A farm applies urea mixed with other nitrogen fertilisers in a solution. How much of it counts for the Intergovernmental Panel on Climate Change urea carbon dioxide step?

Count the urea share of the solution at 0.20 tonnes of carbon per tonne of urea, times 44/12. The Intergovernmental Panel on Climate Change (IPCC) says that if the share is not known, good practice is to assume the whole solution is urea, rather than under-estimate.

What the guide says

• Equation 11.13 of the IPCC 2006 Guidelines, Volume 4: carbon dioxide carbon (CO2-C) from urea = tonnes of urea applied x 0.20. The factor equals the carbon content of urea, 20% for CO(NH2)2.
• Multiply by 44/12 to convert carbon to carbon dioxide (CO2).
• Urea is often applied in combination with other nitrogenous fertilisers, particularly in solutions, so the urea proportion has to be estimated for the amount of urea.
• If the proportion is not known, the guide says it is good practice to assume the entire solution is urea, rather than potentially under-estimating emissions.

What to ask the seller

Ask for the urea content on the label, the delivery note or the product data sheet, as a share of the product weight. With that, the full-solution assumption is not needed. Keep the document with the purchase record, because it is the evidence for the share you used.

What this step leaves out

• The factor applies to urea carbon only. Nitrogen in other forms in the blend does not carry this carbon, though its nitrogen still counts in the nitrous oxide steps.
• The default carries an uncertainty of minus 50%, and the guide notes it cannot exceed the factor, because the factor is the absolute maximum.
• The guide says soil inorganic carbon gains from urea are not a net removal; the removal is estimated in the Industrial Processes and Product Use sector, Volume 3.

10 tonnes of solution applied

• Label says 40% urea (example share): 10 x 0.40 = 4 tonnes of urea; 4 x 0.20 x 44/12 = 2.93 tonnes CO2
• Share not known: assume 10 tonnes of urea; 10 x 0.20 x 44/12 = 7.33 tonnes CO2
• Difference from the label: 7.33 minus 2.93 = 4.40 tonnes CO2 that a label share takes out of the estimate

The 40% share is an example value, not a typical product. Nitrous oxide from the nitrogen in the solution is calculated separately from the nitrogen content.

What Senseible does here

Senseible reads fuel invoices and electricity bills into emission records, so diesel for tractors and power for irrigation pumps show up once uploaded. The fertiliser, residue and field figures on this page come from your own farm records.

• Emissions from applying a tonne of urea
• Emission factor for purchased urea and DAP
• Fertiliser nitrous oxide calculation

Sources: IPCC 2006 Guidelines, Volume 4, Chapter 11, Section 11.4 and Equation 11.13

Last reviewed 2026-11-05. Rule is from the 2006 edition. Replace the full-solution assumption with the label share once you hold it.