Agriculture & Soil Carbon
TNS v1.0 - Annex C
Agricultural soils represent one of Earth's largest and most accessible untapped carbon sinks. Through improved land management - cover cropping, reduced tillage, organic matter application, and grassland restoration - degraded soils can rebuild their organic carbon stocks while delivering transformational co-benefits for food security, water retention, and farmer livelihoods across the Global South.
Submit Soil Carbon Project View TNS v1.0 Annex C →How this pathway works
Soil organic carbon (SOC) sequestration through improved land management is among the most widely applicable carbon removal approaches available today. Agricultural soils worldwide have historically lost 50–70% of their original carbon content through intensive tillage, monoculture cropping, and overgrazing - creating a vast, verifiable opportunity for restoration where farming practices change.
Under the Teravent Nature-Based Carbon Standard (TNS v1.0) Annex C, Agriculture & Soil Carbon projects earn Teravent Nature Credits (TNCs) for verified, additional increases in soil organic carbon stocks relative to a monitored baseline. The project boundary must encompass all land units under management change, defined to a minimum spatial accuracy of five metres using GPS or remote sensing.
Five methodology variants are approved under Annex C - from cover cropping (ASC-M01) through grassland restoration to permanent pasture (ASC-M05). Each methodology specifies its own eligible practice changes, carbon pool accounting obligations, monitoring frequency, leakage assessment requirements, and permanence risk rating.
TNS v1.0 - Annex C
This pathway is governed exclusively by the Teravent Nature-Based Carbon Standard (TNS v1.0). No external registry, standard, or methodology is referenced or incorporated. All requirements - additionality, quantification, MRV, safeguards, and credit issuance - are defined within TNS v1.0 and Annex C specifically.
Five approved methodology variants
TNS v1.0 Annex C approves five discrete methodology types for the Agriculture & Soil Carbon pathway. Each code represents a distinct land management intervention with its own eligible practices, carbon pool requirements, monitoring frequency, and default leakage deductions. A project may combine multiple methodologies if all eligible practice changes are captured under separate accounting streams.
Cover cropping involves planting non-harvested crops (legumes, grasses, brassicas, or mixtures) during fallow periods between main cash crops. Cover crops contribute to SOC through root biomass deposition, above-ground residue decomposition, and rhizosphere carbon inputs. Leguminous cover crops additionally reduce synthetic nitrogen fertiliser requirements, generating a secondary N₂O emission reduction that must be separately quantified and credited only where independently verified.
- Soil organic carbon (% by dry combustion CHNS analysis) at permanent monitoring plots
- Bulk density (g/cm³) at each depth increment - required for tCO₂e/ha conversion
- Cover crop species, seeding date, termination date, and above-ground biomass estimate
- Fertiliser application records (type, rate, timing) for N₂O baseline comparison
- Crop yield records to verify food security co-benefit maintained
Reducing or eliminating tillage preserves soil carbon by minimising physical disruption of soil aggregates that protect organic matter from microbial decomposition. No-till (NT) and reduced-till (RT) systems also reduce soil erosion, improve water infiltration, and lower on-farm fuel consumption. The baseline must document the previous tillage practice (conventional, deep ploughing, or rotary hoeing) and the tillage-associated GHG emission savings are quantified as a secondary benefit alongside the primary SOC increase.
- Soil organic carbon at 0–30 cm and 30–60 cm at permanent plots (SOC can be redistributed by tillage)
- Tillage records - machine log or farmer declaration verified by VVB satellite imagery check
- Bulk density at each depth increment (may increase under long-term no-till without cover crops)
- Fuel consumption records for tillage energy savings secondary benefit quantification
- Weed management records - NT projects often shift to herbicide use, which must be assessed for DNSH compliance
Organic matter application projects increase SOC by adding exogenous sources of plant-available carbon - compost, farmyard manure, digestate, crop residues, or biosolids - to soils that would otherwise receive none or significantly less. The key accounting challenge is the 'carbon substitution' problem: if compost is diverted from another use where it would have decomposed and returned CO₂ to the atmosphere anyway, the net removal is lower than the quantity applied. Teravent requires a counterfactual fate analysis for all organic inputs to determine the baseline decomposition trajectory.
- Compost or organic matter quantity applied (t/ha/yr) with carbon content analysis (CHNS per batch)
- Counterfactual fate documentation - where would the input have gone without this project?
- SOC at permanent plots (0–30 cm; 30–60 cm where deeper incorporation expected)
- N₂O flux - measured at minimum 4 representative plots or calculated using IPCC Tier 2 emission factors
- CH₄ from composting operations (relevant where on-site composting is part of the project)
Introducing high-residue crops (sorghum, sunflower, cotton, pigeon pea, deep-rooted grasses) or deep-rooted legumes into existing monoculture or simple rotation systems increases carbon inputs to the soil profile beyond what the baseline rotation delivers. The additional carbon is attributable only to the incremental change in rotation design - the methodology requires a fully documented baseline rotation against which the project rotation is compared using the same model or empirical approach for both.
