An introduction into soil carbon and carbon farming
What is carbon farming?
Carbon farming involves managing land to remove and store carbon from the atmosphere in soil (sequestration) or plants. Soil is the largest terrestrial carbon sink (place where carbon can be stored) over which we have control, and farmers as owners of large amounts of land are the key to improving soil carbon on a large scale. Soil carbon sequestration has the potential to help the planet regain its balance and help the landscape regain its health.
What is soil carbon?
Soil carbon refers to carbon stored in soil as organic matter from decomposed plant and animal residues. It plays a crucial role in soil health and can act as a carbon sink, helping mitigate climate change by storing carbon that would otherwise be released into the atmosphere.
What is the ACCU scheme?
The Australian Carbon Credit Unit (ACCU) Scheme encourages people and businesses to run projects that reduce emissions or store carbon, for example by:
- changing business practices to improve productivity or energy use
- changing the way vegetation is managed.
- upgrading equipment
- using new technology
Soil carbon projects are registered under a methodology called Estimation of Soil Organic Carbon Sequestration using Measurement and Models (2021 Soil Carbon Method). Agricultural operations can receive carbon credits using this method if they implement new activities to build soil carbon on their land and record measurable increases in soil organic carbon.
What are the benefits of increased soil carbon levels?
Increasing soil organic carbon levels offer the potential to create more resilient and productive soils through enhanced soil nutrient availability, water holding capacity, and microbial activity.
Soil carbon enhances nutrient retention by acting as a sponge, holding onto essential nutrients such as nitrogen, phosphorous, potassium, and other micronutrients. This improves their availability to plants, reducing leaching losses and making nutrients more available over time. Additionally, organic matter, where soil carbon resides, facilitates the gradual release of nutrients as it decomposes. This slow-release mechanism aligns with plant nutrient demand, promoting sustained growth and decreasing the necessity for frequent applications of fertilisers.
Carbon rich soils have improved structure and aggregation, facilitating enhanced water infiltration and retention capabilities. This dual effect boosts water holding capacity within the soil profile and reduces surface runoff and erosion risks. Higher soil carbon levels enable soils to retain more water between rainfall or irrigation events, creating a reservoir of moisture that sustains plant growth during dry spells.
Carbon-rich environments support increased microbial diversity and activity, fostering a wide array of bacteria, fungi, and other organisms essential for nutrient cycling, organic matter decomposition, and disease suppression in soils. These active microbial populations enhance soil health by breaking down organic matter and releasing nutrients in forms readily available to plants. Moreover, their interactions with plant roots and secretion activities contribute significantly to improving soil structure and overall health, reinforcing the vitality and resilience of agricultural ecosystems. Moreover, their interactions with plant roots and secretion activities contribute significantly to improving soil structure and overall health, reinforcing the vitality and resilience of agricultural ecosystems.
I’m already doing best practice; can I still sequester soil carbon?
Absolutely! Even with best agricultural practices, there are ways to further enhance soil carbon sequestration. Some of the many strategies include altering grazing management, reducing tillage, integrating cover crops into rotations. Applying inoculants or bio stimulants can contribute to increasing soil carbon levels. These practices not only support soil health and fertility but also help mitigate climate change by storing carbon in the soil, making your farm more resilient and sustainable in the long term.
How deep can soil carbon be sequestered?
At AgriProve we conduct all soil sampling to a depth of 1m. We split our soil analysis into two horizons, above and below 30cm.
Building soil carbon below 30cm is achievable with appropriate management practices and a commitment to improving soil health and sustainability.