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

The hot weather has arrived, and horticultural crops are now growing and producing strongly. However, for many growers, this time of year also brings the return of saline irrigation water and salt stress in the soil.

After a dry winter across much of the country, there has been little opportunity for salts to leach from the root zone, leading to a gradual build-up that limits water availability and slows plant growth. Salinity remains one of the major challenges in Australian horticulture.

When salt levels are high, water becomes harder for plants to absorb, even when the soil appears moist. This “physiological drought” reduces both water and nutrient uptake, leading to poor growth and yield losses.

It is estimated to causing an estimated $519 million in lost agricultural production each year.

How Trigger® helps

Trigger, with its unique formulation and easy application, offers a practical solution to manage these effects. It works by tying up sodium and other salts in the soil, reducing their impact on crop growth and improving soil structure. This helps lower salinity stress, enhances water absorption, and creates a healthier root environment, allowing crops to access the nutrients they need for stronger, more consistent growth.

Its humic components interact with soil cations such as sodium, potassium, and calcium to form stable complexes that lower the concentration of soluble salts in the soil solution. In saline–alkaline soils, Trigger also helps neutralise alkaline substances, improving soil structure and reducing sodicity.

At the plant level, Trigger supports better tolerance to salinity by activating natural growth and defence pathways, enhancing cell membrane stability, and helping plants maintain water absorption under stress. This supports stronger root and shoot development, even under saline conditions.

While humic acids primarily bind to positively charged ions, Trigger can also help alleviate chloride-related salinity issues indirectly. By improving soil structure and drainage, balancing cations such as sodium and calcium, and strengthening root membranes, Trigger promotes more efficient leaching of excess chloride and helps plants regulate its uptake. This combined effect contributes to healthier soils, reduced salinity stress, and greater crop resilience under challenging growing conditions.

Trigger® salinity trial

IPF conducted a glasshouse trial to determine the effect of Trigger application on Na+ and Cl- uptake and wheat growth. Pots containing 5 kg of soil each were sown to wheat. The treatments applied were:

  • Soil only (control)
  • NPKS @ 100 kg N/ha 
  • Trigger @ 20 kg/ha
  • Trigger @ 40 kg/ha
  • NPKS @ 100 kg N/ha + Trigger @ 20 kg/ha
  • NPKS @ 100 kg N/ha + Trigger @ 40 kg/ha

Treatments were applied in both saline soil (soil that received NaCl solution) and non-saline soil (soil that received distilled water).

Across all treatments, wheat growth was suppressed (smaller plants) in saline soil (Figure 2). In both saline and non-saline soils, NPKS + Trigger (40 kg/ha) increased plant biomass compared to the other treatments, while Trigger alone showed no significant effect relative to the soil-only treatment (Figures 1 and 2).

This outcome is consistent with Trigger’s mode of action: it helps the plant keep absorbing water and nutrient availability, helping plants maintain growth under salt stress when nutrients are present. These findings also highlight the importance of application rate under saline conditions, indicating that a minimum of 40 kg/ha is required to achieve a measurable effect.

Figure 1. Non saline soil (left): A. Soil only; B. NPKS only; C. NPKS + Trigger @ 20 kg/ha; D. NPKS + Trigger @ 40 kg/ha. Saline soil (right): E. Soil only; F. NPKS only; G. NPKS + Trigger @ 20 kg/ha; H. NPKS + Trigger @ 20 kg/ha; in saline soil (plants were irrigated using 20-100 mM NaCl solution). Source: Incitec Pivot Fertiliser.

Figure 2. Total dry aboveground biomass of wheat in saline and non-saline soil. Bars represent standard error of mean (n = 3). Source: Incitec Pivot Fertilisers.

Plants treated with Trigger alone showed reduced sodium (Na⁺) uptake, and this effect was also observed when Trigger was applied with NPKS, resulting in lower Na⁺ accumulation in wheat compared with NPKS on its own. These reductions in Na⁺ uptake support the role of Trigger in improving ion balance under saline conditions (Figure 4).

Figure 3. Sodium (Na⁺) concentration in wheat plant tissues (%) across six nutrient treatments: Soil Only, NPKS (100 kg N/ha), Trigger @ 20 kg/ha, Trigger @ 40 kg/ha, NPKS + Trigger @ 20 kg/ha, and NPKS + Trigger @ 40 kg/ha. The bar graph shows that both Trigger alone and Trigger combined with NPKS reduced Na⁺ accumulation compared with NPKS on its own, with the strongest reduction observed at the 40 kg/ha rate. This highlights Trigger’s role in supporting ion balance and mitigating sodium uptake under saline conditions. Source: Incitec Pivot Fertilisers.

Key Points managing salinity with Trigger

  • Salinity limits water and nutrient uptake, reducing yield and plant growth.
  • Trigger binds sodium and other salts:
    • improving soil balance and structure.
    • enhances water movement and leaching of excess salts from the root zone.
    • strengthens root membranes, helping plants tolerate saline conditions.
    • supports healthier soils and more resilient, productive crops.
  • Consider liquid Trigger as an option in irrigated systems. Its clean, low-sediment formulation ensures smooth equipment performance while maintaining high compatibility with most fertilisers, giving growers a practical tool to manage salt stress in sensitive crops.

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

Li G, Shan Y, Nie W, Sun, Y, Su L, Mu W, Qu Z & Yang, T. (2025). Humic acid improves water retention, maize growth, water use efficiency and economic benefits in coastal saline-alkali soils. Science of the Total Environment.  https://doi.org/10.1016/j.agwat.2025.109323

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.

Ouni, Y., Ghnaya, T., Montemurro, F., Abdelly, C., & Lakhdar, A. (2014). The role of humic substances in mitigating the harmful effects of soil salinity and improving plant productivity. Laboratoire des Plantes Extrêmophiles, Centre de Biotechnologies de Borj Cedria, Tunisia, and Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Italy.