In 2024, Summit Fertilizers ramped-up its research into Enhanced Efficiency Fertilizers (EEFs) with the promising trends of the previous season further reinforced.
Eighteen trials over two seasons spread across WA’s grain growing regions now show that two products:
●N-Shield NBPT; and,
●N-Shield DUAL
work as expected, as an insurance policy against conditions that result in nitrogen loss through volatilisation or after nitrification, or both.
It is an outcome that has the double benefit of being better for growers and the environment.

The EEFs explained
N-Shield NBPT is a Summit Fertilizers product coated on urea containing NBPT, N-(n-Butyl)thiophosphoric triamide, a compound that directly interrupts urease activity on regular urea to prevent volatilisation, thus reducing losses of ammonia gas.
N-Shield DUAL is also coated on urea, combining NBPT with Dicyandiamide (DCD). DCD slows the nitrification process, preventing losses through leaching under certain conditions (see diagram below).The trials included urea and UAN as a control treatment with the N rate consistent across all treatments.
N-Shield NBPT was applied post-emergent, whilst N-Shield DUAL was applied at seeding and post-emergent.

2024 results
Many trials did not experience environmental conditions that would lead to excessive N losses. As expected, the benefits were not observed at these sites.
The Mingenew trial however did show significant responses to both N-Shield NBPT (Figure 3) and N-Shield Dual (Figure 4).
This trial highlighted that when weather conditions are conducive to N losses, there can be significant yield benefits from these EEFs.

Where do they fit?
Where these products have a potential fit will really come down to how growers assess the risk, cost
and the potential benefit.
Protection against nitrogen loss would be particularly beneficial where urea is spread early due to logistics rather than due to imminent rainfall.
N-Shield NBPT has a good fit for early season urea applications when light and patchy rainfall is likely, as it will help protect the urea until sufficient soil moisture is achieved.
N-Shield DUAL has a better fit later in the season where there is a relatively full soil moisture profile. The DCD component will safeguard against leaching losses, with NBPT offering protection against any light or patchy rain events.
It is important to note, there was no significant yield decrease to using either product, demonstrating N is released once the protection has ended due to sufficient rainfall.