Soil carbon can occur in organic and inorganic forms.
Organic = decaying plant material, soil organisms and microbes, and carbon compounds such as sugars, starches, proteins, carbohydrates etc.
Soil organic carbon makes up 58% of total soil organic matter and is measured by a laboratory test.
Inorganic = mineral-based, most commonly calcium carbonate.
Environmental factors determine the balance of organic and inorganic carbon in the soil. Soil organic carbon content is generally higher in cool, wet environments, whereas inorganic carbon is higher in semi-arid environments.
Soil organic carbon is roughly three times larger than the amount of carbon stored in vegetation and double the amount stored in the atmosphere.
Organic carbon stocks in Australian soils are much lower than the global average and have been identified as a critical area for improvement in Australian agriculture.
With the Australian red meat sector aiming to be carbon neutral by 2030, Is carbon neutrality becoming the new minimum standard? How can we manage and improve our soil carbon levels?
Capacity is a crucial element of successful change. There is a capacity for change in cropping and livestock systems across our region.
Reducing grazing pressure on pastures and preventing soil degradation through erosion, salinity, soil acidity, or alkalinity plays a significant part in soil carbon management. Management options that may increase soil organic carbon:
Soil carbon is closely related to various biological, chemical, and physical soil processes. Therefore, soil organic carbon is a ‘headline’ indicator for detecting a change in soil condition. Regular testing from the same positions provides a means to track changes in carbon storage and an opportunity for trading excess carbon credits.
Note: Trading carbon credits can be risky as soil carbon levels can fall significantly during drought. Your business may require those credits to maintain carbon-neutral certification.
Riverine Plains Inc. carried out the soil carbon project from 2012 to 2016. The project aimed to understand key drivers in managing carbon in farming systems through the publication of research and farmer case studies. Key findings from this project were that:
In 2018, Riverine Plains and Central West Farming Systems partnered with Mars Petcare to develop an industry program, to quantify greenhouse gas (GHG) emissions from wheat production, and identify avenues to support farmers in reducing emissions, with a focus on soil health.
The project has gained support from Kellogg’s, the Manildra Group, Charles Sturt University, Food Agility Cooperative Research Centre and Allied Pinnacle and is now known as the Cool Soils Initiative (CSI). The key aim of CSI is to support grain farmers in reducing GHG emissions, leading to increased long-term sustainability and yield stability through adopting innovative agronomic strategies to improve soil health. The latest GHG emission results are available in the September Riverine Plains Newsletter. Increasing soil carbon levels will help neutralise the impact of greenhouse gases released into the atmosphere.
Soil carbon | Environment, Land and Water | Queensland Government (www.qld.gov.au)
Soil: Carbon dynamics | Australia State of the Environment Report
State of the catchments 2010: Assessing the condition of soils in NSW - Technical report series