KAY Williamson stresses that they are no experts, but it’s clear she and husband Bob are well ahead of everyday gardeners when it comes to knowledge about soil, and its impact on the food grown in it.

With a long interest in gardening and nutrition, Kay says she and Bob began looking into the state of the soil on their Manawahe lifestyle block and how it affected the nutritional value of the many vegetables and fruits they were growing.

“One of our grown-up sons is a very good runner and I run too,” Kay says. “I was motivated more than ever to get the best nutrition we could from our garden.”

With that in mind, she says she and Bob attended a course run by Kay Baxter at the Koanga Institute in Hawke’s Bay. The institute is home to New Zealand’s largest heritage food plant collection and runs workshops on a range of gardening skills relating to biodiversity, organics, and producing nutritionally dense food.

Inspired, the two followed it up with an agroecology course run by a company in Huntly specialising in agriculture systems, and, she says, they studied videos posted online by American microbiologist and soil biology researcher Elaine Ingham.

“We learnt so much. I know it might sound boring but it’s actually really interesting. We get really excited about it,” she says, laughing at how the two now joke about how nerdy they have become. “We should buy a couple of white lab coats,” she says.

They then bought a refractometer, used to measure the “brix levels” of a plant, the total mass of solids such as sugars, carbohydrates and proteins (with high brix levels believed to indicate high nutritional levels), and soon after, a microscope. It was then, Kay says, that a whole new world opened up.

“It’s absolutely amazing to look at what’s in your soil. When it’s healthy and you look at it under a microscope, the soil is teeming with microbes. It’s alive with all kinds of bacteria, fungi and so on moving around, and that’s what you want to see. You want a diversity of organisms, because that’s what’s needed to grow nutritionally dense food.”

The concept of creating a naturally regenerating environment that supports healthy plants and nutrient rich food fits well with Kay’s philosophy of organics.

“I think we’ve moved so far away from nature with gardening, but actually, if you look at nature for long enough, you understand everything.”

She says soil naturally formed in environments such as the bush – where fallen leaves and debris slowly decompose to fertilising and mulching the soil below and feed the diverse range of organisms within it – is what a home gardener needs to duplicate.

While she concedes it takes time, she says by establishing a good compost regime – Kay and Bob follow the Koanga Institute guidelines – providing good mulching with fallen leaves and debris or purchased mulch, and using good natural fertilisers such as cow poo, she says a healthy and alive soil environment can be created.

“Soil with nothing moving in it is basically dead,” Kay says, and food grown in it will be nutritionally deplete. “We all, me included, seem to have a need to pick up every dropped leaf, to keep our gardens clear of anything except what we are trying to grow. We like to keep everything scraped clean, but it is that debris that helps keep soil healthy and aerated and able to store water. It needs all that fibre and mulch to generate its own nutrient-rich environment to support all the microbes and life forms in it. It’s not good for the soil or the food coming from it.”

Kay predicts that the soil quality and the increasing focus on growing nutrient-dense food is going to get a lot bigger. “It also ties with climate change because healthy soil stores carbon and poorly managed soil releases it into the atmosphere.” And aside from anything else, she says, food grown from good soil is more resistant to pests, has a longer shelf life, and definitely tastes a lot better.

Having moved to primarily using “heritage seeds”, which she says produce the most nutrient-dense fruit and vegetables, Kay is currently at the start of a new project, the development of a forest garden on their Manawahe property. This will include a combination of fruit and support trees that will grow to form six or seven canopy layers, each tree chosen to effectively feed the others, thereby creating a self-sustaining food source.

Bob is currently looking at applying the same principles to the couple’s grazing paddocks, hoping to grow grass with a higher nutrient content that is better for grazing animals, and better for the nutrient quality of the meat that comes from them.

“We are really keen to share both the good and bad ideas about what we’ve learnt with our community. Hopefully we’ll have some other soil nerds in Manawahe keen to join the discussion.”

By Lorraine Wilson