The kurrajong tree has scars in its wrinkled trunk, the healed wounds run long and vertical under its ancient bark. Standing in front of the homestead, it nestles in a dip on high tableland from which there is a clear view across miles and miles of rolling plains to the coastal range of south-east Australia.

Charles Massy grew up here, on the sweeping Monaro plateau that runs off the eastern flank of Mount Kosciuszko, an only child enveloped by the natural world, running barefoot, accompanied by dogs and orphaned lambs. Fifth generation, he has spent his adult life farming this tough, lean, tussock country; he is of this place and it of him. But when his friend and Aboriginal Ngarigo elder Rod Mason came to visit he discovered that a lifetime of intimately knowing the birds, trees and animals of this land wasn’t significant at all.

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The tree is probably a lot older than 400 years. Rod told him that when the old women walked their favourite songline tracks they carried seeds of their favourite food and resource plants, and sowed them at spirituality significant camping places. His front garden was one such ceremony place – there would have been a grove planted, and the women had stripped the bark from the tree to make bags and material. This old tree represented a connection to country “deeper than we can imagine, and linking us indivisibly with the natural world”, he writes in his book Call of the Reed Warbler: A New Agriculture – A New Earth.

Part lyrical nature writing, part storytelling, part solid scientific evidence, part scholarly research, part memoir, the book is an elegant manifesto, an urgent call to stop trashing the Earth and start healing it. More than that, it underlines a direct link between soil health and human health, and that the chemicals used in industrial agriculture are among the causes of modern illness.

It makes a world war look like a little storm in a teacup. And we are in denial

“Most of our cereal crops, the soybeans, the corn, are all predicated now on the world’s most widely used chemical which is glyphosate [Roundup],” Massy says. “There is mounting evidence that it is one of the most destructive chemicals ever to get into the system. Its main effect is on the human gut and our entire immune system.

“When you look at the As – autism, ADHD, all the other auto-immune diseases – their take off is a 95% correlation to these chemicals being introduced. The evidence is that it affects the gut and the immune system, though it is not the sole factor, and it is a complex thing. But it is that gut that drives our whole immune system, it is our second brain.”

Facebook Twitter Pinterest ‘There is mounting evidence that it is one of the most destructive chemicals ever to get into the system,’ Charles Massy says of Roundup. Photograph: Rene van den Berg/Alamy

He says that when you spray insects with insecticides you kill off the predators so you have got to have more powerful chemicals next time because the pests come back stronger.

Massy is among scientists who believe we have entered a new geological epoch, the life-threatening Anthropocene, where human impact has permanently altered the Earth’s geology and sustaining systems, causing ecological destruction and extinction of species. “It is the greatest crisis the planet and humanity has ever faced,” he says, sitting at his kitchen table in country New South Wales. “It makes a world war look like a little storm in a teacup. And we are in denial.”

Tall, lean, fit, with white hair crowning a face that has spent a life outdoors, Massy looks more like the establishment grazier he is rather than a powerful advocate for revolutionising everything about the way we farm, eat and think about food. We are at a tipping point, he says, and if we it ignore we are “history”.

Massy spent eight years going to his office in an outbuilding behind the house in the early hours of morning to write before a day of working on the farm; the 569-page book is his life’s work; the big picture, the long view both historical and into the future that pulls together the latest international scientific research and thinking on climate change, regenerative farming, industrial agriculture and the corporations driving it.

He writes: “While consuming more resources than the Earth’s systems can replenish, we are hurtling towards multiple calamities. We are degrading the air we breathe, denaturing the food we eat and water we drink and lacing them with a witch’s brew of deadly poisons.”

We have lost touch with the land, we manipulate the Earth to our own ends, we dominate it and are ultimately destroying it. Aboriginal people, he says, saw it differently, as something to be nurtured and nourished, a living entity. He calls their custodianship “one of the greatest ever sustainable partnerships between humankind and the ecosystems they occupied”.

Facebook Twitter Pinterest The farmer, scientist and author at home on his property, Severn Park. Photograph: Mike Bowers/The Guardian

Then white Australians brought what he calls the mechanical mind and the European mind. “It is a totally different continent to anywhere else in the world. It works totally differently to that young landscape of Europe with humidity and rich soils. Until we throw off the European mechanical mind we are going to continue to stuff the joint. It is not something inanimate that you can belt. It is almost like being with a lover, you have got to nurture it and care for it.”

Now 65 and “a fossil” Massy is, by his own admission, a “biophilia”, filled with the wonder and delight of nature. “I believe one cannot gain true ecological literacy without a great empathy with, and understanding of, nature and how it functions. Thus one’s heart also needs to be involved.”

But his own journey and awakening was slow and stumbling. He was at university when, at the age of 22, his father had a heart attack and he came home to manage the merino and cattle property. Well-intentioned and diligent he read the books, he sought advice, he learned. “I thought I was running a pretty good show.” His wool was being bought for fabric by “the top guys in Italy. We were the first group to breed animal welfare-friendly sheep.” But he now realises he was “blind” and “oblivious”, he saw the landscape “as if through a glass darkly”.

