CHEF Matt Wilkinson holds a moist, chocolate-brown mound in the palm of his hand. ''Smell it,'' he says, in his blunt Yorkshire accent. ''Good enough to eat.'' At that moment a small worm emerges from the pile and arcs its little body around in the air. Wilkinson smiles. ''Signs of life means healthy soil,'' he says.
He returns the clump of earth to the vegetable patch behind his East Brunswick cafe, Pope Joan, and carefully covers it with mulch. ''Food grown by the farmers who care for their soil not only tastes better but lasts longer,'' he says.
Wilkinson came to rethink the produce he used in his own kitchens when he performed taste tests on vegetables sourced from farms practising different techniques. ''Out of broad-scale vegetable production, large-scale organic production and small-scale organic farms, it was always the smaller farmers, who concentrated on creating good soil that was brimming with life, who grew the best food,'' he says. ''But it's the bugs and microbes you cannot see that make healthy soil.''
Wilkinson is part of a global wave of chefs, farmers and activists encouraging us to change the way we think about the earth beneath our feet. Soil health and human health are intertwined and there is a microscopic underground army that, if recruited, could do away with chemical fertilisers, pesticides and even, perhaps, tractors and ploughs.
Half a world away, Swedish chef Magnus Nilsson uses his intimate understanding of soil to influence the flavours he delivers to the table at Faviken, his 12-seat restaurant on a remote 10,000-hectare hunting estate in Jamtland, 600 kilometres north of Stockholm.
''If you grow vegetables, it is essential to have living soil,'' says the man more associated with Viking bloodlust and dispatching and butchering the animals he serves. Nilsson, a guest of next month's Melbourne Food and Wine Festival, has two gardeners and grows three tonnes of vegetables in soils he and the gardeners have built up using a non-dogmatic application of organic and biodynamic methods, rotating crops and digging in green ''manure'' crops to feed the bugs that create nutrients for more plants. ''You know you have living soil when you dig through it,'' he says. ''All the worms and bugs. You can feel it is alive.''
The chef celebrated the processes of growth and decay in his famous dish ''Vegetables Cooked with Autumn Leaves''.
''We cook the potatoes with plenty of autumn leaves that have been lying outside for almost a year since last autumn and are already starting to decompose into humus-rich soil,'' he says. ''The only difference between a fallen leaf and soil is the time it takes to decay.''
Out in the Grampians, chef Dan Hunter of Dunkeld's Royal Mail Hotel has recruited his army to turn tonnes of plant material and animal manure into rich compost that, in turn, enriches the soil in which he grows most of his vegetables for his The Age Good Food Guide three-hat restaurant.
''In the past 18 months we have had a massive change in the way we approach gardening,'' he says. ''Here we don't grow vegetables, we grow soil,'' he says, referring to the three 15-metre-long composting bays. ''Since we have focused on getting the soil perfect, we have seen a massive increase in the quality of our vegetables. Our purple sprouting broccoli has a depth of flavour that wasn't there before. Our beetroot have aromas of red berries, sweet soil and,'' he says with a little pause, ''chocolate.''
Out in the heart of the old Koo Wee Rup swamp is a scientist as passionate about soil as Hunter is about his vegetables. ''Don't call it dirt,'' Dr Mary Cole says. ''It's soil. And soil is a living thing.'' Outside her high-tech, airtight laboratory on a secluded farm to the south-east of Melbourne, she invites me to take a handful of the earth in which her tomatoes are growing. It has an inviting, sweet aroma. Under a high-powered microscope, the soil is a lively game park with hundreds of bacteria and hair-like filaments of fungi. Cole explains that bacteria help form soil from rock by breaking it down. They excrete a glue-like substance that binds the particles of sand, silt and clay. Some fungi (mychorrhizae) have a symbiotic relationship with plants. Filaments of fungi link up with the roots of plants and the fungi exchanges nutrients for energy in the form of starch and sugars the plants have created through photosynthesis.
''If farmers work with these microbes,'' Cole says, ''they will work for the farmer, silently, night and day, creating more soil, for free, for the rest of the farmer's life and well after he's dead and gone.'' Soil farmed using these methods, which include biodynamic and organic farming, produces healthier food, she says.
''There are peer-reviewed studies that show that there is a measurable difference in things such as Vitamin C, phenolics and anthocyanins [antioxidants].''
She pauses, adopting a more sombre tone. ''Unfortunately, a lot of these beneficial fungi and bacteria are either destroyed or hampered by the application of chemical fertilisers.'' Once naturally occurring soil fertility is lost, plants then rely on artificial fertilisers to grow.
