What is carbon farming?
Soil Carbon
Soils account for 75 per cent of carbon storage
Most of Earth’s carbon exists in the ocean. But on land, soils account for about 75 per cent of carbon storage. This ecosystem is why carbon farming is important.[1] Understanding current jargon around carbon emissions can be a little confusing but the basics are as follows:
Carbon neutral means that an activity releases net zero carbon emissions into the atmosphere.
Climate positive means that an activity goes beyond achieving net zero carbon emissions and creates an environmental benefit by removing additional carbon dioxide from the atmosphere.
Carbon negative means the same thing as “climate positive.”
Carbon positive is sometimes how organisations describe the previous two definitions. It’s mainly a marketing term.
Carbon Farming is a way of farming that captures and holds carbon in vegetation and soils to reduce greenhouse gas emissions. It seeks to reduce emissions in its production processes while increasing production and sequestering carbon in the landscape. This is achieved through managing land, water, plants, and animals to meet the triple challenge of landscape restoration, climate change, and food security.
Carbon Farming can range from a single change in land management, such as introducing no-till cultivation or grazing management, to a whole-of-farm integrated plan which maximises carbon capture and emissions reduction.[2]
Soil carbon is the carbon stored in the soil as a component of organic matter in various stages of decay. It has been identified as an important tool to mitigate climate change as soil stores more carbon than the atmosphere and terrestrial biomass (trees) combined.[3]
Soil carbon is directly related to agricultural productivity. Increasing carbon stocks improves water holding capacity, nutrient availability and soil fertility. This is beneficial for broadacre, horticulture and irrigation farming.
Soil carbon can be increased by:
1. Increasing the production of plant biomass. This creates a positive feedback loop: increased soil carbon can boost plant growth, and more plant growth can increase soil carbon.
2. Decreasing losses, which includes things like reduced stubble burning or minimal till practices
Increasing the residence time of carbon in the soil carbon pool by changing the profile of organic matter added to soil in a form that decomposes more slowly, or in a way that is protected by the chemistry of the soil; things like increasing clay content in sandy soils.
4. When bolder management changes are made – such as land use change, rotational grazing, and replanting native vegetation – even higher rates of soil carbon accumulation are possible
Grazing increases soil carbon
The natural carbon cycle in soil begins as plants take in carbon dioxide (CO2) from the air. Plants use the carbon to make roots, shoots, and leaves. With the help of soil microbes, plants then transfer carbon to the soil through roots and decomposing residue. The stable storage of this carbon below ground builds soil organic matter, and it reduces levels of atmospheric carbon. The process is called carbon sequestration.
While the carbon cycle occurs naturally with varying degrees of efficiency in croplands as well as in grasslands – with or without grazing – grazing at moderate levels tends to increase the amount of carbon sequestered in grassland soils.
Drawing from her research and the research of other scientists, North Dakota grassland ecologist and science application educator Rebecca Phillips says, “We are finding plants put more carbon below ground as a result of the grazing of livestock. A well-managed grazing system stores more carbon in the soil than grasslands that are not grazed.
“The key is the activity in the plant roots,” she says. “Their response to grazing is to produce more roots and more exudates through the roots. Exudates feed the microbial population in the soil. In turn, microbes process the root materials, transforming them into forms used by microbes stored in soil – effectively improving the health of the soil to support plant growth. Grazing is one key to supporting healthy microbial communities in soil.”[4]
Many of these practices are now common in organic farming, regenerative agriculture, permaculture, and livestock farming.
[1] Farm | Just what is soil carbon?
[2] What is Carbon Farming? - Soil Carbon Industry Group (scig.org.au)
[3] Carbon Farming Basics – Precision Agriculture
[4] Livestock’s role in a changing climate | Successful Farming (agriculture.com)