University of Western Australia
Community gardens have been sprouting up all over Perth in recent years.
They provide a common space where people come together to grow food, foster good health, and green urban environments, support life-long learning and cultivate vibrant communities.
The University of Western Australia Honours student Haochen Zhao is examining soil health and carbon storage in community gardens located in the Perth metropolitan area.
His research project is supervised by Professor Nanthi Bolan and Dr Bede Mickan, and includes Perth City Farm, North Fremantle Social Farm, Murdoch Community Garden, West Leederville Community Garden, Earthwise Community and Glyde-In Garden Gnomes.
Image: UWA Honours student Haochen Zhao with Professor Nanthi Bolan.
Although community gardens primarily promote sustainable horticulture and conservation agriculture practices, Mr Zhao said research on soil health and carbon sequestration potential in community gardens was limited.
“Soil carbon sequestration contributes to mitigating the impacts of climate change resulting from greenhouse gas emission,” he said.
For this study, soil samples were collected from the six community gardens covering three Soil Mapping Units (calcareous deep sands, coloured sand, pale sands) including control plots (bare ground next to raised beds) and raised beds (gardening area).
Image: Plentiful crops growing at North Fremantle Social Farm.
Soil samples of raised beds and control plots were characterised for various soil physical, chemical and biological properties.
Soil carbon storage was then calculated based on bulk density and the total carbon content of the soil.
The soil samples from raised beds had lower bulk density and loamy texture.
They also had higher pH buffering capacity, available nutrients (including nitrogen phosphorus and potassium), cation exchange capacity, total carbon, and microbial biomass.
Mr Zhao said this indicated that soils in community gardens maintained higher soil health parameters.
“In addition, raised bed soils accumulated higher levels of carbon, indicating that community gardens provide a potential source of carbon sequestration,” he said.
“The improved soil health and carbon storage in community garden soil can be attributed to the regular application of compost produced within the community gardens.”