28/10/2026
Biologicals: What Does an Agronomist Actually Need to See?
There is plenty of discussion at the moment about why agronomists and growers may be slow to adopt biologicals and biostimulants.
From my perspective, we need to be careful not to confuse healthy professional scepticism with resistance to change.
I’m not anti-biological and I’m certainly not wedded to conventional chemistry. I’m pro-results.
I advise across conventional agriculture, including synthetic fertilisers and pesticides, biologicals, biostimulants and recycled organic inputs such as poultry litter, manure and compost. I’m not particularly interested in being tribal about any one production system. They are all tools in the toolbox.
I have plenty of clients who follow my recommendations on products and approaches from Metagen, Bayer’s Prime Extra, Biocoat VAM and Azospirillum products, natural zeolite, manures, poultry litter and composts. When I know I can get a better result for a client from one of these approaches, I push it. When I can’t demonstrate that advantage, I’m quite comfortable staying with proven, cost-effective conventional inputs.
The question I keep coming back to is simple:
What is limiting this crop, and what is the best tool or combination of tools to improve the outcome?
When I tell a supplier,“I need more data,” I actually mean it.
What does the product do? Why should it work? Under what conditions does it work? Where might it not work? How consistent is the response? And, importantly, is the improvement sufficient to justify the grower’s investment and change from what they are already getting good results from?
For me, the standard should be the same whether we are talking about a pesticide, fertiliser, seed, animal health product, biological, biostimulant or recycled organic input:
Where is the evidence? Is the response repeatable? And does it produce a predictable improvement in profitability, productivity, crop health, soil health, animal health or resilience?
Ideally, we want several of those outcomes together.
Agronomists also carry some of the risk. It isn’t our paddock or crop, but we have put our professional judgement and reputation behind the recommendation. We aren’t treating a plant in isolation. We’re advising the person whose livelihood depends on that crop. If we get the judgement wrong, it can cost our client real money.
And farming margins can be much tighter than many people outside agriculture appreciate. Saving $50,000 by removing a proven input isn't an achievement if the result is $100,000 less margin because harvestable or packable yield has fallen. Equally, if a biological costs money but reliably produces an improvement worth substantially more than its cost, it deserves serious consideration.
That is why I am not prepared to risk the financial wellbeing of my clients, and ultimately my own, without multiple datasets showing that something works under Australian conditions. I also want some of that evidence to be as local and relevant to the farming system as reasonably possible.
We expect evidence, consistency and accountability from seed, fertiliser, animal health and pesticide companies.
Why should we lower the bar for biologicals and biostimulants?
I also don't subscribe to the idea that farmers and agronomists have suddenly discovered soil health, or that conventional agriculture has somehow ignored it. Farmers and advisers have been questioning, adapting and looking after their land for generations. Being sceptical of a conventional input is part of good agronomy. So is being sceptical of a biological one.
As the pig farmer next door to my parents’ farm used to say:
“You can’t smell the pig on the cheque!”
A fairly blunt bit of old-fashioned farming wisdom, but there is an important point behind it. We all need a sustainable income first. (Pigs, by the way, can be a bit too smelly for the average person, farmer or not)
Profitability and sustainability shouldn't be treated as opposing objectives. A farming business needs to remain financially viable if it is going to keep investing in its crops, livestock, soils, people and future.