Soil properties Low organic soil High organic soil
pH (H2O) 6.58 ± 0.44 6.32 ± 0.08
Organic matter (%) 4.16 ± 0.27 25.49 ± 0.48
Clay (%)  < 2μm 15.19 0.14
Silt (%)  2-50μm 78.69 7.17
Sand (%)  50-2000μm 6.12 92.69
Background Cu concentration (mg/kg) 23.26 ± 4.72 23.57 ± 3.51
Background Zn concentration (mg/kg) 121.55 ± 6.34 125.34 ± 26.71
Table 2: General properties and background metal concentrations in high and low organic soils.