- Rotation sequence records (crop species, planting and harvest dates) per field unit - verified by VVB
- Above-ground crop residue quantity and C:N ratio (sampled at harvest)
- SOC at permanent plots, minimum every 3 years - compared against process model prediction
- Root biomass sub-sampling at minimum 20% of monitoring plots (0–60 cm) for deep-rooted species
- Fertiliser inputs - changes in synthetic N must be accounted for in GHG balance
Converting annually-cropped land to permanent grassland or native pasture is among the highest-sequestration soil carbon activities available, particularly on deeply degraded arable soils in dryland and semi-arid regions. Permanent grasslands accumulate carbon through extensive root systems, litter inputs, and reduced disturbance. The land use change must be legally committed and contractually secured for the full 10-year crediting period minimum. Projects must include a stocking rate management plan where grazing will occur on restored pasture.
- SOC at 0–30 cm mandatory; 0–100 cm strongly recommended for permanent pasture (deep root accumulation)
- Land use confirmation via satellite imagery (annual) and VVB site inspection (every 3 years)
- Stocking rate records (livestock units/ha/season) where grazing occurs
- Enteric methane estimate (livestock emissions) - must be deducted where stocking rate exceeds baseline
- Vegetation cover and species composition survey at commencement, year 3, year 5, and each 5-year interval
- Food security impact assessment - documents any loss of food production from converted cropland
Which pools must be counted
TNS v1.0 Module 3 requires all material carbon pools within the project boundary to be assessed. A pool may be excluded only where its inclusion would reduce the net carbon benefit (conservative assumption) and this is documented in the PDD. The following assessment applies to all five ASC methodology variants.
Measurement, reporting
& verification
Teravent's Science Advisory Board assesses each pathway against four MRV dimensions. These scores reflect the current state of measurement science for agricultural SOC and are updated as new field data, sensor technologies, and model validations emerge.
SOC measurement requires dry combustion analysis (CHNS elemental analyser) for total organic carbon content, combined with bulk density measurement (core ring method) at every depth increment to convert % SOC to tCO₂e per hectare. All laboratory analyses must be conducted by an ISO/IEC 17025 accredited facility. Sample archives must be retained for 10 years for re-analysis at VVB discretion. Where a process-based SOC model (RothC, CENTURY, or equivalent) is used, it must be calibrated against site-specific measured data from minimum 3 years of project monitoring before model-assisted estimation is accepted for credit issuance.
Demonstrating additionality
TNS v1.0 Module 2 requires all projects to pass a three-test additionality framework. All three tests must be satisfied. For soil carbon projects, the common practice test is particularly important given that cover cropping and reduced tillage are increasingly adopted across many regions for agronomic reasons independent of carbon finance.
Leakage types & deductions
TNS v1.0 Module 3 requires leakage assessment for all project types. Soil carbon projects are primarily subject to activity-shifting and market leakage. Default leakage deduction rates by methodology are specified in Annex C and must be applied unless the project demonstrates site-specific leakage is materially lower, subject to VVB verification.
Buffer pool & reversal risk
All Annex C credits carry Class I Biological permanence (10–100 year storage horizon). Buffer pool contributions protect credit buyers against reversal events - the unintended release of previously sequestered carbon to the atmosphere through drought, tillage resumption, or land use change. Buffer rates are set by the project's Non-Permanence Risk Rating (NPRR).
| Methodology | NPRR Rating | Buffer Pool Rate | Primary Reversal Risks |
|---|---|---|---|
| ASC-M01 Cover Cropping | Low–Medium | 20–30% | Drought; farmer withdrawal; reversion to conventional management |
| ASC-M02 Reduced / No-Till | Medium | 25–35% | Single tillage event can release years of accumulated SOC; weed pressure reversal |
| ASC-M03 Compost Application | Medium | 25–35% | Decomposition under drought or heat stress; input supply discontinuity |
| ASC-M04 Crop Rotation | Low–Medium | 20–30% | Rotation reversal; crop failure; market price shifts favouring monoculture |
| ASC-M05 Grassland Restoration | Medium–High | 30–40% | Land use change; overgrazing; drought; tenure dispute; commodity price pressure |
Key registration criteria
Projects must meet all of the following minimum requirements to qualify for registration under TNS Annex C. Additional methodology-specific requirements are detailed in the Annex C methodology tables for each ASC-M code.
Sustainable Development
Goal alignment
All Teravent registered Agriculture & Soil Carbon projects must complete an SDG impact assessment at registration and at each verification period. Six SDGs are systematically tracked for this pathway. Projects may apply for co-benefit quality labels where independently verified indicators are met.
Priority regions: Sub-Saharan Africa (Sahel, East Africa, Southern Africa) and South Asia (Indo-Gangetic Plain, Deccan Plateau) - where soil degradation is most severe, co-benefit value for communities is greatest, and transformation potential for smallholder livelihoods is highest.
Ready to register your
soil carbon project?
Submit a Project Concept Note under TNS v1.0 Annex C to begin your registration. Select one or more of the five approved ASC methodology codes, complete your baseline soil sampling, and appoint an accredited VVB to validate your PDD.