Nitrogen stabilizers are great, but are they right for you?

This guide outlines how to test the feasibility of nitrogen stabilizers when you want to reduce the footprint of your agricultural practices or products and be able to reduce Scope 3 emissions. 

To support this we are releasing a greenhouse gas (GHG) methodology to help quantify and certify the emission reductions that happen when you adopt nitrogen stabilizers.

In this blog we will cover everything you need to know to conduct a feasibility study before you start implementing an actual project. Typical topics are:

• Science behind nitrogen stabilizers
• Business case
• Applicability & eligibility
• Additionality
• Baseline
• Crediting period
• Spatial and temporal boundaries, and MRV
• GHG quantification

What are nitrogen stabilizers?

Nitrogen stabilizers, usually urease inhibitors (UI) and nitrification inhibitors (NI), are fertilizers additives that help reduce nitrogen loss. Urease inhibitors slow down the conversion of urea into ammonia, decreasing ammonia volatilization and keeping nitrogen available longer for plant uptake. Nitrification inhibitors delay the conversion of ammonium into nitrate, reducing nitrate leaching and lowering nitrous oxide (N₂O) emissions. 

Beyond reducing N₂O emissions, nitrogen stabilizers also improve nitrogen use efficiency (NUE), making more nitrogen available to crops for longer. This can lead to higher yields from the same amount of fertilizer, better soil health, and less nitrate leaching into water, which improves water quality. These benefits support sustainable farming by boosting productivity while protecting the environment.

Who is going to pay?

As part of the feasibility study you will also determine the business case of the sustainability project. Nitrogen stabilizers typically add an extra cost to the farming practice and you should not expect one player to pay for it all. For instance, you can not expect farmers to adopt nitrogen stabilizers AND pay for them. The cost needs to be shared across the supply chain, where downstream partners like food manufacturers, commodity traders, and retailers can co-finance the project through insetting. When the emission reductions are quantified and verified, the resulting emission reduction certificates can be used to claim and report a Scope 3 footprint reduction by supply chain participants.

Applicability and eligibility

You can’t jump into a sustainability project without being certain (and with proof) that the intervention you’re integrating in your farmer practices is actually effective. 

First of all: 

• You must apply nitrogen stabilizers (urease inhibitors (UI), nitrification inhibitors (NI), or a combination of both) into your fertilization practices.
• You are applying inorganic or organic fertilizers (urea, ammonium nitrate, DAP, etc.) where these stabilizers can make a measurable difference.
• You must be using nitrogen stabilizers and fertilizer products that are registered and legally approved in the country where you apply them (e.g., EU PFC5, US FIFRA/AAPFCO)

Real-world examples of interventions are:

• A farmer switches from regular urea to NBPT-treated urea (a UI) for their maize field.
• A farmer cooperative distributes DMPP-treated ammonium nitrate (a NI) across several thousand hectares.
• A coffee plantation uses UI+NI blends in fertigation systems for high-value crops.

Additionality

For a GHG project, you must prove some form of additionality, meaning that the adoption of nitrogen stabilizers would not have happened without the project.

For projects within the supply chain (insetting), you must prove:

• The use of stabilizers is not required by regulation.
• Whether the use of stabilizers is already common in your sourcing region.
• The project is helping farmers adopt the practice earlier or more widely.

For projects outside the supply chain (offsetting), you must prove three things:

• Regulatory additionality: No laws forcing the practice. 
• Prevalence: It is not common practice in the region.
• Financial: The use of nitrogen stabilizer would not have occurred without carbon finance.

Baseline

You will also determine the baseline emissions for the project. This is a figure that represents the fertilizer-related emissions without stabilizers. The baseline can be set at the field level, based on individual plots you monitor, or at the regional level, based on typical fertilizer use in the area. 

Crediting period

A project can issue emission reduction certificates for up to 7 years, after which the project design is re-evaluated. Keep in mind that certificates can only be issued for years when nitrogen stabilizers are actually used. You can apply for up to 2 years of retroactive crediting.

Spatial and temporal boundaries, and MRV

For a nitrogen stabilizer project, or any GHG project, you must define spatial and temporal boundaries and adhere to monitoring, reporting, and verification (MRV) requirements.

Spatial boundaries define the project area. You can design the project at:

• Field level: you track emissions from individual fields.
• Sourcing-region level: if you can’t track individual fields, you can base quantification on how much stabilized fertilizer is used across the region. 

Temporal boundaries define when monitoring starts and ends.

• Field level: monitoring typically runs from first fertilizer application to harvest.
• Sourcing-region level: a 12-month monitoring period. 

MRV requirements are designed to be practical while delivering reliable data. Each season, you must document field and crop data, fertilizer and stabilizer use, and other relevant parameters. The reporting frequency follows the temporal boundary you set. A qualified validation and verification body (VVB) will review your data and calculations to confirm compliance and integrity.

GHG emission quantification

The GHG methodology helps quantify and certify the emission reductions that happen when you adopt nitrogen stabilizers only covers emissions affected by nitrogen fertilizer application and the use of nitrogen stabilizers. This includes:

• Direct N₂O emissions: From soil after nitrogen is applied.
• Indirect N₂O emissions: From nitrogen loss as ammonia or nitrate, later converted to N₂O.
• Cradle-to-gate emissions of fertilizers: Manufacturing and transport emissions.
• Cradle-to-gate emissions of stabilizers: Production and delivery of stabilizers .

Most projects involve adopting stabilizers without changing nitrogen rates. This keeps yields stable, allows for a clean comparison between baseline and project, and makes it easier to measure real emission reductions.

Emissions are calculated using standard equations and emission factors that are retrieved from high quality field experiments and scientific studies.

Now what?

So, given all of the above, what are your next steps?

• Run a feasibility study to check items above.
• The outcome of the study should give you enough confidence to start an actual GHG project as the expected impact has become much more clear to you.
• In a blog we published earlier we shared a step-by-step process to starting a GHG project with Proba. 
• If you need any help or guidance, don’t hesitate to reach out to us.