Beneficial fungi are disappearing from our soils at an alarming rate, but one nursery in Harcourt is hoping to reverse the trend.
Carr’s Organic Fruit Tree Nursery in Harcourt is the only Victorian supplier of certified organic fruit trees, which makes them quite a rarity. But does it really matter if fruit trees are grown organically?
To answer that, Katie Finlay from Carr’s nursery explained that we had to head into the soil.
“You’ve probably heard about the wonderful world of microbes beneath our feet. There are literally trillions of bacteria, fungi, worms, and many other organisms living in the soil,” Katie said.
“They’re collectively called the ‘soil food web’ or the ‘natural fertility system’ because it explains the way that plants naturally get their food from the soil. The system works perfectly because it has evolved with plants over the last 500 million years.”
Katie said there was a particular type of fungi that lived in very close association with most plants, including fruit trees.
“They’re called mycorrhizal fungi and they’re incredible, because they actually live inside the plants themselves,” she said.
“They burrow into the plant root and deliver moisture and nutrients in exchange for food from the plants.
“Not only do these fungi feed our fruit trees and vegies, but amazing new research is showing that they even help plants communicate between themselves, warning each other about things like aphid attack.”
Despite the fact that 90 per cent of our food plants depend on these all-important mycorrhizal fungi, they are under
attack. These fungi are fragile and are easily damaged by most modern agricultural practices like tillage, insecticides, fungicides, and weed sprays.
“It’s really alarming. Some estimates say that 90 per cent of mycorrhizal fungi have already disappeared from our soils,” Katie said.
“One of the worst culprits is artificial fertilisers. It’s like giving the plants a diet of junk food, which interferes with their relationship with the fungi.
“Over time, the fungi die out, and then the trees become dependent on fertilisers to get their food. It’s a vicious cycle.”
In an attempt to reverse this damaging trend, Carr’s Organic Fruit Tree Nursery uses a range of techniques to make sure the fruit trees are colonised with mycorrhizal fungi right from the beginning.
“We use things like green manure crops, minimum tillage, and woodchip mulch to encourage and protect the soil fungi,” Katie said.
“We aim to produce trees that are already colonised with the all-important mycorrhizal fungi when we send them to their new homes.
“It helps to recolonise the soil, and it’s the best way to make sure they’ll grow strongly right from the beginning.”
Katie said there was plenty you could do in your garden to support mycorrhizal fungi, particularly if you couldn’t get organic trees.
“Planting a green manure crop where you’ll be planting your fruit trees is a great start, but you can also make a huge difference by dipping the roots in a natural inoculant like worm wee or using a really good quality compost when you plant,” she said.
