Snouts unearth soil secrets

In Tasmania the seasons are distinct. Spring is unpredictable: windy and wet days interspersed with sunshine. In summer the days are long and it’s usually warm and dry. Autumn - which is our favourite time of year - is calm, mild and pleasant, but winter is the most challenging: cold temperatures, short days, and high rainfall.

It’s the time of the year when being a free range pig farmer can be difficult. Mount Gnomon Farm is up against the west side of the Dial Range, just south of Penguin. It’s already a high rainfall part of Tasmania, and being directly under Mount Gnomon we seem to get extra - even compared to our neighbours just a kilometre down the road. On average we receive over 1000mm of rain a year.

Fortunately, we have the north-west’s famous chocolate soil which has a reputation for being among the finest for agriculture in the world. It’s deep, well-structured, and free draining, and it’s one of the main reasons why this region produces some of the world’s finest food.

Not everybody gets excited about dirt, but the type of soil you have is extremely important if you want to farm free range pigs without ruining your farm. Keeping pigs on the wrong soil would mean a lot of mud and soil destruction. Some consultants say you shouldn’t keep pigs outside if you get more than 800mm a year. But because we’ve got this good soil, and we’re on the crest of a hill, we can farm our pigs sustainably.

The extra rainfall is actually good - if you can put up with wearing wet weather gear six months of the year - because it helps us grow more grass and forage crops for the pigs, which of course adds to their flavour.

The pigs are amazing ploughs. We don’t put rings in their noses to stop them rooting the ground, because it’s such a natural instinct for them to turn it over with their rubbery snouts. We recently moved some of our growers close to the house so they could dig up our future berry patch and clear up the twitch and other weeds. That’s better than having to get out there with a fork.

The reason pigs like to dig is related to their taste buds - they like variety in their diet. In Europe traditionally they would turn the soil looking for nuts, worms, roots, and of course truffles, which supposedly release similar pheromones to that of a boar.

When one of the big pig breeders from the mainland visited our farm she was amazed at just how much our pigs root. They don’t do that at her place, she said. But we’ve not seen a free range pig in Tasmania do otherwise, except when it’s bone dry in summer.

We think it’s perhaps the extra moisture and the fungi in the soil that encourages the excessive digging. Tasmania’s soils have extremely high and diverse fungi populations. It’s partly because we have limited numbers of termites, so fungi play a vital role in breaking down plant material and making nutrients available to plants. If you looked in our bush or explored the local Tarkine rainforest you’d find a huge variety of fungi. But whether it’s the lure of a truffle or a wriggling worm, pigs certainly get a lot of pleasure from using their powerful snouts.

The other good thing about the soil and its related biodiversity is that it helps our pigs build up their immune systems. It also gives them essential iron. In commercial piggeries farmers actually have to give iron shots to their piglets to prevent them becoming anaemic.

Our red soil has lots of iron in it, and the piglets start nibbling away at it when they’re only a few days old. We wonder just how much soil a pig actually eats in its lifetime, and we’d like to know more about how the soil contributes to the flavour of the meat.