Reducing emissions with nitrification inhibitors

Using nitrification inhibitors (NI) alongside fertiliser application can reduce leaching and emissions of nitrous oxide (N₂O), a long-lived gas with high global-warming potential.

NIs can be added to nitrogen-based liquid fertilisers before application or sprayed onto soil before spreading solid fertilisers. They can also be used with livestock manures and other organic materials that are spread onto land or applied directly to soil.

When ammonium is converted to nitrate in the soil the process is known as nitrification. This nitrate can then be converted N₂O and gets emitted into the atmosphere.

NIs work by inhibiting the biological conversion of ammonium to nitrate, retaining fertiliser N in the less-mobile ammonium form. This reduces the release of N₂O gas into the atmosphere. It can also reduce N losses from nitrate leaching, helping protect water quality.

One study on UK soils showed:

• 58% reduction in N₂O emissions from grassland soils
• 81% reduction in N₂O emissions from arable soils

In practice, how effective they are depends on the type of fertiliser used and the soil conditions it is applied to.

NIs don’t inherently increase yields for growers, so at this time it would be an extra cost to implement.

Advice on product choice should be sought from a FACTS-qualified adviser.

• Choose the correct NI for the crop. For example:
  • Dicyandiamide (DCD) is suitable for vegetables
  • Dimethylpyrazole phosphate (DMPP) is more suited to maize
• Plan the application of a NI. For complete agronomic advice on product choice and guidelines for use, consult a FACTS-qualified adviser
• Apply with fertiliser or directly to soil
• If using a urea-based product, NIs can be used in combination with urease inhibitors (aka protected urea)

The use of plasma (ionised gas) technology is a single-step, environmentally friendly alternative to the Haber-Bosch process.

This project aims to demonstrate the feasibility of a plasma-based mobile fertiliser machine that produces fertiliser using only air, water and electricity.