Wirchilleba Soil Carbon Project

The Wirchilleba Soil Carbon Project is a soil carbon sequestration initiative located on Wirchilleba Station, approximately 100km south of Cobar in the Central West region of New South Wales. Registered in March 2025, the project covers 5,238 hectares of land situated near the locality of Gilgunnia. The station is positioned within the Cobar Peneplain, an area traditionally utilized for rangeland grazing of sheep and cattle, as well as opportunistic cropping.

The project operates under the Carbon Credits (Carbon Farming Initiative, Estimation of Soil Organic Carbon Sequestration using Measurement and Models) Methodology Determination 2021. This methodology requires the proponent to establish a baseline of soil organic carbon (SOC) through physical sampling, implement new land management activities to sequester carbon, and then measure the increase in SOC over time to generate Australian Carbon Credit Units (ACCUs). Specific activities on Wirchilleba include altering stocking rates to improve ground cover, rejuvenating pastures through seeding, retaining stubble from crops, and introducing legumes into the grazing system to boost soil nitrogen and organic matter.

Environmentally, the region is characterized by a semi-arid climate with variable rainfall, making soil moisture retention a critical focus for land management. The soils in this area are typically red earths and lithosols derived from the underlying Wirchilleba Granite and Cobar Superbasin geology. These soils can be fragile and prone to erosion if vegetation cover is lost, which aligns with the project's goal of improving soil health and vegetation density.

The proponent, Manuka (Cobar) Pty Ltd, is a subsidiary of Manuka Resources Ltd, a mining company that operates the nearby Wonawinta Silver Mine. This suggests the project represents a strategic dual-use of land assets, where mining tenure or associated pastoral holdings are leveraged for carbon abatement alongside extraction or grazing operations. The property has a rich history, having been held by notable pastoralists such as Arthur Bryant Triggs in the early 20th century, and has been described as "red-dirt country" with deep historical ties to the region's gold and copper mining heritage.