australia where poor soils with low fertility were also cropped exhaustively. But they say soils in NZ are different.
“Recent advocacy of regenerative agriculture in this country is based on the presumption that our agricultural systems are degenerated. They are not and the current claims that regenerative agriculture is needed to rescue them are misplaced. It has little relevance,” the two scientists say.
Lincoln University professor Leo Condon adds that some of the practices promoted by regenerative enthusiasts, including the use of bio-stimulants such as plant growth promoting microbes, effective microorganisms, phosphate solubilising microorganisms, compost teas and humates have been subject to extensive investigation around the world and, for the most part, have been shown to have no significant impact on plant growth and soil biology under field conditions.
Massey University associate professor Kerry Harrington is concerned regenerative practices could see an increase in difficult-to-control weeds.
“Some regenerative agriculture proponents advocate highly complex pasture mixtures and grazing them less tightly than in conventional agriculture,” Harrington writes.
“But unless sowing rates are kept low, only the most aggressive species survive. If sowing rates are kept low enough to allow some of the more useful species to establish, weeds will also establish.
“Research funding is better directed toward improving the effectiveness of current weed control efforts than thinking that eliminating herbicides and moving to complex pasture mixtures will solve problems for farming and the environment.”
Article by article, the writers present scientific facts about NZ agriculture that they say are being ignored by many in the regenerative movement.
“These scientists have been studying various aspects of the New Zealand managed ecosystems for decades, specialising in soils, plants and animals, as well as the environment,” Hickford says.
“They are concerned that people from overseas advocating a change cannot appreciate the unintended consequences.”
Hickford says current NZ agricultural and horticultural systems are far from perfect and work must continue to make them environmentally sustainable.
“We have wrought considerable damage to the environment in our short occupation of this land, and issues such as water quality, greenhouse gas emissions and biodiversity are important to all New Zealanders,” he says.
But he argues changes to existing systems must be backed by facts not romantic notions, citing one “appealing statement” as an example: “The cycle of life creates its own fertiliser”, but dismisses it as biological, chemical and physical nonsense.
“It is easy to state you have undertaken decades of scientific and applied research, but where is that research published, how accessible is it to the public (scientifically literate or not) and has it been peer reviewed?” he asks.
“The world is awash with attractive ideas but we need to see the hard evidence that regenerative agriculture will capture carbon in soil, reverse the atmospheric accumulation of CO2, increase yields and provide resilience to climate instability (just some of the many positive attributes claimed).
“And even if it does demonstrably do these things in overseas countries, will it do the same in New Zealand? Our production systems and climate are different in many critical respects.”
NZIAHS has welcomed a call by MPI for proposals that will investigate regenerative farming practices, with funding for successful proposals to be made available through the Ministry’s co-investment fund.
“It can’t happen soon enough,” he says.
