Co Authors: Natalia Gomez – IPF’s Farming Specialist, Farming Services, and Robert Impraim – IPF’s Research & Development Agronomist, Research & Development

In today’s high-input systems, growers need to make every kilogram of fertiliser count. Nutrient loss or imbalance can significantly reduce both yield and return on investment. This is most challenging in:

  • low-CEC soils, where nutrients are easily lost before the crop can use them.
  • heavy soils, where strong fixation can make key elements unavailable.
  • low-PBI soils, where phosphorus is quickly leached or tied up; and
  • sandy soils, where leaching losses are often high, among others.

A humic acid like Trigger®, in combination with fertiliser, can help hold essential nutrients in the root zone for longer. It also helps release nutrients that have been fixed in the soil, such as phosphorus, making them available for plant uptake.

With a cation exchange capacity (CEC) of around 450 meq/100 g

How Trigger improves nutrient uptake and plant efficiency

Humic acids play a vital role in improving how plants access and utilise nutrients. The reactive functional groups in Trigger form natural bonds with positively charged metals such as calcium, iron, zinc, and copper, preventing them from leaching or becoming locked up in the soil. This keeps nutrients in a plant-available form for longer and helps them move more efficiently into the root zone, where the plant can use them.

When these mechanisms are active, products like Trigger can improve the plant’s internal nutrient balance, supporting healthier and more vigorous growth. It can also stimulate natural growth hormones such as auxins and cytokinins, which are key to root elongation, vegetative development, and stress resilience. Together, these effects translate into stronger plants with improved nutrient use efficiency and greater productivity.

With its high cation exchange capacity, Trigger creates a nutrient-rich microenvironment around each granule. Much like a tea bag releasing its compounds when wet, Trigger activates every time it comes into contact with moisture, forming a high-CEC zone. This root-zone environment holds essential nutrients such as calcium, magnesium, and potassium in a plant-available form for longer, supporting improved nutrient uptake and overall soil fertility.

Trigger and phosphorus

When we talk about phosphorus, one of the most expensive fertilisers on the market, we know that its availability in the soil can decline rapidly due to fixation. This process occurs when phosphorus reacts with aluminium and iron ions in acidic soils, or with calcium ions in alkaline soils, forming insoluble compounds that plants cannot absorb. Trigger helps overcome this problem by dissolving bound phosphates and increasing phosphorus mobility. It also forms stable complexes with Fe³⁺, Al³⁺, and Ca²⁺ ions, preventing them from reacting with phosphate. This keeps phosphorus in a plant-available form for longer, reducing fixation and improving uptake efficiency.

Yield improvement with Trigger

An IPF demonstration in a commercial cabbage field in Bacchus Marsh, Victoria quantified the effect of Trigger applied with NPKS fertiliser. Treatments were applied at a rate of 100 kg N/ha, in a range of combinations:

  • NPKS compound fertiliser
  • Trigger – NPKS blend of 5%
  • Trigger – NPKS blend of 15%
  • Farmer practices (NPKS + Organic matter)
  • Granulated chicken manure + NPKS (B5)

Results showed that cabbage biomass increased by 15–18% when Trigger was added to NPKS, compared with using NPKS on its own (Figure 1). When measured against the farmer practice of NPKS plus organic matter, the Trigger treatment still achieved a 9–16% yield lift (Figure 1). These results show that Trigger can boost crop productivity by creating a more favourable root environment and improving access to applied nutrients, leading to stronger, more consistent growth.

Figure 1. Average fresh biomass of cabbage heads. Bars represent standard error of mean (n = 3).

Trigger creates a nutrient-rich microenvironment around each granule with a naturally high exchange capacity. This localised zone holds essential nutrients such as calcium, magnesium, potassium, and phosphorus in plant-available forms for longer, reducing losses through leaching or fixation. When applied with fertilisers, Trigger establishes ideal conditions for those nutrients to stay available and be absorbed more efficiently by the crop. This improved nutrient use leads to stronger root systems, more uniform growth, and greater biomass accumulation. In high-demand crops like cabbage, this effect translates directly into higher productivity and more resilient growth under varying soil conditions.

Key points

  • Nutrient losses through leaching and fixation reduce fertiliser efficiency and yield.
  • Trigger creates a high-CEC microenvironment around each granule, keeping key nutrients like P, K, Ca, and Mg available for longer.
  • Improves nutrient uptake, root growth, and overall crop efficiency when used with fertilisers.
  • Demonstrations in cabbage crops showed yield increases of up to 16%, highlighting Trigger’s role in improving productivity and nutrient use.

Further information

For more information on Trigger, feel free to contact IPF’s Farming Specialist, Natalia Gomez, at natalia.gomez@incitecpivot.com.au or +61 427 232 982.

References

Wang, X. J., Wang, Z. Q., & Li, S. G. (1995). The effect of humic acids on the availability of phosphorus fertilisers in alkaline soils. Soil Use and Management, 11(2), 99–102. https://doi.org/10.1111/j.1475-2743.1995.tb00503.x

Ampong, K., Thilakaranthna, M. S., & Gorim, L. Y. (year). Understanding the role of humic acids on crop performance and soil health. Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.