A POTENT plant fertiliser made of ground-up discarded window glass? David Archer thinks it’s a $16 billion global market, with some justification.
Mr Archer, an engineer whose Toowoomba company specialises in mineral processing, has covered a lot of ground in the years since he casually added some finely ground glass to some potted plants and watched, with surprise, as they grew "like Jack in the beanstalk".
He has since learned a lot about silicon, contracted a range of comparative studies on how glass ground down to about five micron particles - about 0.006 millimetres in diameter - interacts with plants; formed a company, and initiated patents around the world.
By the end of the year, he thinks he will have the capital in place to build a 25,000 tonne a year grinding plant in Brisbane.
With the plant built, his company Advanced Plant Nutrition will kick into high gear, turning a landfill item into a fertiliser called MaxSil that sells for about $3500 a tonne at the farm gate. Spreading rates are 50-100 kilograms per hectare.
For that hefty dent in the chequebook, growers of high-value crops like like rice, sugarcane, cotton and vegetables can expect a range of benefits, depending on the crop.
Although the mineral hasn't made agronomic headlines in Australia, its benefits have been known and expanded on since the early 1900s, when the Japanese discovered that silicon made rice more resistant to rice blast.
Since 1999 there have been five international "Silicon in Agriculture" conferences, where scientists get together to swap research notes and wonder at the fact that silicon doesn't have a larger role on farms.
Advanced Plant Nutrition has commissioned several agencies, including Landmark and SGS Agritech, to confirm the agronomic properties of its silicon product. "I don't want to be seen to be selling snake oil," Mr Archer said.
He isn't the only Queenslander excited about silicon. Another Queensland company, Agripower, is selling silicon-rich diatomaceous earth as an agricultural amendment. Like MaxSil, Agripower's product is registered with Biological Farmers of Australia as an organically-certified amendment.
But in sourcing silicon from old window glass, Mr Archer has found a unique advantage, one that has made Advanced Plant Nutrition a finalist in the 2012 Australian Clean Technologies Competition and the 2012 Banksia Awards Clean Technologies category.
Old window glass is an almost unlimited resource. Mr Archer said that China puts about 14 million tonnes into landfill each year, the United States about nine million tonnes. Australia throws away a more modest 400,000 tonnes of glass, but that still makes a lot of silicon fertiliser.
Mr Archer also claims that his product has more plant-available silicon than its rivals.
Ground glass has a long, possibly mythological association with slow murders. MaxSil is entirely safe, Mr Archer claims, and can be handled without protective equipment.
Silicon comes in two forms: crystalline, where the basic crystal forms have the jagged edges seen in beach sand; or amorphous, where the forms are rounded.
The heating process used to make glass turns crystalline silicon into the amorphous form - also the form present in diatomaceous earth. A lack of good supplies of amorphous silicon is one of the reasons the mineral has not found widespread favour as a fertiliser.
Mr Archer thinks that is about to change: in his eyes, he has stumbled on a safe, abundant recycled fertiliser product with the capacity to deliver a 200 per cent return on farmers' investment in it, and ultimately to help global agriculture produce more from less land.
Landmark apparently agrees, and has come on board as MaxSil's Australian distributor.
Mr Archer plans to develop a market for MaxSil in high-value crops first - it already has found favour with sugarcane growers around Tully - and expand into broadacre crops with a liquid version.
After Australia, the world.
The 2011 Silicon in Agriculture conference was hosted in Bejing.
"The chairman of the conference, an eminent scientist, in his opening address said that the Chinese knew that 50 per cent of their paddy is silicon deficient," Mr Archer said, "and that they would need 35 million tonnes a year to sort that out."