Why does modern agronomy require flexibility beyond traditional fixed fertilizer formulations?

Global fertilizer supply operates within a highly structured system. Phosphate and nitrogen fertilizer granules are manufactured in large facilities, often in one part of the world, then shipped across oceans, unloaded at ports, stored in bulk and finally distributed inland to farms. The infrastructure is designed for scale, efficiency and reliability. Once those fertilizers leave the manufacturing plant, their composition is largely fixed.

Modern agronomy, however, is not fixed.
Soil conditions vary from region to region and even paddock to paddock. Crop rotations and seasonal rainfall change nutrient demand. Furthermore, agronomists increasingly recommend precise micronutrient additions—zinc, copper, manganese, magnesium or molybdenum, to name a few—tailored towards specific soil deficiencies. Yet the base fertilizer manufacturing system and supply chain cannot be reconfigured each season to meet those changing requirements.

This creates a structural gap between how fertilizer is produced and how it is needed in the field.

Crommelin AgriCoatings bridges the rigid global fertilizer supply system and the increasingly dynamic agronomic requirements by transforming traditional granular fertilizer coatings into nutrient delivery platforms.

Rather than attempting to redesign fertilizer granulation or interrupt established logistics, Crommelin works within the existing supply chain, often at a fertilizer business’s point of distribution. Once fertilizer reaches the distribution stage, the coating becomes the final component applied before the product moves to the farm.

“That coating can either be a simple protective film to suppress dust and reduce caking, or it can be engineered to carry additional value,” says Hein de Villiers, director. “We chose the latter.”

By applying high-solids micronutrient coating formulations directly onto each granule during a blending process at distribution, Crommelin ensures every particle has both its base NPK content and the targeted micronutrient additions specified by agronomic advice. The underlying fertilizer properties remain unchanged as storage stability, flowability and handling characteristics are preserved. The change is that the nutrient profile becomes more precise.

In this way, the coating shifts from a surface preservative to a delivery mechanism—introducing nutrient flexibility into a mature supply system without disrupting how growers store, transport or apply fertilizer.

Engineering Consistency at Commercial Scale

How can micronutrient coatings improve nutrient consistency across large-scale fertilizer distribution systems?

The advantage of integrating micronutrients on the surface of each granule becomes clear once fertilizer blending is considered.

When micronutrients such as zinc or copper are required at rates measured in fractions of a percent, doing that through bulk blending distribution becomes a matter of probability. Even well-calibrated systems can struggle to ensure that every tonne—and every paddock—receives a consistent level of trace elements.

At low throughputs, a small variation may be manageable but during seasonal volumes, small inconsistencies can amplify through Western Australia’s supply chain. Companies can quickly find themselves with stock shortages or an over-supply of unwanted product at the end of the season.

Applying micronutrients through a high-solids coating improves nutrient distribution and simplifies fertilizer blend consistency. Instead of relying on blend homogeneity, nutrients are physically attached to each NPK granule in a blending process at distribution. The result now becomes a particle-level guarantee rather than a statistical mix.

The careful design of the coating ensures that the blending process does not affect a fertilizer company’s operations. Fertilizer out-loading speeds—which can be 200-300 t/hr in Western Australia—remain unchanged, and dispatch schedules are unaffected. The companies can simplify their storage with standard fertilizer grades and still offer a greater complexity of products.

“The supply chain is built for volume,” says de Villiers. “What we’ve done is introduce flexibility without slowing it down.”

Engineering Under Commercial Conditions

What engineering challenges must fertilizer coatings overcome during storage, blending, and field application?

A fertilizer coating is engineered for harsh conditions. It must quickly coat and dry in a commercial blending plant, withstand months of bulk storage and remain stable in field conditions.

Crommelin’s micronutrient coatings carry close to 60 percent micronized nutrient powder within a liquid phase. At that concentration, stability becomes critical, for if the particles are not fully dispersed and wetted, they settle in storage tanks. If settlement occurs, nutrient content becomes inconsistent before the product even reaches the blender.

