Dr Claudia Luiza Manfredi Gasparovic, a renowned researcher in Industrial Ecology at Nium, delves into the complexities of ammonia production and underscores the significant role of field emissions in the fertiliser supply chain's greenhouse gas output.
This article presents promising strategies for optimising nutrient management and adopting conservation tillage practices to address field emissions. When combined with clean ammonia deployment, these strategies can significantly amplify climate change mitigation efforts.
In a case study, Claudia also estimates emissions reductions by 2030 to illustrate the potential impact of these strategies. Integrating clean ammonia with mitigation measures could surpass emissions reduction targets, underscoring the crucial role of systemic approaches and partnerships in our collective journey towards broader sustainability goals.

Current ammonia production is the most polluting chemical industrial process in the world in terms of CO2 emissions: 450MtCO2 per year, 315MtCO2 of which is for fertiliser (Menegat et al., 2022). Decarbonising ammonia production is an Archimedes lever for climate mitigation.
However, direct process emissions are only about 40% of total greenhouse gas (GHG) emissions in the fertiliser supply chain (Menegat et al., 2022). There is also transport, production and use of derivatives like urea and, critically, field emissions.
In general, the current incentive structure in agriculture means we are applying more nitrogen to the soil than plants can absorb. About half of the nitrogen is lost to air, water, and soil, unbalancing the natural cycles and harming ecosystems and biodiversity.
Moreover, bacteria break down some nitrogen lost in the soil, producing nitrous oxide (N2O), a greenhouse gas 298 times more potent than carbon dioxide in causing climate change (Zhu-Barker et al., 2019).
N2O emissions from synthetic fertiliser use account for 56.6% of GHG emissions in the ammonia supply chain (about 662mi tCO2eq) and 0.75% of total anthropogenic GHG emissions (IPCC, 2023).
The challenge of reducing N2O emissions
So, how do we tackle these emissions? Several strategies are available:
- Reducing the amount of fertiliser used in agriculture by better matching it to plant needs.
- Reducing the amount of nutrients lost to the environment.
- Reducing the amount of nitrogen lost that gets turned into N2O.
The former two options are preferable because they tackle other environmental issues associated with fertiliser loss.
Strategies include formulations with microbial inhibitors or slow-release fertilisers (which account for less than 5% of the market), conservation tillage, control-release fertilisers, deep placement or smaller, split applications during the growing season (Cassman & Dobermann, 2022) (Yadav et al., 2017), and choosing the right fertiliser for each situation.
Strategies such as these and more comprehensive changes in the agri-food system could reduce fertiliser emissions by 70% (IFA 2022). If implemented with clean ammonia deployment, they could amplify the technology's impact on mitigating climate change.
Reducing N2O emissions: a case study
To illustrate the potential of N2O mitigation strategies, we use literature data and modelling to estimate how much N2O is produced from a certain amount of clean ammonia for fertiliser and how much it could be reduced by implementing a combination of mitigation approaches in 2030.
The table below presents the expected N2O emissions for 4.2Mt ammonia (3% of market share according to IEA scenarios).
Clean ammonia produced | 4.2 Mt |
Emission factor (kgN2O/kgNH3) | 1.25% |
N2O emissions | 0.0525 MtN2O |
Equivalent emissions | 15.645 MtCO2eq |
Impact of mitigation strategies
A few mitigation strategies were selected, and data from their emissions reduction potential was compiled by literature, as presented:
- Nutrient expert management—20-54.8%. This is a fertilisation decision system aimed at optimising nutrient inputs considering demand (plant needs). Moreover, nutrients are supplied according to time and space variation, ensuring field-specific nutrient management in a particular cropping season.
- Nitrification inhibitors—40%. Fertilisers with formulations that include inhibitors of microbial activity to prevent bacteria from turning nitrogen into N2O.
- No-till practices—30%. Agricultural practices for growing crops without disturbing the soil through tillages.
- Reduced tillage and fertiliser application through drop irrigation—72%. An association of the mentioned practices.
- Biochar-based N fertiliser—65% (efficiency). Products are made by physically mixing biochar and N fertiliser or coating chemical N fertilisers, such as prilled urea, with biochar.
