Author: Dave McRae – Technical Agronomist Northern NSW

Getting your nitrogen (N) management right is essential for maximising cotton yields and limiting environmental losses, especially when the season doesn’t go to plan.

A recent comparison of two very different growing seasons highlights this. One with above average rainfall (2022–23) and another under much drier conditions (2024–25). Together they show how much difference a smart N strategy can make, and demonstrate the value of using enhanced efficiency fertilisers (EEFs) like eNpower® to improve crop performance and reduce nitrogen losses.

Field trials were carried out near Boggabri, NSW (2022–23), and Narrabri, NSW (2024–25).

Wet season with high N loss potential

The 2022-23 season saw substantial rainfall, particularly between June and November, a critical period for N uptake in cotton.

With a total of 331mm of rain during the fallow period and early in-crop, the potential for N loss through leaching and denitrification was significant.

Research indicates that the majority of N loss occurs during this early crop growth period when soil temperatures rise, moisture levels increase, and the crop’s N demand is low.

During this critical phase, eNpower was particularly effective in maintaining N in the ammonium form, which is less prone to loss compared to nitrate. Nitrate is more susceptible to denitrification under wet conditions.

Across this season, eNpower consistently provided higher yields across various N rates compared to untreated urea.

This is highlighted in Figure 1 which demonstrates the consistent yield advantage for cotton treated with eNpower. At the 200 kg/ha N rate, treated cotton yielded 13.53 bales/ha, compared to 12.88 bales/ha without eNpower. These results show the value of managing N efficiently during high rainfall periods.

Figure 1: Lint yield in response to nitrogen fertiliser application (2022-23) trial.

Source: Dave McRae, Technical Agronomist Northern NSW (2025)

Lowering risk of N loss in drier seasons

The 2024–25 season brought drier conditions, with just 144 mm of rainfall recorded between nitrogen application in mid-September and the end of November.

With limited rainfall, the risk of nitrogen losses through leaching or denitrification was lower, reducing the reliance on nitrification inhibitors like eNpower. Even so, the yield response remained positive. This suggests that eNpower can still deliver value in seasons with fewer weather-related challenges, particularly when used as part of a planned nitrogen strategy.

As shown in Figure 2, cotton treated with eNpower at 250 kg/ha total N (150 kg pre-plant + 100 kg in-crop) produced 16.1 bales/ha, outperforming the untreated crop, which yielded 15.59 bales/ha.

Figure 2: Lint yield in response to nitrogen fertiliser application (2024-25) trial.

Source: Dave McRae, Technical Agronomist Northern NSW (2025)

Consistent returns across seasons

Both the wet season (2022-23) and the drier season (2024-25) show that managing N with eNpower consistently improves cotton yields due to its ability to reduce N losses, especially early in the crop’s life. That’s when irrigations or rainfall can flush away nitrate, even before the crop gets a chance to use it.

Using eNpower as part of a broader N strategy helps keep more nitrogen in the soil for when the plant needs it, improving N use efficiency and supporting sustainable cotton production.

The take-home?

Seasonal variability doesn’t have to lead to uncertainty in yield outcomes. A well-considered nitrogen strategy, supported by products like eNpower, can help maintain productivity and extend nitrogen availability throughout the season.
Enhanced efficiency fertilisers (EEFs) offer growers and agronomists a practical tool for managing nitrogen more effectively under different seasonal conditions. Incitec Pivot Fertilisers continues to invest in research and product development to support sound, locally relevant nitrogen management decisions.

Further Information

For further information, please feel free to contact Dave McRae, IPF’s Technical Agronomist Northern NSW on david.mcrae@incitecpivot.com.au or 0477 987 321.