Impact Factors of Fertilizers

Methods 5.0

Published

September 22, 2025

For FP v5, fertilizers have been enhanced with more reliable data and better options compared to FP v4.2. The impact factors for fertilizers in this section are associated with the energy use and GHG emissions from the manufacturing process, and these impacts are attributed to the Upstream boundary. The soil GHG emissions related to the use of nitrogen fertilizers, lime, and urea are accounted by methods from Ogle et al. (2024).

Details

Cradle-to-processing-gate emissions from fertilizer are primarily based on the Argonne National Laboratory (ANL) GREET Feedstock Carbon Intensity Calculator (FD-CIC) (Liu et al. 2023). This tool quantifies emissions from major fertilizer types, including ammonia, urea ammonium nitrate, urea ammonium nitrate, and others. The FD-CIC tool details the material and energy inputs required for fertilizer production, incorporating emissions from direct fuel combustion, chemical process emissions, and upstream material extraction and intermediary processing (Liu et al. 2023). To supplement the FD-CIC data for fertilizer types not included in the tool, additional emission factors are incorporated from other LCA databases (e.g. USLCI) and peer-reviewed literature (Gaidajis and Kakanis 2020; LEIF 2025; Fertilizers Europe 2024). Table 1 shows the primary sources of information for the various fertilizer options. CED for each material and energy input is based on National Renewable Energy Laboratory (2012) and LEIF (2025). The top eight fertilizers include both conventional and green production pathways, where ammonia is produced via electrolysis using hydrogen and nitrogen, resulting in fertilizers with lower carbon intensities compared to conventional production.

Table 1: Sources of impact factors for fertilizer options

Fertilizer	Primary Sources
Ammonia	Liu et al. (2023)
Urea	Liu et al. (2023)
Ammonium nitrate	Liu et al. (2023)
Ammonium sulfate	Liu et al. (2023)
Urea ammonium nitrate	Liu et al. (2023)
Calcium ammonium nitrate	Fertilizers Europe (2024); Liu et al. (2023)
Monoammonium phosphate	Liu et al. (2023)
Diammonium phosphate	Liu et al. (2023)
Potassium nitrate	Liu et al. (2023); LEIF (2025)
Sulfur	Liu et al. (2023); National Renewable Energy Laboratory (2012)
Lime	Liu et al. (2023)
Muriate of potash	Liu et al. (2023)
Boric acid	Liu et al. (2023); LEIF (2025); Gaidajis and Kakanis (2020)
Zinc sulfate	Liu et al. (2023); LEIF (2025); Gaidajis and Kakanis (2020)
Manganese oxide	Liu et al. (2023); LEIF (2025); National Renewable Energy Laboratory (2012)

The FD-CIC tool provides a breakdown of process emissions, representing the direct emissions associated with fuel combustion during production, as well as emissions released during chemical transformations. For instance, during the production of ammonia-based fertilizers, ammonia leakage contributes to indirect nitrous oxide emissions. The FD-CIC tool specifies total GHG emissions per unit of fertilizer production, differentiating between direct CO₂ emissions and total GHG emissions. The remaining GHG emissions (CH₄ and N₂O) are allocated based on the proportion of upstream emissions attributed to each gas type (Liu et al. 2023). We combine the material and energy input inventories for each of the fertilizer types with the cradle-to-gate emission factors included in the FD-CIC tool, including, for example, natural gas, diesel, nitric acid, and electricity.

The cumulative energy demand (CED) of fertilizer production is estimated by integrating energy input requirements for each production process with cradle-to-processing-gate CED factors (National Renewable Energy Laboratory 2012; LEIF 2025). This approach captures both the direct energy required for production and the embodied energy in raw material extraction, refining, and processing.

To provide representative fertilizer impact factors, weighted averages for nitrogen and phosphorus fertilizer are calculated using the U.S. average distribution of fertilizer use. Table 2 presents the percentage distribution of each fertilizer type, allowing for nationally representative GHG emissions and CED factors. In cases where emissions from less common nitrogen (N) and phosphorus (P2O5) fertilizers are aggregated, they are redistributed proportionally among the major fertilizer categories to maintain methodological consistency.

Table 2: Proportions of nitrogen and phosphorus fertilizers used in the U.S. (USDA 2019)

Fertilizer Type	Nitrogen	P₂O₅
Ammonia (anhydrous)	14%
Ammonia (aqueous)	1%
Ammonium nitrate	2%
Ammonium sulfate	7%
Urea ammonium nitrate	43%
Urea	25%
Other N	8%
Diammonium phosphate		35%
Monoammonium phosphate		38%
Other P		27%

Beyond macronutrient fertilizers, the assessment for FP v5 includes growth regulators and micronutrient fertilizers, which contribute to crop productivity but have unique production and emission characteristics. Growth regulator emissions, such as those associated with ethephon (ethylene dichloride), and micronutrient fertilizers, such as boric acid, zinc monosulfate, and manganese oxide (providing boron, zinc, and manganese nutrients) are based on the material and energy input inventories specified in the LCA databases found in National Renewable Energy Laboratory (2012) and Wang et al. (2023), with emissions from inputs based on GREET FD-CIC (Liu et al. 2023). For nitrogen, phosphorus, and potassium-based fertilizers, the emissions and CED per kg of product are divided by the nitrogen, P2O5, and K2O concentrations for each fertilizer type to estimate the impact per kg of nutrients (Table 3).

