Construction and testing of the first commercial-scale SCANS unit for measuring soil carbon in the Australian red meat industry

Summary

Soil is the largest carbon pool that humans can directly influence, offering the greatest potential to deal with global warming. Carbon storage in soil can improve the productivity, profitability, drought tolerance and biodiversity of grazing land.

CSIRO developed a prototype soil core scanning system (SCANS unit) to measure soil organic carbon. Through this project, MLA assisted the development of a practical, fast, non-destructive soil analysis test and software to effectively estimate soil carbon yield in Australian grazing land.

The SCANS had repeatable, accurate results, however, the cost of processing soil through the unit is around 15% higher than current laboratory analysis. Therefore, more development is required before the SCANS unit can be commercialised due to its low speed and higher costs.

Objectives

The objectives of the project were to:

• construct and test the SCANS unit in the field
• test the system's accuracy and repeatability at a commercial scale
• complete statistical analysis of the soil scan data to determine potential soil carbon yield.

Key findings

• The SCANS unit is twice as precise and shows more accurate results than the commercially available LECO soil analysis instrument.
• The SCANS unit is still only in the prototype stage, as it is too slow and costly to use commercially.
• If the carbon emission price is $25/tonne, farm profitability will increase when soil has carbon sequestration rates above 2 tonnes of carbon per hectare per year.
• The factors that most affect the profitability of a soil carbon project are the annual rate of carbon storage, the size of the project and the price of carbon at the time of sale.

Benefits to industry

On-farm soil carbon projects that focus on carbon storage can be a very profitable addition to a grazing business if the right practice changes are made, including:

• cropping multi-species pastures
• using deep-rooted legumes, such as desmanthus and leucaena
• restoring water retention through landscape rehydration.

MLA action

MLA is continuing to work with industry to develop accurate, affordable and scalable soil carbon measurement methods. This work is occurring through partnerships with technology companies and research organisation via the MLA Donor Company.

Future research

Improvements are required with the SCANS system to restrict water and gravel contamination in the soil samples and correct problems with gamma radiation. It is recommended the LECO system is used until the SCANS unit improves in accuracy and reduces in cost.