Insect larvae are being recruited by the millions to turn dirty and smelly waste from livestock industries, including pork and poultry, into stable and effective agricultural fertiliser.
- Researchers are feeding commercial livestock manure to insect larvae
- They say soldier fly larvae will eat anything from kitchen scraps to manure
- Trial plants grown with fly fertiliser are thriving
A trial to feed manure from piggeries, chicken and other livestock farms to the larvae of black soldier flies is showing promising results.
Untreated manure produced by the 500,000 pigs grown in Australia each year is rich in nutrients, but it’s not safe to use on all food crops.
West Australian environmental company Future Green Solutions is working with a group of producers including Australian Pork Limited as well as the University of Western Australia on a $2.5 million project to test the insects’ ability to eat large quantities of animal manure.
Future Green Solutions managing director Luke Wheat says the lifecycle of the flies, that are endemic to Australia, makes them useful for processing all types of waste.
“The soldier fly larvae are a fairly non-select feeder so they’ll eat anything from kitchen scraps, fruit and vegetable waste, meat waste and even some more problematic waste streams like manures,” he said.
When black soldier fly larvae hatch from tiny eggs they eat as much as possible, as quickly as possible.
“The adult part of the fly doesn’t have a requirement to feed, essentially what that means is the larval phase needs to gain as much energy and nutrition as it can to survive through pupation and breeding.
The fertiliser product is the larvae’s own manure: a dry, stable, surprisingly earthy-smelling organic material called frass.
Senior research officer at the University of Western Australia, Daniel Kidd has found using various rates of frass as a soil improver beneficial in wheat, canola, ryegrass and clover trials this year.
“Certainly as an organic fertiliser, I think it has great promise,” he said.
Currently 60 per cent of the pork industry is powered by energy produced with methane gas collected from effluent ponds.
Australian Pork Limited chief executive Margo Andrae said the rest of the manure was left in the ponds until it dried out and had limited uses.
“You can use it for your landscaping, you can use for regeneration, but what the black soldier fly does is gives us a lot more opportunities for where we can use that because it’s been processed,” she said.
The project will now consider yield, grain quality impacts as well as methods to efficiently transport black soldier fly products.