Soil Carbon: How Silicon Fertiliser Is Linked to Higher Soil Organic Carbon

The University of Melbourne findings

University of Melbourne field trials in Victoria in 2022 and 2023, using Scepter wheat, produced a result that got people's attention. At the Birchip site, foliar silicon plots had a significant 13.19% increase in soil organic carbon, and soil applied silicon plots had a significant 11.28% increase.

Now the honest part, because this matters: the researchers themselves said more work is needed to confirm whether this is a one off or an ongoing trend. Two seasons at one site is promising, not proven. We repeat that caution because if you are making decisions about carbon, you deserve the straight version.

With that said, the result fits a plausible mechanism, and the mechanism is worth understanding.

Phytoliths: how silicon can protect carbon in soil

Plants that take up silicon deposit some of it as phytoliths: microscopic silica bodies that form inside and between plant cells. When the plant dies and returns to the soil, the phytoliths remain, and carbon trapped inside them is physically protected from decomposition.

This is one of the ways silicon is linked to longer lasting soil carbon. The silicon itself is not carbon, but it can act like a tiny glass case around carbon, slowing its return to the atmosphere.

It is an active area of research, not a settled accounting method. But it is a real, published mechanism, and it is why silicon keeps coming up in carbon farming conversations.

The recycled glass angle

There is a second, more direct carbon story with MaxSil. It is made from 100% recycled Australian glass under an EPA end of waste code. Every tonne of MaxSil is glass that did not go to landfill, and using recycled glass cuts the embodied carbon compared with virgin mined inputs.

For growers, that is a nice story. For the companies buying your grain, livestock or produce, it is becoming a procurement question.

Soil carbon and Scope 3: a note for processors and lenders

If you are a food processor, retailer or lender, you already know Scope 3: the emissions embedded in your supply chain, most of which sit on farms. FLAG (forest, land and agriculture) reporting is pushing those numbers into annual reports.

A farm input made from recycled glass, linked in field trials to higher soil organic carbon, is the kind of lever supply chain programs look for. If you are building a Scope 3 or FLAG program and want to talk about supply chain trials with MaxSil, get in touch.

One thing we will not do is promise carbon credits. Read the FAQ below for why.

How to increase soil carbon, the practical version

The fundamentals have not changed: keep ground cover, retain stubble, grow roots for as much of the year as possible, add organic matter where it pays, and do not cultivate more than you have to. Silicon is an addition to that list with early trial support, not a replacement for any of it.

If you want to test silicon on your own place, the approach is the same as any other input: a strip trial, measured properly. MaxSil offers a free soil test analysis to establish your baseline, and recommends a tissue test about 2 weeks before harvest to measure the plant response.