Beneath the dung hill

Mention fossicking about in cow dung and dung beetles to those who are not familiar, and you may get a response of someone’s head slowly retracting back with full facial expressions of confusion and dismay.

Dung. Yes, that’s right. Manure. Doo-doos. POO, as otherwise known globally in many languages. The poo problem that has been concerning for decades is that huge amounts of cattle and other livestock dung had been building up to sit on the soil surface fouling up pastures; reducing good grazing pastures; ultimately, ending up in waterways contributing to nutrient loadings and posing algal risks.

One of the most annoying problems with wet dung sitting on the soil surface is that bush flies find this an open invitation to lay eggs in the dung, which, of course, cycle into the next generation of flies!

There is a solution! You may not be aware of this, but there’s a silent partner that compliments what would be a balanced relationship with dung, if left to natural devices. This humble hard-working partner is the dung beetle.

They feed partly or exclusively on faeces (dung), rolling it, and burying dung beneath the soil. A dung beetle can bury dung 250 times heavier than itself in one night. These mighty machines can outdo any farm machine when it comes to burying dung.

Photo credit: Middle - Wikipedia. Left and right - John Feehan, SoilCam.

Exotic dung beetles were introduced to Australia from 1969 to 1984 by a team of CSIRO professionals that included Mr John Feehan. When CSIRO disbanded, Mr Feehan continued his passion of getting as many dung beetles out into the Australian farming landscape, striving to reduce the loads of dung waste building up on Australian soils.

There are native Australian dung beetles, however, they cannot handle massive loads of dung from cattle and other livestock. Dung beetles that are introduced have undergone intense quarantine programs to ensure biosecurity risks are not posed.

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Dung buried by dung beetles can store carbon in three different ways (John Feehan, 2021):

• Taking organic matter underground.
• The aeration of soil resulting from the beetle tunnel system together with the buried dung produces a healthy environment for microbial activity, which in turn stores massive amounts of carbon.
• The beetles are capable of burrowing through very compacted soils. This enables grass and other plant root systems to penetrate more deeply into zones which could not otherwise be accessed. These new excavations allow grass roots to penetrate deeper into such soils thereby locking up more carbon.

Dung beetle activity in grazing paddocks and catchment areas benefits (John Feehan, 2021):

• Aerate the soil.
• Re-locates nitrogen and phosphorus in the dung to the grass root zone.
• Deepens topsoil by slowly cultivating and turning it over to a depth of 300mm, thereby producing an environment in which microbial activity thrives.
• Provides a habitat and food supply for earthworms.
• Reduces internal parasite loads in pastures through rapid burial of dung.
• Increase rain-water penetration and improves ground-water retention.
• Allows more nutrients and chemicals from herbicides and pesticides to penetrate dung beetle tunnels. This results in insecticides, wetting agents fertilizers and organic matter remaining in the paddock rather than entering waterways and dams.
• Enables the locked-up phosphate already in many Australian soils to be made available for plant utilisation via the dung beetle tunnel system.
• Reduces bush fly populations up to 99% (according to CSIRO research in Western Australia).
• Research in the USA revealed that 80% of the nitrogen in dung, when left on pastures, goes off into the atmosphere. When dung is well buried by dung beetles the loss is 20% with 80% being placed in the grass root zone.

For further details, visit: Dung Beetle Information – John Feehan.

Article acknowledgment: this article was written in technical consultation with dung beetle expert Mr John Feehan of SoilCam.