He writes: “I completely overlooked the most important of all factors, the keystone of the whole operation: that our farm was a complex and dynamic series of ecological systems, and that our landscape actually functioned in specific but sensitive ways.” He made mistakes; he assiduously ploughed a paddock just before a huge storm came and washed the topsoil away, “I had cost the landscape perhaps a thousand years of topsoil.” Like many other regenerative farmers he reached the conclusion he had to make a big shift when something “cracked” his mind open.

If people ate truly nutrient-rich food out of healthy soil, you would slash the national health bill straight away

For Massy it was the years of drought, 1979 to 1983, that plunged him into depression and major debt. He finally understood that he needed a completely different mindset and management approach if he was going to come to terms with the reality of drought. “The land, soils, micro-organisms and other creatures and vegetation are adapted to this,” he writes. And so he began his journey towards enlightenment. After 35 years he went back to university and completed a PhD in human ecology, consulting everyone from scientists to Aboriginal elders.

We are driving in his ute across the plateau, cloud shadows dancing across the big-sky landscape, kangaroos and wallabies bouncing along, kelpies on the back to muster the healthy sheep. The paddocks are strewn with great monolithic rocks, 400m years old. There are birds and wildlife that have returned since he became a holistic farmer. Deep in the soil the bugs, microbes and fungi are sourcing nitrogen and nutrients. Change has to literally be grassroots, food health comes from the ground up, the health of people is entwined with the health of landscapes and soil. “The minute you fertilise and spray all that biology is gone. The vital thing about regenerative or organic farming is this healthy living dynamic soil. Landscapes with diverse arrays of plants are nutrition centres and pharmacies with vast arrays of primary and secondary compounds.”

As the dogs bound away to herd the sheep, he says, “One of the big ideas I discovered going back to uni was this concept which I came to, that our natural complex systems will self-organise themselves back to health. I think it is one of the biggest ideas. I think it is as big as evolution. It has only just emerged with physics and chemistry and computers and stuff. The Earth itself it is a self-organising regulating system.”

The human element is the problem, the learning how to live tuned to its rhythms, to get out of its way, to listen to the land. “I say confidently that not many farmers can read the landscape. For them to change they have got to admit they have been wrong for most of their lives. The thing that is challenging about it is that you have got to be totally flexible to adjustment and really get your mind into how nature works and be able to change tactics.”

He tells the story of the grasshoppers. Before he began holistic grazing the property was regularly hit by plagues of wingless grasshoppers. “They turned an OK season into instant drought. They thrive under degrading management, bare ground provides them with egg beds. But once we began our biodiverse plantings plus holistic grazing we have not had a grasshopper attack since.

Facebook Twitter Pinterest The entrance to Severn Park: ‘Now we have got 10 invaluable native grass species I never thought I would see on our property,’ Massy says. Photograph: Mike Bowers/The Guardian

“Ecological grazing yields total ground cover, higher cover, deeper roots, more moisture absorption plus more biologically alive soils; it means nematodes and other creatures eat the grasshopper eggs. You get excited when you see a new plant species suddenly emerge again. Now we have got 10 invaluable native grass species I never thought I would see on our property.”

The winter nights are cold on the plateau and, with a glass of red wine and before an open fire, Massy is unrepentant about criticising the big-end-of-town companies that promote chemicals in industrial farming, and the governments that don’t act. In the book he says unhealthy food “is not just poisoning us but is also, confoundingly, making us obese as well”. Now he says “when you are eating that McDonald’s crap even though you are bloated your body is still hungry because your organs are not getting nutrients.

“If people ate truly nutrient-rich food out of healthy soil, you would slash the national health bill straight away. The big chemical companies and big food companies know exactly what they are doing. It is now causing millions of deaths – tell me why that is not genocide?”

But just as nature find its own solutions, culling, reorganising, so too is Massy offering answers, a “toolkit” of how to change.

“This combines the best of Old Organic – namely its respect, empathy and reverence for Mother Nature – with the best of modern, ecologically simpatico science and Earth-empathic thought.” The kind of people who make the change, he found, were those with strong belief in community and healthy food that does not come from contaminated soil.

What lies beneath “is a burgeoning mass of life and activity that is 10-fold that above the ground; fungi bacteria, and other organisms have begun to create and sustain an entirely different, living absorbent soil structure; the very heart and essence of healthy farming and landscape function. The secret is to simply restore healthy landscape function and allow nature to do the rest.”

Massy agrees that he is “not naive enough to think it would be a nice seamless shift. I think we are going to see some pretty frightening stuff.”

But for him, a defining moment came when, while sitting against an old snow gum, he heard the “beautiful, piercing song of a reed warbler” returning after a long absence from this area. It was, he says, a “metaphor for us humans to once more become the enablers, the nurturers, the lovers of Earth”.

• Call of the Reed Warbler: A New Agriculture – A New Earth is published by University of Queensland Press ($39.95)