Carbon farming: liming and carbon sequestration

Page last updated: Monday, 30 October 2023 - 9:15am

Please note: This content may be out of date and is currently under review.

Acid soils cause significant losses in production and biomass, which restricts the ability to sequester carbon. Applying agricultural lime to these problem soils can correct acidity levels that restrict root growth and crop and pasture production.

The Department of Primary Industries and Regional Development provides this information to support land manager decisions about investing in carbon farming.


Acid soils – pHCa below the targets of 5.5 at the surface and 4.8 in the subsoil – limit the potential for plant growth and biomass production. This in turn limits the buildup of soil organic carbon. Soil organic carbon levels are higher in areas of higher rainfall and higher biomass production, on soils that are unconstrained by water availability and contain more than 5% clay. See the soil acidity page for more information.

Liming is a cost-effective way of removing an acid-soil constraint to plant growth, resulting in greater biomass production, and increased soil organic carbon. However, liming adds carbonates that break down in acid soil to produce CO2.

Liming is an activity covered in the Measurement of soil carbon sequestration in agricultural systems method, and is a restricted activity (section 12:4) in the legislation. The requirements for a project to claim carbon credits from the Emissions Reduction Fund are very detailed, and include standard calculations of COreleased from carbonates.

Liming also:

  • decreases N2O fluxes from a wheat–wheat rotation, but not a lupin–wheat rotation
  • decreases total N2O fluxes by lowering fluxes following summer–autumn rain
  • increases CH4 uptake from a wheat–wheat rotation (Barton et al 2013)

Benefits from liming for carbon sequestration

Co-benefits of liming acid soils are improved production and improved nutrient efficiency allowing lower fertiliser costs.

Opportunities for liming:

  • About 80% of the grainbelt has soils that are too acid for optimal production of conventional agriculture. Reducing acidity would improve yields over a large area.
  • Liming acid soils improves the effectiveness of added fertilisers, and reduces costs of fertilising at optimum levels.

Risks from liming for carbon sequestration

Risks from liming specifically for carbon benefits:

  • Biomass and organic material incoporated into the soil must increase significantly to overcome the next point. That is, agronomic practice must also improve to capture the potential productivity gain of the soil.
  • Improvements in soil organic carbon are usually slow, require annual management to realise the potential productivity gain; and are sensitive to seasonal conditions and climate change.
  • Leakage (carbon dioxide emissions) can occur by carbonate lime dissolving and releasing bicarbonate which evolves into carbon dioxide and water.
  • The monitoring and reporting requirements for this type of project are onerous.


Barton, L., Murphy, DV and Butterbach-Bahl, K, 2013, 'Influence of crop rotation and liming on greenhouse gas emissions from a semi-arid soil', Agriculture, Ecosystems & Environment, vol. 167, pp. 23–32.

Contact information

Tom Edwards
+61 (0)8 9083 1151