Lead Investigator: Dr Michael Franklin (WSU) & Associate Professor Uffe Nielsen (WSU)

Co-Investigators: PhD Candidate Dylan Bristol (WSU)

Project Summary: In early March 2024, the NSW Department of Planning and Infrastructure contracted researchers at the Hawkesbury Institute for the Environment, Western Sydney University, to design and implement a sampling program to establish the current state of soils at their proposed reconstruction site at Appin, NSW. The brief was to sample and analyse soils in the site and surrounds to guide the development of the restoration concept plan and provide a baseline for future research conducted in association with restoration methods. In mid-March 2024, soil samples were collected from 30 plots in the reconstruction site and from 10 reference plots in surrounding bushland. At each plot, soil was sampled from two depths at four different points within the plot. Key physical and chemical properties of the total set of 320 soil samples were subsequently analysed at WSU laboratories. The soils across the reconstruction site were enriched in organic matter, had higher carbon, nitrogen and phosphorus (total and Colwell-P) contents, and higher pH reflecting past land use. In contrast, soils in the reference bushland sites were more acidic and had lower carbon and nutrient content. The use of a 100 x 100 m grid for sampling allowed unbiased mapping of restoration site conditions at a reasonable resolution without excessive sampling and costs for analyses. These results provide a robust platform for planning restoration interventions and ongoing monitoring at the site. The approach taken to designing this baseline soils study may be applied at other similar candidate reconstruction sites.