CF-LRP Case Studies

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Weelhamby Farm Biodiversity & Carbon Projects

Project Overview:

  • Recipient: Weelhamby Land Pty Ltd
  • Location: Perenjori, WA
  • Total funding: $738,600
  • Project size: 3200 hectares
  • Estimated ACCUs: 170,000
  • Project methods: Reforestation by Environmental or Mallee Plantings – FullCAM; and
  • Estimating soil organic carbon sequestration using measurement and models method.

Weelhamby Farm is in an area noted for its biodiversity significance and is surrounded on three sides by nature reserves. Due to past cropping and pasture management techniques that were not designed to support the build-up of carbon and soil health, sampling shows the average soil organic carbon on the land is currently very low. The project focuses on improving soil health and sequestering carbon in soil as priority outcomes from operating a profitable agricultural production enterprise across at least much of the land.

The project will see the adoption of new management practices, including a three-year pasture to one-year cropping rotation, with pulse grazing of pastures by sheep to improve soil microbial and fungal activity, water infiltration and water holding capacity in the soil, and build soil organic carbon in the top one metre of soil on farm in the next 25 years. Around 250 ha of biodiverse revegetation plantings in belts around the farm are also designed to increase productivity and biodiversity.

The project will provide significant agricultural, biodiversity and landscape management co-benefits. Weelhamby is intended as a public demonstration farm, hosting field days, and regularly sharing updates and economic outcomes with the agricultural community.

Proponent David Martin provided an update at the Round 2 Announcement Forum: 

View the project update and listen to the audio of the presentation below:

 

Biodiversity Project (230 ha)

The plantings will provide multiple on-farm co-benefits, including windbreaks to reduce wind erosion, shelter for stock, and increased water infiltration by slowing the movement of water across the landscape.

The revegetation program will be implemented using manual and machine tube stock planting and direct seeding of understory species. A biodiversity baseline report will guide decisions on optimal planting areas, supported by a detailed landscape analysis.

There will be a combination of small block plantings on areas of the farm not suited to agriculture and adjacent to existing remnant vegetation on the property to extend habitat for mallee fowl and other threatened species. Wide belt plantings along existing and new fence lines to create wildlife corridors linking 1,500 ha of remnant vegetation with the three nature reserves adjoining the property. The belts will also divide existing paddocks into smaller grazing areas (cell grazing).

An independent ecological assessment will verify landscape connectivity values as part of the proposed 3-year outcomes report, in addition to reports measuring the impacts and outcomes of both projects every 3-5 years.

Weelhamby project site
Weelhamby project site
Soil Carbon Project (3,200ha)

One of the aims of this project is to build soil organic carbon over the next 25 years. The farmer chose an independent agronomist with extensive local experience to support the project. The farmer and the agronomist worked together to design a new land management strategy, shifting from high input cereal cropping, towards a rotational grazing enterprise with multi-species perennial pasture. A biological inputs program was also implemented.

The proponent will use annual farm management records as a data source to benchmark the project’s performance against historical measures such as stocking rates, crop yields, fertilisers and other inputs (mineral, chemical and biological).

Soil and salinity impacts will be measured by mapping the extent, location and severity using satellite imagery and electromagnetic induction. Avoided loss of topsoil from wind and water erosion will be achieved through year-round ground cover, as well as minimisation of water run-off and increasing the water holding capacity of the soil.

This project will re-establish pasture by seeding a mix of annual and deep-rooted perennial grasses and legumes to encourage and facilitate significant build up in soil microbial and fungal activity. The planting of multi-species pasture crops will include perennial grasses and legumes across all grazing areas. The addition of legumes to the mix of seeds sown is to be a significant change for the property and is expected to make a positive difference to available soil nitrogen levels.

The project estimates that it can increase soil organic carbon levels from 0.7% to 1.2% in the top 30cm. The project has nominated a 100-year carbon permanence period, which will allow for the creation of long-term carbon and environmental outcomes.

2023 Project Updates

Approximately 90% of the cleared land on the farm has been included in the project; the soil project area will cover around 81% of the property, and the vegetation project, combined with a buffer zone, laneways and areas unsuitable for farming making up the remaining 9%. Across the vegetation project area, 70,000 seedlings have been planted using a combination of machine, hand, and direct seeding across 233 hectares. Over 350 soil samples have been collected to create a baseline and understanding of the property’s soil.

A biodiversity baseline was commissioned by ecologist Dr Judith Fisher across remnant vegetation and some areas of pasture, and a biodiversity database has been created using a combination of drone and digital technology. The project proponent held a site visit to identify ideas of cultural significance with Traditional Owners, Yamatji Southern Regional Corporation Ltd (YSCR) and a representative from the Department of Planning, Lands and Heritage (DPLH).

Across the soil project, a combination of pastures and crops were seeded, including serradella, corn rye, safflower, canola, wheat, oats, vetch, lupins, and linseed. Several treatments have been added across the soil project area, including microbial and fungal seed dressings, organic compost, lime and guano. In addition to plantings, Weelhamby Farm gained Elders’ ‘Responsible Wool Standard’ (RWS) Certification and will be fully certified organic in 2024, with much of the farm already certified.