Soil sample Soil water content Organic carbon /(mg/g） Available nitrogen/(mg/g） Available phosphorus /mg/g） pH Site A 59.38 ± 0.070 17.60 ± 0.42 1.19 ± 0.02 1.51 ± 0.03 6.65 ± 0.03 Site B 60.23 ± 0.10 14.10 ± 0.23 0.86 ± 0.01 1.18 ± 0.03 6.69 ± 0.02 Site C 83.54 ± 0.04 76.50 ± 0.34 0.35 ± 0.02 1.17 ± 0.02 6.46 ± 0.03 Soil sample K/(mg/g） Ca/(mg/g） Mg/(mg/g） Fe/(mg/g） Cd/(mg/Kg） Cr/(mg/Kg） Cu/(mg/Kg） Site A 19.0 ± 0.21 177.54 ± 0.78 17.05 ± 0.37 46.01 ± 0.67 0.487 ± 0.14 81.34 ± 2.86 32.61 ± 1.7 Site B 19.0 ± 0.19 190.08 ± 0.89 17.05 ± 0.23 44.97 ± 0.43 0.707 ± 0.12 73.57 ± 0.66 26.81 ± 0.17 Site C 7.40 ± 0.20 18.73 ± 0.05 15.09 ± 0.43 23.30 ± 0.04 0.310 ± 0.00 66.60 ± 0.02 11.60 ± 0.01

Table 1: Analysis of physico-chemical parameters (amount of water content, organic carbon, available nitrogen, available phosphorus and Ph) and total concentration of metals [K, Ca, Mg, Fe, Cd, Cr, and Cu] determined from the three different soil samples collected at the city of Lanzhou. Shown are mean values (n=3) ± standard errors.