Vision
The My Healthy Soils Project aims to empower residents with the knowledge, skills and tools to transform their urban yards from carbon sources to carbon sinks while creating a cool, healthy and more sustainable living environment.
Background
Soil and terrestrial vegetation are carbon sinks with around two thirds of the terrestrial carbon pool sequestered in soil (ASOE,2021). Charcoal a.k.a. biochar is a form of resistant carbon which naturally makes up around 10% of soil organic matter with humus e.g. compost/mulch making up 50% and particulate making up about 2-25% (DPIRD, 2022). Clearing, development and management of land for intensive landuses such as agriculture and urban have resulted in the loss of significant amounts of terrestrial carbon with Australia listed as number 3 (behind China and the United States) among countries with the highest loss of soil organic carbon (SOC) (ASOE, 2021). At the same time the processes that have enabled replenishment of soil organic carbon have been lost.
Significant efforts are being made particularly in the agricultural sector to restore terrestrial carbon, however, in the urban environment this is largely ignored. The My Healthy Soils project aims to empower local residents and others to increase soil organic carbon and health while providing other benefits including recovering resources from organic waste, reducing water use and improving plant health and associated vegetation and canopy cover.
Soil organic carbon in the 0-5cm layer in the City of Vincent
The project has drawn inspiration from three other projects. The first is a recent study: Soil health and carbon storage in community gardens in the Perth metropolitan area, Australia by Zhao et al. (2024) which identified significant improvements in total carbon and associated soil health parameters (e.g. soil water holding capacity, microbial activity, water repellence) because of the use of compost in the sandy soils of these gardens. The second is the Stockholm Biochar Project which aims to make Stockholm the world’s first urban carbon sink and to have 100,000 residents using biochar by 2020. Many other cities and towns are now following Stockholm’s lead. Biochar, a form of charcoal (a resistant form of carbon), has been used extensively by the City of Stockholm and its residents in conjunction with compost to improve soil fertility and water holding capacity resulting in significant improvements to tree health and canopy cover and water management. The third project is the Transition Town Vincent (TTV) community food forest located at the north west corner of Floreat Athena playing fields. Drawing on lessons from the Stockholm project in particular, the food forest trees have survived and thrived during a record breaking long hot summer due to the addition of organics (FOGO compost, biochar, worm juice) at the time of planting.
Problem and opportunity assessment
Western Australia’s population is forecast to grow from about 2.7 million to up to 5.6 million by 2056 (State Planning Strategy, 2014). The majority of these people will be housed in urban areas with significant investment being made to transform both infill and greenfield areas to house this population on land devoid of carbon and nutrients but requiring healthy soils and vegetation to mitigate urban heat island effects and a warming, drying climate.
Low levels of soil organic carbon (SOC) and organic matter (SOM) in urban soils and gardens are contributing to high levels of water use, poor plant health and sub-optimal tree canopy cover. With a regenerative and circular approach to the management of organic resources, urban gardens can be transformed from a carbon source to a carbon sink, resulting in healthier soils providing a range of benefits including better water management and healthier plants and canopy cover. Achievement of this outcome will require those all those responsible for management of urban soils to be provided with the required resources, knowledge, skills and support.
Transition Town Vincent (TTV) is a community based organisation which has been established in the City of Vincent for 10 years where it has been at the forefront of civic leadership and empowerment related to sustainability. Recent projects have included the community composting station (replaced by FOGO), the tools n things library, movie nights and the food forest. In addition to providing a cluster of community leadership and extensive networks, the TTV is located in an area which provides a local resource hub /circularity precinct for servicing the project. Similarly, it has an extensive network across the Perth region and WA regional communities.
The project initially aims to engage with residents in the vicinity of the existing circularity hub / precinct to implement best practice soil health enhancement practices using organics including compost, biochar, mulch and liquid biofertiliser e.g. worm juice. In addition to increasing soil carbon, other outcomes expected include healthy carbon sequestering gardens with healthy green / canopy cover and reduced irrigation requirements. The project will support these residents in improving the carbon content and health of their soils and gardens and will develop a scalable model for empowering residents to incorporate organics into their gardens / verges.
Resources
See the resources page for links to information and resources including videos about urban areas as carbon sinks and the use of biochar in particular.
Contact
Email: ian.kininmonth@ttv.org.au