Table 3: Concentration of N, P2O5, and K2O per kg of fertilizer product.

Fertilizer	Concentration
Ammonia	82.4% N
Ammonia (aqueous)	20.6% N
Urea	46.7% N
Ammonium nitrate	35.0% N
Ammonium sulfate	21.2% N
Urea ammonium nitrate	32.0% N
Calcium ammonium nitrate	27.0% N
Monoammonium phosphate (MAP)	48% P₂O₅
Diammonium phosphate (DAP)	48% P₂O₅
Potassium nitrate	13% K₂O
Muriate of Potash	60% K₂O

Energy use

The energy use impact factors are described below.

System Boundary: The impact factors in this section are attributed to the Upstream boundary.
Source Category: It classifies the energy use to indicate it is associated with the production of fertilizers.
Source Detail: A given fertilizer option.
MJ: Impact factor of megajoules per unit.
Unit: Expected unit to use the MJ impact factor.

Table 4: Energy use associated with production of fertilizers, per unit of fertilizer applied.

System Boundary	Source Detail	MJ	Unit
Upstream	Ammonia (aqueous)	0.01	kg fertilizer
Upstream	Ammonia (aqueous) (green ammonia)	0.01	kg fertilizer
Upstream	Ammonia (conventional)	37.75	kg fertilizer
Upstream	Ammonia (green)	43.27	kg fertilizer
Upstream	Ammonium nitrate	14.70	kg fertilizer
Upstream	Ammonium nitrate (green ammonia)	15.87	kg fertilizer
Upstream	Ammonium sulfate	18.04	kg fertilizer
Upstream	Ammonium sulfate (green ammonia)	19.47	kg fertilizer
Upstream	Calcium ammonium nitrate	13.66	kg fertilizer
Upstream	Calcium ammonium nitrate (green ammonia)	14.48	kg fertilizer
Upstream	Diammonium phosphate	23.91	kg fertilizer
Upstream	Diammonium phosphate (green ammonia)	25.14	kg fertilizer
Upstream	Gypsum	0.00	kg fertilizer
Upstream	K2O	8.73	kg K2O
Upstream	Lime (calcitic)	0.03	kg fertilizer
Upstream	Lime (dolomitic)	0.03	kg fertilizer
Upstream	Micronutrient (boron)	12.15	kg fertilizer
Upstream	Micronutrient (manganese)	28.84	kg fertilizer
Upstream	Micronutrient (zinc)	32.32	kg fertilizer
Upstream	Monoammonium phosphate	22.41	kg fertilizer
Upstream	Monoammonium phosphate (green ammonia)	23.16	kg fertilizer
Upstream	Potash (MOP)	5.24	kg fertilizer
Upstream	Potassium nitrate	14.94	kg fertilizer
Upstream	Sulfur	6.64	kg fertilizer
Upstream	US average nitrogen fertilizer	55.42	kg N
Upstream	US average phosphate fertilizer	48.18	kg P2O5
Upstream	Urea	28.22	kg fertilizer
Upstream	Urea (green ammonia)	39.74	kg fertilizer
Upstream	Urea ammonium nitrate	53.58	kg fertilizer
Upstream	Urea ammonium nitrate (green ammonia)	67.82	kg fertilizer

GHG emissions

The GHG emission impact factors are described below.

System Boundary: The impact factors in this section are attributed to the Upstream boundary.
Source Category: It classifies the GHG emissions to indicate they are associated with the production of fertilizers.
Source Detail: A given fertilizer option.
CO2_fossil: Impact factor for fossil CO₂ in kg of gas per unit.
CH4_fossil: Impact factor of fossil CH₄ in kg of gas per unit.
N2O: Impact factor for N₂O in kg of gas per unit.
Unit: Expected unit to use the GHG emissions impact factor.

Table 5: GHG emissions associated with production of fertilizers.

