preliminary soil salinity assessment - Mid Western Regional Council

Each soil pit site was recorded using a hand held GPS to provide an accurate reference of the samplelocations. The GPS coordinates for the samples sites are provided in Table 9: Soil Profile Sites GPSLocations.TABLE 9: SOIL PROFILE SITES GPS LOCATIONSSite NameGPS CoordinatesSite 1 E 740894 N 6391807 Zone 55Site 2 E 740891 N 6391986 Zone 55Site 3 E 740840 N 6392017 Zone 55Site 4 E 740849 N 6392186 Zone 55Site 5 E 740992 N 6392045 Zone 55Site 6 E 740980 N 6392090 Zone 552.6.2 Soil Sampling MethodologySoil pits were excavated using a 4 tonne excavator to approximately 1.3m at the six sample sitesreferred to as Sites 1 – 6. Observations of the soil profile were made and soil samples taken fromupper subsoil (B Horizon) and lower subsoil (C Horizon) within each pit except Site 2. Site 2 subsoilwas sampled as an aggregated sample of the upper and lower subsoil as the profile had blackbitumen like gravel and concrete chips found throughout the profile indicating the profile may havebeen previously disturbed and mixed through earthworks or construction work (discussed previouslyin Section 2.5.2). At Sites 1,2,3,4,and 6, ten (10) topsoil cores were also taken at 1m intervals along atransect in an easterly direction from each soil pit to a depth of 10 - 20cm depending on the depth ofA Horizon at the site. These cores were aggregated to provide a representative sample. The topsoilat Site 5 had to be taken from the pit as recent earthworks had disturbed all of the topsoilsurrounding the site. The topsoil and subsoil layer depths sampled at each site are provided in Table10: Soil Sample Depths.TABLE 10: SOIL SAMPLE DEPTHSSoil Sample SiteNameTopsoil Layer Depth(cm)Upper Subsoil Layer Depth(cm)Lower SubsoilDepthSite 1 0 – 15 15 – 35 35 - 100Site 2 0 – 10 10 – 100-(B & C Horizons)Site 3 0 – 10 10 – 30 30 – 100Site 4 0 – 15 15 – 40 40 - 110Site 5 0 – 20 20 – 60 60 - 130Site 6 0 – 20 20 – 70 70 - 130Samples were stored in sterile sealed bags. One sampler performed all collection procedureswearing clean disposable gloves at each site. Sampling equipment was cleaned after sampling ofeach site to prevent cross contamination of samples. The 17 soil samples were then taken from thesite and laboratory tested.Soil sampling was performed by Minespex on the 15th May 2012 (Sites 1 – 4) and 3 rd July 2012 (Sites5 & 6). One (1) duplicate soil sample was collected during this sampling event.PRELIMINARY SOIL SALINITY ASSESSMENT15