Horticulturalist Annie Raiser-Rowland knows the power of working with nature. Her workshops teach city gardeners how to make healthy soil.
''Most people don't look at soil as a living thing,'' she says. ''I describe the surface of the soil as a delicate newborn that needs covering, as in mulch. Soil life is what feeds plants. It is not inert.''
Using microbe-filled compost, Raiser-Rowland transformed her own garden from rock-hard clay covered in car engine oil and concrete into an urban oasis with 20 centimetres of rich topsoil. ''There has been a massive shift in the way people are thinking about soil in just the past few years,'' she says. ''Three years ago the workshops were a hard sell but, with the rise of the inner-city vegetable gardener, people are finding that they have issues … Foodie gardeners know a lot about soil and are keen to learn more.''
She says people don't mulch enough, they don't think enough about drainage and they don't understand the need to balance carbon and nitrogen or plant matter and animal manure.
Not far from Mount Baw Baw and beside the LaTrobe River, farmer Liz Clay grows some of the best vegetables in the state. Her family were market gardeners in Keysborough and later Barham on the Murray. She settled on this old dairy farm surrounded by towering mountain ash 30 years ago while still working as a teacher. Eight years later, the call of the land became overwhelming and she returned to growing vegetables. She offers a bean from her patch growing next to regenerated bushland. It is truly delicious. ''I don't describe what I do now as market gardening but garden farming,'' she says.
On one hill pumpkins grow, tendrils embedded in the red earth. There are potatoes, strawberries and corn. She half jokes that she employs a workforce of millions. The farm's compost is a blend of chopped plant material and animal manure teeming with life and interlaced with the tiny white fibres of fungi. ''By learning how to work with microbes, they do our fertilising, our pest control, they look after soil fertility, nutrients, moisture retention, sequester carbon and protect waterways,'' Clay says.
''Over the past decade, there has been a huge change in Gippsland with farmers leading the way and taking up the challenge to move to cultivate the soil. The conversation has started and it's getting louder.''
Back in town, Wilkinson pushes his fingers into some heavy earth growing some rather small eggplants.
''We had a real problem with drainage and soil structure here, so we grew a crop of potatoes and they literally pushed the soil apart.'' Wilkinson has teamed up with a grower in Glenlyon on the slopes of an extinct volcano with rich, red soil supplemented with compost. Select seeds of carrots and exotic vegetables will be planted.
''Customers have put their trust in me that I am using really good produce,'' Wilkinson says. ''So I found a farmer whose objective is to look after the soil to make better-tasting, healthier food. I think everyone wins.''
Where to learn more
■ TURNING ''dead dirt'' into healthy soil, sustainable living educator John Purtill runs soil health and composting workshops at his two-hectare intensive sustainable garden called The Garden of Eaten, Lara. Phone 0418 354 500.
■ MARY Cole runs regular soil and compost workshops at her farm and locations around the nation. agpath.com.au
■ THE Understanding Soils Workshop is a day-long workshop with horticulturalist Annie Raiser-Rowland. Learn how to identify problems with soil and how to correct them using organic techniques. May 12, 10am-4pm, CERES, East Brunswick, $95, 9389 0100, ceres.org.au
■ GROWING food is a life skill, just like cooking, says Josie Charles from the Stephanie Alexander Kitchen Foundation. The foundation holds regular workshops that cover soil health. The next is Principals of Organic Gardening, May 16, 10am-noon, Collingwood College, $65, register at kitchengardenfoundation.org.au
■ THE Diggers Club holds gardening workshops every second weekend at Heronswood in Dromana and every month at St Erth, Blackwood. Compost, Soil and Worms is a workshop explaining how to turn kitchen and garden waste into compost using different techniques. June 2, 10am-11.30am, Heronswood, Dromana, $35, 5984 7321.
■ MORE than 25 years ago, Marg and Jason Alexandra planted their Hazeldean Forest Farm in Ellinbank, south of Warragul, with thousands of trees. This half-day family discussion and farm tour explores the trials and tribulations of farming and caring for the earth. Growing Farmers, February 24, 10.30am-2.30pm, Hazeldean Forest Farm, Hazeldean Road, Ellinbank, 0438 943 196, $50, light lunch provided.
■ THE City of Kingston runs regular composting workshops for residents. firstname.lastname@example.org
■ INTERNATIONAL Composting Awareness Week is May 6-11. compostweek.com.au
■ Magnus Nilsson takes part in Theatre of Ideas at Hamer Hall on March 10. melbournefoodandwine.com.au
Matt Wilkinson writes a monthly blog for goodfood.com.au, Mr Wilkinson's Fresh Talk.