Are you using a smart coating for your urea?

Co-authored: Elle Scannell, Research & Development Scientist & Dr Timothy Hughes, Research & Development Chemist, Laboratory Manager

When your bottom-line matters and every nutrient counts, are you confident your nitrogen (N) is staying where it should, in your soil?
As pressure builds to farm more efficiently and sustainably, fertiliser decisions have never been more important. In this article, we explore N retention, the volatilisation of urea, and how Green Urea NV®, a smart, Australian made N solution, has been proven to reduce volatilisation, protect your investment, and support long-term productivity in real-world conditions.

If you have planted winter crop, now is the perfect time to plan your N topdressing strategy. N is essential for plant growth and development but keeping it in a plant-available form can be challenging.1,2 Urea is highly volatile, and up to 33% of applied N can be lost through ammonia volatilisation, according to IPF’s most recent trials.

An alternative to standard urea is Green Urea NV®, IPF’s enhanced efficiency fertiliser (EEF), featuring a proven urease inhibitor. This patented formulation slows the conversion of urea to ammonia, helping to keep more N in the soil.

Image 1: Ammonia gas capture chambers in use in the field in Victoria.

Source: IPF R&D Agronomist, Dr Robert Impraim, 2024.

How Green Urea NV works

Urease inhibitors work by delaying the hydrolysis of urea through suppressing the activity of the urease enzyme in soil, which prevents the rapid breakdown of urea into ammonia gas allowing rainfall or irrigation to move N deeper into the soil before it escapes as ammonia gas.3 This minimises N loss through volatilisation when fertiliser is surface applied (top-dressed).

Longevity and consistent performance

Green Urea NV uses N-(n-butyl)thiophosphoric triamide (NBPT), the most widely recognised urease inhibitor. While NBPT typically breaks down quickly after coating, IPF’s patented formulation ensures consistent performance for at least six months.

The low-rate, non-volatile coating penetrates deep into the granule, reducing clumping, maintaining better flowability than other brands, and enhances product stability during storage, handling, and distribution.

A safer solution

As NBPT is a solid, to apply it to urea granules, IPF uses a co-solvent system of tetramethylene sulphone (sulfolane) and triethanolamine (TEA) to dissolve the NBPT.

Sulfolane is classified as a Green Solvent, non-toxic, non-volatile, biodegradable, and sustainable.4,5 It does not accumulate in the soil or body and biodegrades even faster in nutrient-rich environments, making it ideal for agricultural applications.7-11

TEA, while not classified as a Green Solvent due to its non-renewable source, is also biodegradable, low in toxicity, and non-volatile.12,13 It does not bioaccumulate and is widely used in consumer products such as cosmetics, laundry detergents, dishwashing liquids, and general cleaners.11,14 TEA is safely used in over 3,700 cosmetic products, many of which are “leave-on” applications, at concentrations far higher than those used in Green Urea NV.13

Together, sulfolane and TEA provide a safe, stable, and effective delivery system for NBPT, supporting both performance and environmental safety.

Tested in Australian soils, for Australian farmers

IPF’s Research and Development, and Agronomy teams are committed to delivering solutions backed by Australian research. Green Urea NV has been tested in over 20 different Australian soils across cropping, broadacre, pasture, and horticulture. Trials have shown an average 78% reduction in N losses and an estimated $50/ha net saving when compared to uncoated urea.

As a wholly Australian-owned formulation, Green Urea NV is designed to meet local soil conditions, compliance requirements, and supply chain needs, ensuring product availability, efficacy, and safety for Australian farmers.

Staying ahead of evolving regulations

As global attention intensifies on reducing agricultural emissions, several countries have introduced stricter regulations around N fertiliser use, particularly targeting uncoated urea. In Europe, ambitious ammonia reduction targets have driven mandatory adoption of urease inhibitors.15,16

For instance, in England, uncoated urea can now only be applied between 15 January and 31 March, and any use outside this window must include a urease inhibitor.17 Similarly, under Germany’s Fertiliser Act 2017, all urea fertilisers must either contain a urease inhibitor or be incorporated into the soil within four hours of application.18

In anticipation of similar regulatory shifts in Australia, IPF has proactively developed Green Urea NV to provide a compliant, effective, and locally validated solution. It not only aligns with international best practices but also offers proven performance under Australian conditions. Backed by local research and field testing, Green Urea NV equips growers with a reliable and forward-looking choice that supports both productivity and compliance.

Summary

  • Reduces N volatilisation and keeps more N in your soil
  • Proven shelf life, remains effective for 6+ months in storage
  • Low application rate with minimal clumping and excellent handling
  • Uses greener, safer solvents to support environmental safety
  • 100% Australian-made, tested, and tailored for local farming systems.

Further information

For more information, feel free to contact, Technical Agronomist, Lee Menhenett at lee.menhenett@incitecpivot.com.au or +61 412 565 176.

