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 (MOP) 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

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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, Justin Derner, Grant Domke, Stephen Del Grosso, Johannes Lehmann, Michele Reba, and Dominic Woolf. 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, Kwang Hoon Baek, Sweta Balchandani, Pahola Thathiana Benavides, Andrew Burnham, et al. 2023. “Summary of Expansions and Updates in r&d GREET 2023.” Argonne National Laboratory (ANL), Argonne, IL (United States).