System Boundary	Source Detail	CO2_fossil	CH4_fossil	N2O	Unit
Upstream	Ammonia (aqueous)	0.54	0.0015586	0.0000095	kg fertilizer
Upstream	Ammonia (aqueous) (green ammonia)	0.03	0.0000610	0.0000006	kg fertilizer
Upstream	Ammonia (conventional)	2.16	0.0062343	0.0000381	kg fertilizer
Upstream	Ammonia (green)	0.05	0.0001044	0.0000010	kg fertilizer
Upstream	Ammonium nitrate	0.24	0.0061190	0.0037640	kg fertilizer
Upstream	Ammonium nitrate (green ammonia)	0.20	0.0048329	0.0037565	kg fertilizer
Upstream	Ammonium sulfate	0.14	0.0016980	0.0000109	kg fertilizer
Upstream	Ammonium sulfate (green ammonia)	0.10	0.0001405	0.0000019	kg fertilizer
Upstream	Calcium ammonium nitrate	0.45	0.0022787	0.0000544	kg fertilizer
Upstream	Calcium ammonium nitrate (green ammonia)	0.14	0.0013677	0.0000489	kg fertilizer
Upstream	Diammonium phosphate	0.84	0.0029129	0.0000262	kg fertilizer
Upstream	Diammonium phosphate (green ammonia)	0.80	0.0015764	0.0000185	kg fertilizer
Upstream	Gypsum	0.03	0.0000462	0.0000002	kg fertilizer
Upstream	K2O	0.45	0.0009157	0.0000068	kg K2O
Upstream	Lime (calcitic)	0.01	0.0000114	0.0000000	kg fertilizer
Upstream	Lime (dolomitic)	0.01	0.0000114	0.0000000	kg fertilizer
Upstream	Micronutrient (boron)	0.47	0.0009837	0.0001148	kg fertilizer
Upstream	Micronutrient (manganese)	1.78	0.0029312	0.0002378	kg fertilizer
Upstream	Micronutrient (zinc)	1.59	0.0041184	0.0002050	kg fertilizer
Upstream	Monoammonium phosphate	0.89	0.0026207	0.0000257	kg fertilizer
Upstream	Monoammonium phosphate (green ammonia)	0.87	0.0018060	0.0000211	kg fertilizer
Upstream	Potash (MOP)	0.27	0.0005494	0.0000041	kg fertilizer
Upstream	Potassium nitrate	0.42	0.0014692	0.0106350	kg fertilizer
Upstream	Sulfur	0.33	0.0010044	0.0000071	kg fertilizer
Upstream	US average nitrogen fertilizer	0.76	0.0111846	0.0026369	kg N
Upstream	US average phosphate fertilizer	1.80	0.0057498	0.0000540	kg P2O5
Upstream	Urea	-0.21	0.0046282	0.0000293	kg fertilizer
Upstream	Urea (green ammonia)	-0.30	0.0012093	0.0000087	kg fertilizer
Upstream	Urea ammonium nitrate	0.68	0.0138985	0.0054250	kg fertilizer
Upstream	Urea ammonium nitrate (green ammonia)	0.53	0.0083196	0.0053933	kg fertilizer

Additional support

Field to Market has received requests over the years for a way to work with these impact factors outside the Fieldprint Platform — to compare fertilizer options, or to see how the choice of Global Warming Potential (GWP) values changes a result. The Fertilizer Impact Factors Calculator is an Excel workbook that does this. It applies IPCC GWP factors to the emission factors published above and reports a single kg CO₂e figure per unit of fertilizer, at whatever application rate you enter.

Download spreadsheet

Set three cells on the Settings tab — the IPCC Assessment Report, the time horizon, and an application rate — and read the results on the Impact Factors tab. Full instructions and a worked example are in the calculator user guide, which is also downloadable as a markdown file.

Two things to check before relying on a result:

Read the units. Most rows are per kg of fertilizer product. Three rows — K₂O, US average nitrogen fertilizer, and US average phosphate fertilizer — are per kg of nutrient. Entering an application rate against the wrong kind of row produces an answer that is wrong by a factor of two or more.
Urea’s negative CO₂ value is expected. Manufacturing urea captures CO₂ into the urea molecule, so the production-stage carbon balance is negative. That CO₂ is released after application to soil, which falls outside this workbook’s cradle-to-processing-gate boundary and is accounted for separately by CO₂ from urea fertilizer.

← Return to list of impact factor categories

References

Fertilizers Europe. 2024. Carbon Footprinting in Fertilizer Production. https://www.fertilizerseurope.com/initiatives/carbon-footprint-calculator/.

Gaidajis, Georgios, and Ilias Kakanis. 2020. “Life Cycle Assessment of Nitrate and Compound Fertilizers Productiona Case Study.” Sustainability 13 (1): 148.

LEIF. 2025. Impact Factors. https://www.leifllc.com/.

Liu, Xinyu, Hao Cai, Hoyoung Kwon, and Michael Wang. 2023. Feedstock Carbon Intensity Calculator (FD-CIC): Users’ Manual and Technical Documentation.

National Renewable Energy Laboratory. 2012. U.s. Life Cycle Inventory Database. https://www.nrel.gov/analysis/lci.

Ogle, Stephen M, Paul R Adler, Gary Bentrup, et al. 2024. “Chapter 3: Quantifying Greenhouse Gas Sources and Sinks in Cropland and Grazing Land Systems.” In: Hanson, Wes L.; Itle, Cortney; Edquist, Kara, Eds. Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory. Technical Bulletin Number 1939, 2nd Edition. Washington, DC: US Department of Agriculture, Office of the Chief Economist. 6-1-6-23. Chapter 3. 1939: 31.

USDA. 2019. “Fertilizer Use and Price.” US Department of Agriculture, Economic Research Service.

Wang, Michael, Amgad Elgowainy, Uisung Lee, et al. 2023. Summary of Expansions and Updates in r&d GREET® 2023. Argonne National Laboratory (ANL), Argonne, IL (United States).