On tiny wings, angels of Earth replenish the soil and multiply

The cows at ‘Leeston’, north of Goulburn, are more approachable these days.

“They no longer see us as an enemy; they’re seeing us as a friend,” Wayne Rabjohns says.

Over the past five years, the 300-hectare property at Woodhouselee has been divided into long lanes, smaller paddocks and has doubled its carrying capacity. Wayne and his son Adam expect this will soon triple.

Critical in this turnaround are dung beetles, each no bigger than a little finger’s thumbnail. They’re multiplying rapidly and burying truckloads of dung into the soil.

That’s essential to enable ultra-high-density grazing, where 400 cows on a one-hectare paddock eat the grass and weeds down by 90 per cent. They’re moved three times daily to keep fresh pasture up to them.

“Now we see them every day,” Adam said. “I quite often walk the fence line out, putting in my temporary posts, checking the soil, checking the dung. The cows come to us; they know their next feed is coming very soon; they come up and want to sniff your hand.”

This is a different scenario to the previous one in which Adam checked cows weekly on a motorbike and was disconnected from them. They would see the bike and run.

Dung beetles arrived at Leeston in the 1970s when Joyce Rabjohns took up an entomologist’s offer on ABC radio of experimental species offered by the CSIRO.

Although the beetles established themselves, little else changed on Leeston.

The dramatic change followed Joyce’s son Wayne and grandson Adam’s decision in 2020 to begin regenerative farming, a more sustainable model requiring research and rotating smaller paddocks for ultra-high-intensity grazing.

For that level of intensity, improvement in pastures and managing the heaps of dung left in the wake of cattle are essential.

A cross between Mashona, a breed which originated from the Shona people of eastern Zimbabwe and Angus, the cattle dump 16 tonnes of dung and urine – enough to fill one semi-trailer load – in the paddock every day.

That’s when these champion little beetles do their best work, rolling pieces of fresh cow pat into tiny balls, tunnelling into the soil with them and leaving each ball behind to feed on their larvae.

“So that hectare that is being grazed has a huge amount of biologically active nutrients being put back onto it straight away, so that increases the growth significantly too,” says Adam.

“If you were trying to pay for that (amount of nutrients), bring that in and spread it about, it would send you broke,” he said. “So by doing this you are having a massive impact.”

For more than 50 years Canberra entomologist John Feehan has championed the dung beetles and credits them with reducing numbers of bush flies. Populations of these flies had exploded as higher numbers of cattle overwhelmed dung beetles, until Feehan’s reinforcements arrived.

In 2022 the Rabjohns introduced three warm season dung beetle species, Onthophagus vacca, Bubas babalus, Geotrupes spiniger and a winter active species, Bubas bison to Leeston.

“There are probably three or four existing species between the native and introduced species already,” Adam said. “Our long-term goal is to have every available dung beetle that will survive in our climate hosted on our property.

“Each year dung beetle activity increases to where we are now seeing large amounts of activity in every dung pat within 24 hours.”

Digging under a dried crust of cow pat today reveals a fine mound of compost and the patch peppered in holes left by the tunnelling beetles. This means far greater water penetration into the earth.

Adam said because the cows were grazing together the beetles didn’t have to travel as far. “They are right there with the cows every day instead of being spread out trying to find dung,” he said.

Flocks of starlings are joining in the action says Wayne. “This is very African-like. You’ll see the starlings sitting on the cows’ back and next thing you’ll see the starling down right beside the cow walking between its mouth and feet,” he said. The birds are dining on bugs and spiders in the lush pasture.

The Rabjohns have been reducing anti-parasitic chemicals on the cattle because they pass through the animal and kill dung beetles. The aim is to protect the dung beetle, the soil’s natural best friend.