What Is a Biostimulant — and How Is It Different From Fertiliser?

If you've spent any time looking at soil health, biological farming or newer agricultural inputs, you've probably come across the word biostimulant.

It's also one of those words that can mean very little if nobody actually explains it.

So what is a biostimulant?

Is it fertiliser?

Is it biology?

Is it something you use instead of N, P, K and S?

And what exactly is it supposed to do?

At Bio Charge, we think the simplest place to start is this:

Fertiliser primarily supplies nutrients. A biostimulant is primarily about supporting the processes that help plants and soils access, cycle and use nutrients and respond to their growing environment.

And importantly, the two don't have to compete with each other.

In fact, we think asking whether you should use fertiliser or biology is probably the wrong question altogether.

What happens below ground has a huge influence on what happens above it.

There are different definitions used around the world, but at its simplest, a plant biostimulant is a product designed to stimulate plant nutrition or plant processes independently of simply supplying large quantities of nutrients.

The areas commonly associated with biostimulants include:

• improving nutrient-use efficiency;
• improving the availability of nutrients around the root zone;
• supporting plants through environmental stresses;
• supporting root-zone processes; and
• influencing plant quality or performance.

That's an important distinction.

A biostimulant doesn't necessarily need to contain large amounts of N, P, K or S to have a role within a farming system.

Its purpose can be to influence how the system functions rather than simply adding more nutrient.

Traditional fertilisers are generally fairly straightforward.

If your crop or pasture needs nitrogen, you apply a nitrogen source.

If soil testing identifies a phosphorus requirement, you may apply phosphate.

The fertiliser's primary job is to supply a nutrient.

A biostimulant approaches the system from another direction.

Rather than asking only:

“How much nutrient can we add?”

We're also interested in:

“How well is the soil and plant system using what is already there?”

That's where things such as roots, microorganisms, carbon, organic matter, moisture, soil chemistry and nutrient cycling start becoming important.

Fertiliser and biostimulants do different jobs. We don't think farmers should have to choose one camp or the other.

But there's an important catch.

A product can contain both.

And that's where the line becomes much more interesting.

Agriculture has a habit of turning things into opposing camps.

Conventional versus biological.

Synthetic versus natural.

Fertiliser versus microbes.

We don't think soil works like that.

A plant still requires nutrients.

Nitrogen doesn't suddenly become irrelevant because you're interested in soil biology.

Phosphorus is still phosphorus.

Potassium is still potassium.

Sulphur is still sulphur.

At the same time, those nutrients exist inside an incredibly complex living system involving:

• roots;
• bacteria;
• fungi;
• organic matter;
• carbon;
• minerals;
• moisture;
• oxygen;
• pH; and
• countless chemical and biological interactions.

So for us, the more useful question is:

How do we get nutrition and biology working better together?

That's a big part of what Bio Charge is trying to explore.

Bio Charge isn't built around the idea that farmers should suddenly abandon conventional fertility programmes.

Quite the opposite.

We're interested in helping build stronger soil and plant systems around the nutrients farmers are already applying.

Our formulations use combinations of ingredients such as:

• fish hydrolysate;
• biochar;
• seaweed;
• molasses;
• humic and fulvic compounds;
• amino compounds;
• trace elements; and
• minerals.

Different products use those ingredients for different purposes.

For example, Bio Charge Boost combines fish hydrolysate, charged biochar, seaweed and molasses as a biological soil foundation treatment.

Bio Charge Fungal Feeder uses fish hydrolysate, molasses and charged biochar as part of a formulation aimed at supporting fungal and wider root-zone biological activity.

Then we have products such as Bio Charge MAX NPKS, which deliberately bring the two worlds together — supplying actual NPKS nutrition on top of a biological base.

That's a good example of why we don't see fertiliser and biostimulants as mutually exclusive.

There isn't one universal recipe.

“Biostimulant” describes what a product is intended to do rather than one specific ingredient.

Different formulations can contain very different materials.

Here are some of the ingredients we're particularly interested in.

Fish hydrolysate is produced by breaking down fish material while retaining a broad range of naturally occurring compounds.

Depending on the product and manufacturing process, fish hydrolysates can contain:

• organic nitrogen;
• amino compounds;
• peptides;
• minerals; and
• other marine-derived compounds.

We use fish hydrolysate as both a nutritional and biological input within several Bio Charge formulations.

It isn't there because “fish is magic”.

It's there because it provides a broad organic input that can form part of the food and nutrient environment around soil biology and plants.

We'll dig much further into fish hydrolysate in another article.

Molasses is much simpler.

It is a readily available source of carbon and sugars.

And carbon matters because microorganisms need energy.

Soil biology isn't powered by good intentions.

Microorganisms require carbon compounds and other resources to grow, reproduce and carry out the processes happening around the root zone.

Molasses provides one form of readily available carbon within some of our formulations.

Different forms of carbon behave differently. Molasses provides a readily available carbon source within selected Bio Charge formulations.

Biochar plays a very different role.

Rather than being only an easily consumed carbon source, biochar is a relatively stable, highly porous carbon material.

Its physical structure gives it an enormous internal surface area.

We're interested in that structure because of the environment it can provide around water, nutrients and biological activity.

We recently took a much deeper look at this in our article:

What Is Biochar? Why We Use It in Our Liquid Biostimulants

Again, biochar isn't a silver bullet.

It's another piece of the puzzle.

Biochar provides a very different form of carbon from readily available sources such as molasses.

