How much nitrogen does rice straw left in the field add for nitrous oxide under the Intergovernmental Panel on Climate Change Tier 1 method?

Tier 1 takes above-ground rice residue as yield dry matter in tonnes times 0.95, plus 2.46 tonnes per hectare, then the residue in kilograms (kg) times 0.007 for nitrogen. At 4 tonnes of fresh paddy per hectare that is about 41 kg of nitrogen above ground, or 0.12 kg of nitrous oxide nitrogen on flooded rice at 0.003.

The steps for rice

1. Convert the harvested yield to dry matter with the dry matter fraction for rice, 0.89 (Table 11.2 and Equation 11.7).
2. Above-ground residue in tonnes per hectare = yield dry matter in tonnes per hectare x slope 0.95 + intercept 2.46.
3. Nitrogen in above-ground residue = that residue in kilograms x 0.007 (the table's nitrogen content for rice).
4. Subtract residue that is removed, for example for feed, bedding or construction. The guide says to assume no removal if you have no data.
5. Where the straw is burnt on the field, the burnt part, area burnt times the combustion factor, is taken out of the area that returns residue (Equation 11.6).
6. Multiply the returned nitrogen by the factor for nitrogen inputs: 0.003 kg of nitrous oxide nitrogen (N2O-N) per kg of nitrogen on flooded rice fields, or 0.01 elsewhere (Table 11.1), then by 44/28 to get nitrous oxide (N2O).

What the table does not give for rice

Table 11.2 gives rice a below-ground biomass ratio of 0.16 but prints NA (not available) for the nitrogen content of below-ground residues. So the table alone completes only the above-ground term for rice. The guide says Tier 2 would use country-specific values instead; for roots, say what value you took and where it came from.

Where the number sits

• Residue nitrogen is one of the inputs in Equation 11.1 alongside fertiliser and manure, all sharing the same factor.
• It is also an input to the leaching term where leaching applies.
• For a farm you run, it is part of the farm's own emissions. For rice you buy, it is part of the emissions in the purchased crop.

1 hectare, 4,000 kg fresh paddy, nothing removed, nothing burnt, flooded

• Dry matter: 4,000 x 0.89 = 3,560 kg, which is 3.56 tonnes
• Above-ground residue: 3.56 x 0.95 + 2.46 = 5.84 tonnes
• Nitrogen: 5,842 x 0.007 = 40.9 kg
• Direct N2O-N on flooded rice: 40.9 x 0.003 = 0.123 kg; x 44/28 = 0.193 kg N2O; x 273 = about 52.6 kg carbon dioxide equivalent (CO2e)
• The same nitrogen on a field not flooded, at 0.01: 40.9 x 0.01 x 44/28 x 273 = about 175 kg CO2e

Yield is an example value. 273 is the Sixth Assessment Report (AR6) 100-year warming potential for N2O. Roots are left out because the table has no rice figure for them. Fertiliser nitrogen is added separately.

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.

• Fertiliser nitrous oxide calculation
• Burning paddy straw: emissions per acre
• Rice straw ploughed in early or late

Sources: IPCC 2006 Guidelines, Volume 4, Chapter 11, Equations 11.1, 11.6, 11.7 and 11.7A, Tables 11.1 and 11.2, IPCC Sixth Assessment Report, Working Group I, Chapter 7, Table 7.15 (100-year global warming potential: methane of non-fossil origin 27.0, nitrous oxide 273)

Last reviewed 2026-11-05. Values are from the 2006 edition. The guide expects Tier 2 country values to replace them where available.