Two Scenarios for deployment
We consider a mix of these strategies in two scenarios in which they are implemented alongside applying fertiliser corresponding to 50% and 90% of the 4.2Mt of ammonia. This considers that the type of fertiliser applied is whichever was used in the studies referenced. The tables (below) show the deployment share considered for each strategy and the total emissions reduction potential.
Scenario 1: mitigation in 50% of deployment
Mitigation strategies | Emissions reductions | Share in deployment | Emissions red total |
None | 0.00% | 50% | 0% |
Nutrient expert | 20% | 10% | 2.00% |
Nutrient expert | 54.80% | 10% | 5.48% |
No-Till | 30.00% | 10% | 3.00% |
Nitrification inhibitors | 40.00% | 10% | 4.00% |
Reduced tillage +drop irrigation | 72.00% | 5% | 3.60% |
Biochar-based | 65.00% | 5% | 3.25% |
Total | — | 100% | 21% |
Scenario 2: mitigation in 90% of deployment
Mitigation strategies | Emissions reductions | Share in deployment | Emissions red total |
None | 0.00% | 10% | 0% |
Nutrient expert | 20% | 9% | 1.80% |
Nutrient expert | 54.80% | 18% | 9.86% |
No Till | 30.00% | 18% | 7.20% |
Nitrification inhibitors | 40.00% | 18% | 12.96% |
Reduced tillage +drop irrigation | 72.00% | 18% | 3.60% |
Biochar-based | 65.00% | 9% | 5.85% |
Total | — | 100% | 43.07% |
Translated into the N2O emissions avoided, the emissions reduction potential for the scenarios with 50% and 90% deployment, respectively, are 3.34 and 6.75MtCO2 eq.
Impact on 2030 goal of 10MtCO2
How do these reductions compare to the ones achieved by replacing fossil fuel ammonia production with clean ammonia produced with the minion reactors? And how are they situated with respect to Nium's goal of achieving 10MtCO2 reductions in 2030?
To answer this, we added the emissions reductions for these two mitigation case studies with the emissions reductions for replacing dirty ammonia with clean ammonia for different technologies (more details on the assumptions and methods for these estimates can be found in another article in Nium's website: Eliminating fertiliser production emissions: the path to 10MtCO2 by 2030. They consider two IEA scenarios for the ammonia market in 2030 (IEA, 2021): a conservative one, Stated Policies (the current trajectory) and a more optimistic one, Sustainable Development (which assumes more changes in technologies, fuel and behaviour, therefore reducing baseline emissions).
The results are presented in the graphs below.


Conclusions
Associating deployment of Nium's tech/product with N2O mitigation measures can:
- Potentialise the emissions reduction potential of each ton of Nium's ammonia (up to 400% increase with 90% deployment, or 182% increase with 50% deployment)
- Help Nium reach its BHAG with less ammonia on the market (in the Stated Policies scenario, with 90% of deployment of mitigation strategies, even the lowest technology potential for emissions reductions reaches the 10MtCO2eq goal)
- Accelerate GHG mitigation while providing environmental co-benefits, aligning deployment with EU / FAO policies and broader sustainability metrics.
Actual mitigation potential needs to be studied on a case basis as mitigation strategies' performance depends on soil, climate, and other factors.
By applying a systemic view, innovative partnerships, and strategies, we can maximise the emissions reduction potential of Nium's clean ammonia while providing environmental co-benefits and helping pave the path to a better planet for future generations.
Dr Claudia Luiza Manfredi Gasparovic | Published: 12/02/2024
References
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IFA. 2022. "Reducing Emissions from Fertilizer Use Report." International Fertilizer Association. Link: https://www.fertilizer.org/key...
Greenhouse Gas Emissions from Global Production and Use of Nitrogen Synthetic Fertilisers in Agriculture. Link: https://www.nature.com/article...
Nitrous Oxide (N2O): The Dominant Ozone-Depleting Substance Emitted in the 21st Century. Link: https://www.science.org/doi/10...
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Soil Management Practices to Mitigate Nitrous Oxide Emissions and Inform Emission Factors in Arid Irrigated Specialty Crop Systems. Link: https://www.mdpi.com/2571-8789...