References

  1. Shipkowski, K. A., Cora, M. C., Cesta, M. F., Robinson, V. G., Waidyanatha, S., Witt, K. L., … & Blystone, C. R. (2021). Comparison of sulfolane effects in Sprague Dawley rats, B6C3F1/N mice, and Hartley guinea pigs after 28 days of exposure via oral gavage. Toxicology Reports, 8, 581–591. https://doi.org/10.1016/j.toxrep.2021.03.003
  2. Pan, B., Lam, S. K., Mosier, A., Luo, Y., & Chen, D. (2016). Ammonia volatilization from synthetic fertilizers and its mitigation strategies: A global synthesis. Agriculture, Ecosystems & Environment, 232, 283–289. https://doi.org/10.1016/j.agee.2016.08.019
  3. Hu, Y., & Schmidhalter, U. (2021). Urease inhibitors: Opportunities for meeting EU national obligations to reduce ammonia emission ceilings by 2030 in EU countries. Environmental Research Letters, 16, 084047. https://doi.org/10.1088/1748-9326/ac16fe
  4. Doble, M., & Kruthiventi, A. K. (2007). Alternate solvents. In Green chemistry and engineering (pp. 93–104). Academic Press. https://doi.org/10.1016/B978-012372532-5/50009-4
  5. Usman, M., Cheng, S., Boonyubol, S., & Cross, J. S. (2023). Evaluating green solvents for bio-oil extraction: Advancements, challenges, and future perspectives. Energies, 16(15), 5852. https://doi.org/10.3390/en16155852
  6. Byrne, F. P., Jin, S., Paggiola, G., Petchey, T. H., Clark, J. H., Farmer, T. J., … & Sherwood, J. (2016). Tools and techniques for solvent selection: Green solvent selection guides. Sustainable Chemical Processes, 4, 1–24. https://doi.org/10.1186/s40508-016-0051-z
  7. Waidyanatha, S., Black, S. R., Blystone, C. R., Patel, P. R., Watson, S. L., Snyder, R. W., & Fennell, T. R. (2020). Disposition and metabolism of sulfolane in Harlan Sprague Dawley rats and B6C3F1/N mice and in vitro in hepatocytes from rats, mice, and humans. Xenobiotica, 50(4), 442–453. https://doi.org/10.1080/00498254.2019.1604965
  8. Health Canada. (2020). Screening value for sulfolane in drinking water. https://www.canada.ca/content/dam/hc-sc/documents/services/health/publications/healthy-living/drinking-water-screening-value-sulfolane/drinking-water-screening-value-sulfolane.pdf
  9. Safe Work Australia. (n.d.). Hazardous chemical information: Sulfolane. https://hcis.safeworkaustralia.gov.au/HazardousChemical/Details?chemicalID=4413
  10. EHS Support. (2021). Triethanolamine – Environmental and human health risk assessment. https://www.santos.com/wp-content/uploads/2021/08/Triethanolamine-July-2021.pdf
  11. Đorđević, B. S., Kostić, M. D., Todorović, Z. B., Stamenković, O. S., Veselinović, L. M., & Veljković, V. B. (2023). Triethanolamine-based deep eutectic solvents as cosolvents in biodiesel production from black mustard (Brassica nigra L.) seed oil. Chemical Engineering Research and Design, 195, 526–536. https://doi.org/10.1016/j.cherd.2023.03.034
  12. Fiume, M. M., Heldreth, B., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., … & Andersen, F. A. (2013). Safety assessment of triethanolamine and triethanolamine-containing ingredients as used in cosmetics. International Journal of Toxicology, 32(3_suppl), 59S–83S. https://doi.org/10.1177/1091581813504216
  13. Khoraamabadi-Zad, A., Azadmanesh, M., Karamian, R., Asadbegy, M., & Akbari, M. (2014). Triethanolamine as an inexpensive and efficient catalyst for the green synthesis of novel 1H-pyrazolo[1,2-a]pyridazine-5,8-diones under ultrasound irradiation in water and their antibacterial activity. RSC Advances, 4(88), 47721–47725. https://doi.org/10.1039/C4RA06528D
  14. ECHA. (n.d.). List of fertilisers – Annex I. European Chemicals Agency. https://echa.europa.eu/fertilizer-list-ann-1-f
  15. Carbon Brief. (2024, July 9). Q&A: How Denmark plans to tax agriculture emissions to meet climate goals. https://www.carbonbrief.org/qa-how-denmark-plans-to-tax-agriculture-emissions-to-meet-climate-goals/
  16. Willis, E. (2024, April 17). How do new rules on urea use in England affect farmers? AHDB News. https://ahdb.org.uk/news/how-do-new-rules-on-urea-use-in-england-affect-farmers
  17. FAO. (n.d.). FAOLEX Database: Danish Order on fertilisers and soil improvers. https://www.fao.org/faolex/results/details/en/c/LEX-FAOC084813/