Seaweed extracts have become a common component of plant biostimulant research and formulations internationally.

They contain a complex mixture of naturally occurring compounds rather than simply being an NPK fertiliser.

For Bio Charge, seaweed sits alongside our other biological and plant-support ingredients as part of the wider formulation.

The important point is that we're not looking at any one ingredient in isolation.

We're interested in what happens when complementary inputs are brought together.

Seaweed extracts are widely used within biostimulant formulations and contain far more than a simple NPK analysis can describe.

Amino acids are fundamental components of proteins and are involved throughout plant and biological systems.

Protein hydrolysates are also recognised internationally as an important category of non-microbial plant biostimulant.

Again, that doesn't mean adding amino acids automatically guarantees a particular result.

Formulation, application rate, timing, crop, soil conditions and the wider nutrient programme all matter.

This is something we think gets lost when agricultural products are marketed as miracle fixes.

Another common misconception is that every biostimulant is simply a bottle full of live bugs.

It isn't.

Some biostimulants are microbial and contain selected microorganisms.

Others are non-microbial biostimulants containing materials such as seaweed extracts, protein hydrolysates, humic substances or other compounds intended to influence plant and root-zone processes.

Bio Charge's approach is heavily focused on supporting the biological environment.

That includes providing carbon-rich and organic inputs that can interact with the existing biology already present within the soil system.

Healthy agricultural soil already contains an enormous biological community.

The question is what environment we're creating for it.

It's easy to think about farming almost entirely above the ground.

Grass.

Leaves.

Yield.

Animals.

Harvest.

But beneath every hectare is an incredibly complicated ecosystem.

Plant roots release compounds into the rhizosphere — the narrow region of soil directly influenced by the roots.

Microorganisms interact with those roots.

Organic material is broken down.

Nutrients change form.

Minerals dissolve and react.

Water moves.

Gases exchange.

Carbon is constantly cycled.

That's why we keep coming back to the same idea at Bio Charge:

More from every hectare starts below ground.

If we can support a better-functioning root-zone environment, we believe that's worth investigating.

The root zone is where biology, water, nutrients, minerals and plants all meet.

This is another important distinction.

When we talk about nutrient efficiency, we're not saying:

“Stop fertilising.”

We're asking:

How much value are we getting from every kilogram of nutrient that goes onto the farm?

If you apply a nutrient, ideally you want as much of that investment as practical contributing to productive growth rather than being lost, immobilised or unavailable when the plant needs it.

That's why nutrient efficiency is such an interesting area.

Sometimes the answer may be the right fertiliser.

Sometimes it's better timing.

Sometimes it's soil pH.

Sometimes it's moisture.

Sometimes it's rooting.

Sometimes biological processes may play a part.

Usually, it's a combination of factors.

There is rarely one lever.

This is probably one of the first questions farmers should ask.

And the answer is:

Not automatically — and that's not how we think about them.

If your farming system has a genuine nutrient requirement, a bottle labelled “biostimulant” doesn't magically make that requirement disappear.

Plants still need adequate nutrition.

A biostimulant should be looked at according to what that particular formulation is designed to do.

Some contain very little conventional plant nutrition.

Others contain meaningful nutrient levels as well as biological components.

That's why the label, analysis and intended purpose matter.

For example, Bio Charge Boost and Fungal Feeder play very different roles from MAX NPKS.

One is primarily about the biological/root-zone environment.

The other deliberately provides NPKS nutrition as well as the Bio Charge biological base.

Different tools for different jobs.

This is worth stressing.

Just because two products both use the word “biostimulant” doesn't mean they are remotely identical.

One might be based primarily on seaweed.

Another might contain humic substances.

Another might contain microbes.

Another might be based on protein hydrolysates.

Another might combine several of these.

They may also have completely different:

• concentrations;
• manufacturing methods;
• application rates;
• timings;
• target crops;
• application methods; and
• intended outcomes.

So we don't think it's particularly useful to make blanket statements such as:

“Biostimulants work.”

or

“Biostimulants don't work.”

That's a bit like saying fertiliser works or doesn't work without specifying which fertiliser, at what rate, on which soil, for which crop and for what purpose.

The product and the situation matter.

There's growing scientific interest in plant biostimulants, but that doesn't mean every claim made in the marketplace is automatically proven.

Scientific research continues to investigate areas such as nutrient-use efficiency, plant responses to environmental stress and root-zone processes.

It also identifies plenty of knowledge gaps.

That's important.

We're interested in biological agriculture, but we're equally interested in being realistic about what is known, what is still being investigated and what needs to be demonstrated in the field.

A flashy label doesn't replace evidence.

Neither does the word “natural.”

Ultimately, farmers need products and programmes that make practical and economic sense.

This is probably the biggest point we want to make.

We don't believe better farming is going to come from finding one miracle ingredient.

Not biochar.

Not fish.

Not seaweed.

Not molasses.

Not nitrogen.

Not phosphorus.

Not a particular bacterium or fungus.

Each one is simply another component within a much larger system.

Agriculture is about managing the interactions between:

soil + biology + nutrition + plants + animals + climate + management.

That's complicated.

But it's also where some of the biggest opportunities are.

Bio Charge exists because we think there is still a huge amount to learn about how we can make those pieces work better together.

Bio Charge formulations are designed around the idea that soil biology and plant nutrition don't need to sit in separate camps. Explore our biological and nutritional inputs for New Zealand farming systems.

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