# How much soil carbon can a CCTS afforestation project claim under tool BM-T-AR-0006?

Canonical: https://senseible.earth/answers/ccts-afforestation-soil-carbon-tool

The tool assumes soil carbon rises from its pre-project level to the native forest reference over 20 years, at a constant rate capped at 0.8 t of carbon per hectare a year. Reference stocks and change factors are IPCC defaults, and disturbing over 10% of a stratum costs 10% upfront.

## When the tool applies

- Not on wetlands or organic soils.
- Not on land already under the high-input or improved practices the tool lists, such as well managed, non-degraded grassland.
- Litter stays on site.
- Soil is disturbed only for site preparation, along the contours, and not again within 20 years.

## The steps

1. Initial soil carbon = reference stock x land use factor x management factor x input factor.
2. If the project disturbs more than 10% of a stratum's area beyond the baseline, deduct 10% of the initial stock in the year of site preparation.
3. Yearly gain = (reference stock minus what remains) / 20, capped at 0.8 t C per hectare a year.
4. Multiply by area and by 44/12 to get t CO2.

## Defaults for Indian conditions

- Reference stock, top 30 cm, t C per ha: tropical dry 38 for high activity clay soils, 35 for low activity clay, 31 for sandy; tropical moist 65, 47 and 39; tropical wet 44, 60 and 66; tropical montane 88, 63 and 34.
- Land use factor for cropland cultivated over 20 years: 0.58 in tropical dry, 0.48 in tropical moist or wet climates.
- Low input factor: 0.95 in dry, 0.92 in moist climates. Severely degraded grassland: 0.70.

## Worked example: 100 ha of old cropland, tropical dry

- Initial stock: 38 x 0.58 x 1.00 (full tillage) x 0.95 (low input) = 20.9 t C per ha
- Gap to reference: 38 minus 20.9 = 17.1 t C per ha
- Rate: 17.1 / 20 = 0.85, capped at 0.8 t C per ha a year
- Per hectare: 0.8 x 44/12 = 2.93 t CO2 a year
- 100 ha: about 293 t CO2 a year for 20 years, before other deductions

Land and soil type are illustrative; use your own soil classification.

## What Senseible does here

Senseible gives carbon credit eligibility signals from your records; it does not register projects or issue credits. It keeps dated, fingerprinted fuel and electricity invoices that a project's monitoring records can draw on.

- [Afforestation CCTS credits](https://senseible.earth/answers/bm-fr05-002-afforestation-ccts-credits)
- [Soil carbon sampling depth](https://senseible.earth/answers/soil-carbon-baseline-sampling-depth)
- [Displaced farming leakage](https://senseible.earth/answers/ccts-afforestation-displaced-farming-leakage)

Sources: [BEE, BM-T-AR-0006 Tool for estimation of change in soil organic carbon stocks due to A/R ICM project activities (CCTS Offset Mechanism, version 1.0, 27 March 2025): Tables 4 to 7](https://beeindia.gov.in/WriteReadData/RTF1984/RTF-PDF-bab2189eb243ca93_1776061843.pdf), [BEE, Methodologies and Tools under the CCTS Offset Mechanism](https://beeindia.gov.in/view_content.php?lid=571&lang=1)

Last reviewed 2026-10-25.