TERN Ecosystem Surveillance: Soil Subsite Sample 

This dataset comprises a comprehensive archive of soil subsite samples collected from TERN Ecosystem Surveillance monitoring plots across Australia. In addition to the 1-meter soil pit, soil subsite samples are taken from nine locations across the 1-hectare monitoring plot from three depths (0-10cm, 10-20cm and 20-30cm). Each of the nine subsites are selected to represent the variation in micro habitats across the monitoring plot. Collected following the standardised Ecosystem Surveillance methodology, the dataset includes over 33,600 soil subsite samples archived in the TERN Australia Soil and Herbarium Collection, located at the University of Adelaide's Waite Campus. Each record includes detailed metadata such as voucher barcode for soil collected from the three depths at each of the nine subsites, site and visit information and sampling details. Soil subsite samples are accessible and available for loan upon request through the EcoPlots Samples portal via an Expression of Interest. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. Datasets funded by TERN include the following statement “This work was jointly funded by the Terrestrial Ecosystem Research Network (TERN), an Australian Government National Collaborative Research Infrastructure Strategy (NCRIS) project. 

TERN Ecosystem Surveillance is a national plot-based field monitoring program that tracks the direction and magnitude of change across Australia’s major biomes. Information on soils and vegetation is collected according to standardised, widely endorsed and consistent protocols across all plots, and includes the collection of soil and vegetation samples and specimens for subsequent analysis. TERN soil subsite samples are collected from across the TERN Australia network of 960 monitoring sites nationally, with 410 plot revisits. Large areas of Australia lack sufficient soil information, TERN Ecosystem Surveillance address this gap by collecting standardised soil characterisation information and associated soil samples. Soil subsite samples are made available to researchers for future ecological and environmental studies and can be used for physical and chemical analysis, contributing valuable data to national and international soil information systems. Within each 1-hectare monitoring plot, soil subsite samples are collected from nine systematically distributed locations. This sampling design captures variability in vegetation cover and landscape position, ensuring the samples represent the spatial heterogeneity of the site. The soil subsite samples can be analysed using a range of methods, such as wet chemistry, mid-infrared (MIR) or near-infrared (NIR) spectroscopy. Analyses may be conducted on individual subsites to assess within-plot variation, or subsamples can be bulked and analysed to provide an average value across the monitoring plot. Generally, the quantities allowable for loan are selectable from the following categories (0-10g, 10-20g, 20-60g, 60g-100g). The quantity required for loan will depend on the type of analysis required. The TERN soil pit samples are all archived in the TERN Australia Soil and Herbarium Collection. 

Soil subsite samples are collected from nine subsites within each monitoring plot, with pits dug to a depth of 30 cm and samples collected at 10 cm intervals. Five of these subsites are positioned within a 25 x 25 m area in the southwest corner of the plot, selected to represent the full range of vegetation types, cover classes, and litter conditions. The remaining four subsites are distributed across the broader plot to capture additional variation in vegetation structure and ground cover. A bulk sample is also created by combining the 10 cm interval samples from all nine subsites. Soil subsite samples can be used for physical and chemical analyses. Before storage, samples are oven dried at 40 ^oC for approximately 48 hours, sieved, ground and then stored in sealed containers. Samples are organised by plot location and stored at ambient temperature conditions in the TERN Australia Soil and Herbarium Collection. For the three 10 cm intervals at the nine subsites, ~500g of soil is collected, a total of 27 subsite samples for a plot. For detailed methods on soil subsite sample collection, refer to the AusPlots Rangelands Survey Protocols Manual.