Key terms used throughout the dashboard
Biological nitrogen fixation (BNF) is the term used for a process in which nitrogen gas (N₂) from the atmosphere is incorporated into the tissue of certain plants. Only a select group of plants is able to obtain N this way, with the help of soil microorganisms. Among forage plants, the group of plants known as legumes (plants in the botanical family Fabaceae) are well known for being able to obtain N from air N₂.
Source: OSU, https://forages.oregonstate.edu/nfgc/eo/onlineforagecurriculum/instructormaterials/availabletopics/nitrogenfixation/definition
Carbon dioxide equivalent (CO2e) emission represents the amount of carbon dioxide (CO2) emission that would cause the same integrated radiative forcing or temperature change, over a given time horizon, as an emitted amount of a greenhouse gas (GHG) or a mixture of GHGs. There are a number of ways to compute such equivalent emissions and choose appropriate time horizons. Most typically, the CO2-equivalent emission is obtained by multiplying the emission of a GHG by its global warming potential (GWP) for a 100-year time horizon. On this dashboard, "Mt CO₂e" means megatonnes of CO₂-equivalent — the mass units above (t/kt/Mt/Gt) apply the same way to CO₂e quantities.
Source: IPCC
Crop residue is defined as the vegetative crop material left on a field after a crop is harvested, pruned or processed. Farmers are encouraged as much as possible to work crop residues back into the soil or to compost them for use as a soil amendment. Recycling crop residues helps control pests, prevent erosion and preserve or improve soil quality.
Source: Government of British Columbia, https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/agricultural-land-and-environment/strengthening-farming/farm-practices/870218-30_crop_residue_management.pdf
A cropland nitrogen (N) balance measures the difference between total nitrogen inputs (such as synthetic fertilizers, manure, atmospheric deposition, and biological fixation) and outputs (such as crop harvest removal).
Source: FAOSTAT
Nitrogen (typically as nitrate, NO₃⁻) that has migrated below the actively cycling root zone into deeper, unsaturated soil layers (the vadose zone), where it accumulates or moves slowly toward groundwater. Because transit through deep soil layers can take years to decades, this "legacy" nitrogen store delays — but does not eliminate — the leaching signal from surface N inputs reaching groundwater or surface water. This affects how researchers interpret time lags between fertilizer/management changes and observed water-quality outcomes.
Source: Weitzman JN, Brooks JR, Compton JE, Faulkner BR, Mayer PM, Peachey RE, Rugh WD, Coulombe RA, Hatteberg B, Hutchins SR. Deep soil nitrogen storage slows nitrate leaching through the vadose zone. Agric Ecosyst Environ. 2022 Jul 1;332:1-13. doi: 10.1016/j.agee.2022.107949. PMID: 35400773; PMCID: PMC8988158.
Under the U.S. Safe Drinking Water Act, EPA sets two related benchmarks for nitrate in drinking water: Maximum Contaminant Level (MCL): 10 mg/L as nitrogen (equivalent to ~44–45 mg/L measured as the nitrate ion, NO₃⁻) — the legally enforceable limit for public water systems, set equal to the MCLG because it is feasible to measure and treat to that level. For nitrite, the MCL/MCLG is 1 mg/L (as nitrogen).
Source: EPA
Direct emissions of greenhouse gases are from sources that are owned or controlled by the reporting organization, while indirect emissions result from the activities of the reporting organization but are generated at sources owned or controlled by another organization. In the context of this metric, indirect emissions refer to GHG emissions from the generation of electricity, heat, or steam that is imported and consumed by the reporting organization.
Source: GHG Protocol, https://ghgprotocol.org/calculation-tools-faq
Nitrous oxide (N₂O) emitted directly from the soil at the site where nitrogen (N) is added via microbial nitrification and denitrification of that N. N₂O emitted away from the site of the original N application, after that nitrogen has left the field via volatilization or leaching, is indirect.
Source: FAOSTAT
The loss of soluble nutrients such as nitrate, as it is washed through the soil profile by the drainage of rain or irrigation water.
Source: FAOSTAT
Land use, land use change and forestry (LULUCF) measures net carbon removals from the land use, land use change and forestry sector, considering both emissions and removals from the sector. The indicator is expressed as CO2 equivalents using the global warming potential (GWP) of each gas.
