About Efficiency Enhancers

Fertilisers Efficiency Enhancers

The use of nitrogen is essential for agricultural production but only about 50% of nitrogen applied through fertilisers is absorbed by plants.

Nitrogen fertiliser comprises either urea, ammonium or nitrate and their mixtures. Urea nitrogen is not readily plant available and must undergo hydrolysis via the naturally occurring urease enzyme to ammonium (NH₄). Hydrolysis occurs when urea is applied to the soil surface leading to regular losses of 10-30% of ammonia to the atmosphere through ammonia volatilization.

Urease inhibitors (UIs)

To slow down the hydrolysis of urea, urease inhibitors (UIs) can be applied thereby reducing ammonia emissions by close to 70% (Bittman et al. 2014). As a result, less nitrogen is released into the environment and this nutrient remains available for growing crops. While ammonium nitrogen (NH₄⁺) is effectively retained by the soil and resistant to loss, naturally occurring soil bacteria convert it to nitrate (NO3-)  and release nitrous oxide ((N₂O) through nitrification. Nitrous oxide is a very potent greenhouse gas (2981x CO₂) with an atmospheric lifetime of over 100 years.

Nitrification inhibitors (NIs)

While ammonium nitrogen (NH₄⁺) is effectively retained by the soil and resistant to loss, naturally occurring soil bacteria convert it to nitrate (NO3-) and release nitrous oxide (N₂O) through nitrification. Nitrous oxide is a very potent greenhouse gas (2981x CO₂) with an atmospheric lifetime of over 100 years.
Nitrate can be reduced to nitrous oxide (N₂O) and nitrogen gas (N2) through denitrification.  In addition, nitrate is very mobile and can easily leach into ground and surface water, resulting in eutrophication – the formation of toxic algal blooms and the loss of biodiversity.  One of the solutions to minimize nitrogen losses is the use of nitrification inhibitors (NIs), which specifically inhibit the activity of microorganisms in the soil responsible for the conversion of ammonium to nitrate. Consequently, nitrous oxide emissions and nitrate leaching are reduced leading to ammonium being available to plants longer and in a form that best suits their needs.