Soil is often referred to as the ‘biggest carbon sink on earth that we have control over’. But how exactly can soil carbon benefit farmers?
To answer this question, we should first ascertain how carbon abatement actually works in the soil.
The process begins with photosynthesis where plants absorb carbon dioxide to create plant matter, and ends, practically speaking, with plants adding carbon to the soil when they expire. From a climate mitigation perspective, soil carbon is a store of trapped emissions, that add biological benefit to the soil and are unable to be absorbed into the atmosphere as a greenhouse gas. Due to historical land use practices, it’s estimated that soil carbon has declined between 20 and 60 per cent in once-vegetated Australian soils that are now used for agriculture.
The benefit to farmers from increasing soil carbon is profound in a direct improvement in the productivity and resilience of their property. And Soil Carbon Projects incentivise the practice further—enabling land managers to earn carbon credits by storing carbon.
There are a number of ways to increase soil carbon, which include:
- Increasing the input rate of carbon, through the planting of vegetation or input of compost or mulch
- Changing fertilizer application and timing
- Altering irrigation methods
- Decreasing activities that cause carbon loss, such as stubble burning or vegetation clearing
- Changing grazing and tilling practices to reduce soil impact and disturbance
- Altering the soil profile to a composition that increases residence time of carbon in the soil, such as adding clay to sandy soils
One or a combination of these activities can markedly improve the productivity and resilience of managed land. Improvements to soil carbon are observable through improvements in nutrient and water retention in plants as well as soil function and fertility, all of which bear significant benefits to land managers.
In addition to their productivity and environmental benefits, Soil Carbon Projects earn carbon credits through the Climate Solutions Fund project (CSF) which builds upon the Emissions Reduction Fund (ERF) by allowing project managers to earn carbon credits and sell them into government or to private buyers.
Measurement of soil carbon Sequestration in agricultural systems methods can also come with an advance of $5,000 to support baseline sampling costs. After successful registration you move into a ‘crediting period’ and the ‘permanence period’. The crediting period allows project managers to start earning credits immediately, while the permanence period is selected at project registration and allows project managers to choose a 25-100 year commitment to retain the carbon stored by the project. By electing a 25 year permanence period, a project will receive a 25% reduction in carbon credits issued compared to a 100 year permanence period.