A very simple high school experiment with soil can tell us all about it.
The University of Tasmania’s Dr Richard Doyle hosted a dozen science teachers and scientists to sit down with a dissecting microscope and two small plastic containers of soil.
It was simple: one sample of soil came from a dry cropping paddock which had not been ploughed for more than a decade; the other from a frequently tilled one.
‘Soil Doyle’ (to his students) asked us to count how many animals we saw and, without a worm in sight, interest waned.
“Look closer,” we were instructed, so we zoomed in.
A myriad of small invertebrates raced among the large clots in all sorts of sizes and shapes, and we counted hundreds between us.
We then inspected the sample of frequently ploughed soil and there was not a critter to be seen.
Tillage has undergone extensive research in Australia from the mid-1960s when it became apparent soil erosion and water retention were challenges for Australian dry crop farmers.
Results vary depending on circumstances, crop choice and location such that it’s no moot point: farmers adapt as they see fit.
What we had disturbed in our little experiment was a soil ecosystem about which scientists know relatively little, and yet our observations didn’t consider the fungi and bacteria that we could not see.
The often-touted belief that there are more microbes in one teaspoon of soil than there are humans on the earth needs scrutinising, but not for long.
It’s almost true, in fact there’s possibly more.
Ohio State University scientists reported that up to one billion bacteria can inhabit that teaspoon of dirt, and bacteria are just one group of microbes.
More important, I think, is Swiss ecologist Mark Anthony’s 2023 study that went further and found that more than 50 per cent of the planet's species live underground.
The count of different species is equally as important as the sheer numbers.
Imagine the myriad of complicated food webs and ecosystems trying to stay in careful balance above the ground while us humans blunder about burning, harvesting and poisoning as we grow food.
If that same amount of completely different species exists underneath our feet, we need to look closer.
Callum Lawson will next month sow near Avenel another 200 hectares of an expanding trial plot of a diverse range of plants along with organic additives, organisms and even complex sugars, to nurture the microbes and invertebrates that flourish in the soil and so allow his unique pasture to flourish.
He doesn’t till.
His alternative pasture produces much more productive cattle and I for one have never seen shinier coats.
At next month’s Seymour Alternative Farming Expo, at least two companies will showcase biological additives for the farm and garden, one of which works in conjunction with spraying herbicides.
Mark Gabsch from Bactivate is even offering soil tests for any samples brought to his stall to measure the ratio of bacteria and fungi to determine the best additive for any visitor’s home or farm situation.
I’ll be in the queue with a handful of dirt from my modest no-dig vegetable patch.
We can never expect to have a comprehensive picture of the specifics of underground ecosystems but the case for non-tilling is very good with numerous reports measuring stronger and, in some situations, more yielding crops when those underground critters and microbes are well-fed and not disturbed.
And although a finely ground tilth might seem easier on the roots, I asked Dr Doyle if I was overdoing it in my garden with the 10 goings-over with a rotary hoe.
He mimed with his hands one simple gesture of using a plough board to turn a large sod over twice.
“Don’t worry about hard soil,” he said.
“Roots are designed to crack through almost anything."
Andy Wilson writes for Country News. He is a pre-peer review science editor in a range of fields and has a PhD in ecology from the University of Queensland.
10°C