# How do rice AWD carbon credits account for nitrous oxide from fertiliser?

Canonical: https://senseible.earth/answers/rice-awd-credits-nitrous-oxide-farm-logbook

VM0051 v1.1 makes farmers record all nitrogen inputs in farm logbooks. If fertiliser use rises, default IPCC-based calculations add the extra nitrous oxide. If a farm only switches to wetting and drying, a separate correction factor covers the small rise from dry spells. ICVCM calls the approach practical and conservative.

## Why nitrous oxide matters

Methane falls when a paddy is drained between floods, because less organic matter breaks down without oxygen. Dry spells let air back into the soil, which can raise nitrous oxide. A credit that ignores this would overstate the gain.

## What the methodology requires

- All nitrogen inputs go into farm logbooks, which makes fertiliser use visible.
- Where nitrogen inputs increase, default calculation methods estimate the added nitrous oxide.
- Where a project moves to wetting and drying without changing nitrogen inputs, a correction factor accounts for the partial increase. ICVCM expects this to be the most common case.

## Where the numbers come from

The default values are based on the IPCC Guidelines (2019). They cover synthetic fertilisers, organic amendments and crop residues, and are meant to be a practical and conservative way to count extra nitrous oxide.

## What a farmer group should start doing

- Log every fertiliser purchase and application, by field and date.
- Keep the same logbook before and after the switch, so the comparison holds.
- Do not change fertiliser rates in the first season without noting it.

## What Senseible does here

Senseible does not issue or verify carbon credits and is not a registry. It gives carbon credit eligibility signals from your own records and keeps those records in order for a verifier. Verified here means rule checks passed against the evidence, not third-party assurance.

- [AWD methane calculation](https://senseible.earth/answers/awd-rice-methane-reduction-calculation)
- [VM0051 rice AWD projects in India](https://senseible.earth/answers/vm0051-rice-awd-project-india)
- [Carbon credits](https://senseible.earth/carbon-credits)

Sources: [ICVCM, Observations on category assessment: rice cultivation methane avoidance, part II (August 2026)](https://icvcm.org/wp-content/uploads/2026/08/Board-Observations_Rice_II_VCS_VM0051_v1.1.pdf)

Last reviewed 2026-11-04.