“That’s where formulation discipline matters,” explains de Villiers. “If you don’t control powder dispersion properly, it won’t stay uniform.”

To prevent this, Crommelin uses high-shear and ultra-high-shear in-line emulsification systems. These processes break apart agglomerates, fully wet individual particles to maintain suspension stability for extended storage periods. The coating remains consistent for months before application.

However, maintaining stability is only part of the challenge. The coating also needs to have the right flow characteristics. In commercial blending operations in Western Australia, high-viscosity materials, can slow liquid delivery and reduce loading operations. If the viscosity is too low, the liquid coating is likely to be absorbed into the surface of the fertilizer granules rather than spreading evenly over them.

de Villiers explains that achieving the correct balance is crucial for them. The coating must be fluid enough to flow efficiently through the blending system, yet viscous enough to remain on the granule surface rather than being absorbed.

Careful manipulation of rheology determines how the coating spreads over the granule. Once introduced into the blender, the coating has seconds to distribute over the granules. A single ton of two- to four-millimeter granules represents close to 800 to 1,000 square meters of surface area. Only part of that surface is directly contacted with the coating at application, and the rest depends on granule-to-granule contact as material tumbles. Within about 50 seconds, the liquid forms a stable, cured, film over the granule. At that stage, it is robust enough to pass through elevators, screens and transport systems before entering bulk storage on farms.

The value of this engineering discipline is that it ensures the amount of nutrients each granule carries remains consistent from the blending and distribution plant all the way to the field.

From Attachment to Nutrient Availability

How can fertilizer coatings influence nutrient availability and soil interactions after field application?

Once Crommelin solved the mechanical challenge of suspending micronized powders and achieving reliable curing, a new question emerged. ‘If the coating can consistently carry nutrients, what role can it play once the granule is in the soil?’

This thinking has evolved the coating platform beyond simple nutrient attachment.

The liquid system now incorporates chelating agents, compatibilizers, metabolizers and selected biostimulants. These additions are designed to influence how micronutrients behave at the granule–soil interface.

The coating can also improve nutrient availability. When phosphate-based fertilizers such as monoammonium phosphate (MAP) and diammonium phosphate (DAP) are placed in the soil, the phosphate can interact with metal ions present and become unavailable (or locked up) to the plant. By moderating those interactions at the moment of soil contact, with coating additives, the phosphate becomes more available, improving early plant development.

The objective is not to alter the fertilizer chemistry, but to influence how nutrients remain accessible within the soil environment.

So, what began as a logistical solution to a structured fertilizer supply chain has evolved into a functional delivery system aimed at improving crop and soil health. Crommelin applies coating science not only to improve handling performance but also to influence nutrient behavior at the soil interface.

Discipline Before Innovation

At Crommelin AgriCoatings, innovation begins with overcoming the complex operational constraints of fertilizer blending, distribution and storage systems.

Every additive is evaluated within the realities of a high-solids coating system operating at commercial scale. Formulations must remain stable in storage for extended periods, maintain suspension integrity under temperature fluctuation and pump consistently into high-speed blending systems. Once applied, the coating must cover across granules and cure within a very short period. If any of these parameters fall outside tolerance, the formulation does not proceed.

“Agronomic potential alone is not sufficient,” explains de Villiers. “A component may enhance soil interaction or nutrient availability, but if it compromises rheology, storage stability or curing performance, it is excluded. Reliability within the supply chain remains the first requirement.”

The approach reflects a clear principle. The fertilizer granule remains the backbone of nutrient delivery to a crop Crommelin’s role is to refine what happens at the surface of the granule, while working within the requirements of commercial fertiliser distribution systems.

This way, Crommelin AgriCoatings positions surface science to add agronomic flexibility without disrupting throughput, storage stability or distribution efficiency.