Glass grinder MaxSil turning waste into bottler of a fertiliser

As much as 500,000 tonnes of glass is dumped in Australian rubbish tips every year, but a young Brisbane-based silicon fertiliser business has found a way to convert that waste to a much-needed product which helps crops significantly improve their soil nutrient uptake.

Silicon also helps strengthen a plant's structure and root systems, promoting greater resilience to abiotic stresses such as dry seasons, frost and heat events, as well as improving disease and insect pest resistance.

MaxSil's new $4 million, 15,000-tonne capacity plant in Brisbane's Moreton Bay area began commercial production of its silicon fertiliser last month after pilot tests and years of crop production trials spanning cereals, sugar cane, greenhouse tomatoes, avocados, spinach, strawberries, and more.

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One particular West Australian barley trial in badly affected saline country produced the first grain crop on land which had barely grown a blade of grass in 50 years, while Queensland sugar cane returns jumped $365 a hectare.

MaxSil's glass-derived fertiliser production process is now patented in Australia, New Zealand, Europe and Brazil.

It claims to yield up to 20 times more "plant-available silicon" than comparable fertilisers which use silicate-based slag and mined diatomite to help supplement what is now recognised as widespread silicon deficiency in many agricultural soils.

Because the company's particular silicon ingredient is derived from "cooked" soda-lime silica glass, it is totally amorphous, or non-crystaline, making it easily absorbed by plants and quite different to the unhealthy silica dust produced by silica-based engineered stone.

Although waste glass recycling is widely supported by the Australian public, only a modest portion of disposed glass actually ends up being melted down and reused as new bottles and jars, largely because recycling requires different coloured glass to be clearly separated for reprocessing.

In the US about 10m tonnes of glass goes into landfill every year.

The new Brisbane fertiliser business has seized on the opportunity to make good use of the wasted resource, grinding glass, of any colour, into powder-fine particles about four microns in diameter.

It then converts those fines into fertiliser pellets to be applied with other granular fertilisers.

Alternatively, it is available as a product for foliar sprays, or slurried for furrow application, or as a seed coating.

MaxSil managing director, David Archer, began planning to get into the silicon fertiliser game a decade ago after more than 25 years in the industrial grinding business, primarily specialising in reprocessing mineral byproducts.

He had previously processed glass used as an ingredient in sprayed-on reinforced concrete in mine shafts and road tunnels, and as a sand substitute in sandblast cleaning work.

His eureka moment came at home when he applied some finely ground glass to plants and was stunned to find they grew like Jack's fairytale beanstalk.

Backed by a mix of family wealth and private investors from the mining sector, Mr Archer instigated his earliest trials in Far North Queensland sugar cane in 2014 to see the response his silicon product had helping cane plants stand more erect, improving their access to sunlight, and the crop's natural soil nutrient uptake responses.

Subsequent tests across various crops produced crop yields improvements of up to 30 per cent while also reducing the need for usual nitrogen, phosphorus and potassium fertiliser quantities and some pesticide applications.

Early agronomy trials were supported by farm services firms such as Landmark and SGS Agritech, which subsequently led to Landmark's renamed successor, Nutrien, becoming a retail distributor, along with the EE Muir network.

Mr Archer said MaxSil's extraordinarily high levels of plant-available silicon (PAS), a characteristic unique to the glass byproduct, helped plants select nutrients they needed, and sometimes avoid nutrients they didn't need.

Although MaxSil, at $2000 a tonne, was not cheap, it provided about 15 kilograms of PAS/t, which translated to $133/kg of PAS - less than a quarter the cost of competitor products.

Effective rates for broadacre cereals could be as low as 20kg/ha as a seed coating.

Mr Archer noted how global research and producer interest in silicon in agriculture had "probably increased 1000-fold in the past couple of years", although limited good supplies of amorphous silicon, and the cost of other silica products, meant the mineral had always seen restricted popularity as a fertiliser.

"We also used to assume just putting standard NPK type fertilisers onto a crop was enough," he said.

"If you had a problem, you might put lime on.

"Nowadays, the thinking needs to be much more prescriptive."

Science clearly showed silicon was an essential element for plant growth and health.

It not only boosted plant performance in mainstream conditions, it could genuinely reduce the impact of salinity, acidity and alkalinity.

"There are probably 5 billion hectares around the world affected by salt and acid or aluminium toxicity. It's a big problem," Mr Archer said.

"We've even got wheat growers in North West NSW talking to us about salinity concerns."

Saline soil agronomy trials using MaxSil were also being run by the Murray Darling Basin Authority.

Global crop input agribusinesses were showing a keen interest, too, suggesting MaxSil's market footprint may be set to grow well beyond Australia.

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