Source: Eurostat
Waste materials produced by domestic livestock (vegetative material such as green manures are considered to be crop residues or compost). The term "manure" is used here collectively to include both dung and urine (i.e., the solids and the liquids) produced by livestock.
Source: IPCC
Nitrogen (N) deposition describes the input of reactive nitrogen from the atmosphere to the biosphere both as gases, dry deposition and in precipitation as wet deposition. Enhanced reactive nitrogen deposition is a consequence of global emissions of oxidised nitrogen (NO, HNO3 and NO2 — often referred to as NOy) from fossil fuel combustion, and reduced N (NHx) from agricultural sources.
Source: UK Air Pollution Information System (APIS), https://www.apis.ac.uk/overview/pollutants/nitrogen_deposition
Nitrogen use efficiency (NUE) is the ratio of N recovered in the final output to the total N used as input. Increasing NUE aims to recover as much as possible of the N input as possible in the final product, thereby minimizing the amount of N lost in the production process.
Source: FAO. 2025. Sustainable nitrogen management in agrifood systems. Rome. https://doi.org/10.4060/cd3388en
Refers to the sector that generates, transmits, and distributes electricity to homes, businesses, and public infrastructure. Energy sources range from emissions-intensive (e.g., coal) to zero-emitting (e.g., nuclear, solar, wind, and hydro). The use of coal and natural gas to produce electricity is the key driver of the power sector's overall pollution emission levels, such as NOx emissions.
Source: EPA, https://www.epa.gov/power-sector/basic-information-site-map
Volatilisation of chemicals from soil is the transfer of the chemical as a gas through the soil-air interface under environmental conditions; volatilization from plants is the corresponding process. Its ecotoxicological importance is due, on the one hand, to the fact that it is the main pathway of exposure reduction of the soil ecosystem to not-readily biodegradable chemicals.
Source: Irene Scheunert, Ecotoxicological Testing, in Handbook of Hazardous Materials, Academic Press, 1993, pp. 223-232, ISBN 9780121894108, https://doi.org/10.1016/B978-0-12-189410-8.50024-9
To keep numbers readable, the dashboard automatically picks whichever unit in a measure’s family (see the mass, monetary, and count entries below) keeps the displayed value in a sensible range — a very small country’s emissions might show in kt or t instead of Mt, and a very large country’s in Gt. This only affects on-screen display: downloaded files (CSV/XLSX) always keep the original unit the dataset was published in, so the underlying numbers are never changed, only how large a country’s figures are re-expressed for readability. See the unit equivalence tables below for exact conversions.
Metric mass units used for emissions and fertilizer/nutrient quantities, each 1,000× the one before it: tonne (t) → kilotonne (kt) → megatonne (Mt) → gigatonne (Gt). See the equivalence table below for exact conversions.
Abbreviated US dollar amounts (used for GDP and similar economic indicators), each 1,000× the one before it: dollars ($) → thousands (k$) → millions (M$) → billions (B$) → trillions (T$). See the equivalence table below for exact conversions.
Abbreviated plain counts (used for population and similar figures), each 1,000× the one before it: thousands (k) → millions (M) → billions (B). See the equivalence table below for exact conversions.
| N | nitrogen |
| N₂ | dinitrogen |
| NH₃ | ammonia |
| NH₄⁺ | ammonium |
| N₂O | nitrous oxide |
| NO₂⁻ | nitrite |
| NO₃⁻ | nitrate |
| NOx | nitrogen oxides |
| O₃ | ozone |
Exact conversions for the abbreviated units described above — the same values the dashboard's automatic unit-switching uses.
| 1 t (tonne) | 1,000 kg |
| 1 kt (kilotonne) | 1,000 t |
| 1 Mt (megatonne) | 1,000 kt = 1,000,000 t |
| 1 Gt (gigatonne) | 1,000 Mt = 1,000,000,000 t |
| $1 | 1 US dollar |
| 1 k$ | 1,000 $ |
| 1 M$ | 1,000 k$ = 1,000,000 $ |
| 1 B$ | 1,000 M$ = 1,000,000,000 $ |
| 1 T$ | 1,000 B$ = 1,000,000,000,000 $ |
| 1 k | 1,000 |
| 1 M | 1,000 k = 1,000,000 |
| 1 B | 1,000 M = 1,000,000,000 |