Robson Creek Rainforest Soil Characteristic Data 2011 - 2014 

This data contains soil physico-chemical characteristics collected at the Robson Creek Rainforest site between 2011 - 2014. 

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. 

Data not provided. 

The collection of physico-chemical characteristics of soil from the Robson Creek Rainforest site was conducted between 2011 and 2014. The soil physico-chemical characteristics was described in 6 backhoe pits (each 2 m deep) over an area of about 8 x 8m, dug to assess the site for flux tower foundation. Soil samples were collected from the face of the pit for each layer :0.2 m, 0.5 m, 0.75 m, 1 m, 1.5 m, 2 m. Samples were air-dried to constant mass, sieved to 2 mm, roots and rocks removed and weighed. The samples were homogenised and sent off for analysis within 5 days. Sieved (<2mm) samples were analysed, using methods described by Rayment and Higginson (1992) for exchangeable Ca, Mg, K and Na (Method 15A1), exchangeable acidity and Al (Method 15G1), Colwell extractible P (Method 9B2), total C (Method 6B4), total N (Method 7A7), electrical conductivity (EC) and pH (both in 1:5 soil:water extract) and particle size distribution. As the soil has a high content of stones, the volumetric proportion of soil and rock was determined at several depths. The total volume of each depth increment was determined by pouring measured volumes of sand into a pit as it was excavated. The excavated soil was sieved (2 mm); and material passing through the sieve was called soil. Material that was retained on the sieve was mechanically tumbled for 45 minutes in order to break apart aggregates of soil and to separate soil from the rocks. The tumbled material was sieved again through a 2mm sieve and the material retained was separated into roots and rocks. All materials were weighed and the water content of the soil was determined. Using a calibrated 20L bucket, the volume of rocks (pre-wet to prevent loss of water by absorption) was measured. The volume of soil in each layer was calculated by subtracting rock volume from the volume of the excavated hole. To measure soil temperature and water content, 3 types of soil monitoring probes were installed, 8x CS229 probes to measure water tension, 9x CS616 TDR probes to measure volumetric water content, 1x TCAV probe to measure average soil temperature the probes were deployed in the loamy area of the pit (SW corner, S corner and SE wall). Four depths were reached: -100 mm, -750 mm, -1500 mm and -2000 mm. Per depth 3x TDR and 2x CS229 were deployed in a triangular pattern; vertically in columns 1m apart and numbered as I (SW corner), II (S corner) and III (SE wall, TDR only); the TCAV probe was deployed at -750mm between the columns. The TDR probes were pushed horizontally into the loamy soil (TDR III@-750mm had to be pushed into a mix of loam/coarse sand). The CS229 probes were laid down horizontally in close proximity (5-10cm) to the TDR probes in column I and II and buried in fine loam scraped from the walls at the spots; the probes weren't saturated with water before deployment. The TCAV probes were pushed into the soil horizontally (pairs 5cm vertically apart) in the SE wall and SW wall, half way between the columns I/II and II/III.