As seen in Farm Weekly, 30/04/2026

Fertiliser shortages are no longer a distant risk – they are a current constraint shaping farm decisions across Western Australia.

Volatility in global supply chains, rising input costs, and geopolitical pressures have forced growers to rethink how they maintain productivity without relying solely on synthetic fertilisers.

The challenge is real, but so is the opportunity to reset systems toward greater resilience.

One of the most practical and immediate levers available to growers is the strategic use of legumes.

Nitrogen-fixing species have always played a role in mixed farming systems, but their value is now front and centre.

The IH Seeds (Irwin Hunter & Co) range of legumes and pasture mixes provides a strong foundation for rebuilding soil nitrogen naturally while maintaining feed quality and system flexibility.

Legumes such as Serradella, Biserrula, clovers, and Vetch are not just rotational tools – they are nitrogen factories.

When managed well, they can contribute significant amounts of plant-available nitrogen to subsequent crops, reducing the need for synthetic inputs.

For example, well-established legume pastures can fix upwards of 50–150 kilograms of N/ha, depending on species, biomass, and seasonal conditions.

In a high-cost fertiliser environment, that represents a substantial saving.

IH Seeds' strength lies in offering species and blends suited to a wide range of WA soil types and rainfall zones.

Its mixes allow growers to tailor pasture systems that maximise ground cover, improve soil structure, and extend grazing windows.

Importantly, these mixes can be integrated into existing rotations without major system overhauls.

A well-timed legume phase can set up following cereal or oilseed crops with improved nitrogen supply and better soil health.

However, legumes alone are not a silver bullet.

Phosphorus and potassium remain critical for both pasture and crop performance.

This is where alternative fertiliser strategies come into play, particularly products like BioNPK Powder S.

BioNPK Powder S offers a different approach to nutrient management.

Rather than relying purely on highly soluble synthetic fertilisers, it combines essential macronutrients with a biological component designed to enhance nutrient availability and soil microbial activity.

This can improve nutrient use efficiency – something that becomes increasingly important when fertiliser inputs are limited or expensive.

In practical terms, integrating BioNPK Powder S into a system alongside legumes can create a complementary effect.

The legumes fix nitrogen, while BioNPK supports the availability of phosphorus, potassium and nitrogen, as well as stimulating the soil biology that underpins nutrient cycling.

This combination can help maintain productivity without the same reliance on traditional fertiliser programs.

From a management perspective, the key is planning.

Growers should be looking at rotations over a multi-year horizon, identifying where legume phases can be introduced or expanded.

Soil testing becomes even more critical, ensuring that any targeted fertiliser applications – whether conventional or alternative – are aligned with actual soil constraints.

There is also a financial dimension to consider.

While input costs for products like BioNPK Powder S and quality pasture seed are not insignificant, they should be evaluated against the rising cost of conventional fertilisers and the longer-term benefits of improved soil fertility.

In many cases, the return on investment comes not just from reduced fertiliser bills, but from more stable yields and improved system resilience.

The broader shift here is toward farming systems that are less exposed to external shocks.

Fertiliser shortages have highlighted the vulnerability of input-dependent models.

By contrast, systems that leverage biological processes – such as nitrogen fixation and enhanced microbial activity – offer a pathway to greater independence.

This is not about abandoning fertiliser altogether.

Rather, it is about using it more strategically, supported by legumes and biological inputs that do part of the heavy lifting.

IH Seeds' legume range and products like BioNPK Powder S provide practical tools for making that transition.

In a season where every input decision matters, the growers who adapt will be those who look beyond short-term fixes and invest in system-level solutions.

Legumes and biological fertilisers are not new ideas – but in the current environment, they may be the most relevant they have ever been.

Bio NPK Powder S: Key Benefits

  • More nutrients (N P K, Si)
  • Better soil structure
  • Higher water retention
  • Stress tolerance

Bacteria

  • Paenibacillus azotofixans (N fixation up to 50 kg/ha/yr)
  • Bacillus megaterium (P release up to 35 kg/ha/yr)
  • Bacillus mucilaginosus (K release up to 30 kg/ha/yr)
  • Bacillus subtilis and Bacillus licheniformis (stress tolerance)
  • Bacillus mycoides (Si release)

Fungi

  • Trichoderma viride (plant resilience)
  • Mycorrhizal fungi (plant nutrients, soil structure)

Contact your local farm supplier or Irwin Hunter & Co for more information regarding the extensive range of pasture seed and mixes.