Soil samples S1 S2 S3 S4 S5 S6 S7 S8
First Crop harvest Amaranthus Amaranthus Amaranthus Amaranthus Amaranthus Amaranthus -------- --------
Growth period 30 days 30 days 35 days 45 days 45 days 55 days -------- --------
Soil type (0-15cm) pH 1:1 5.9 6.1 6.3 6.5 6.7 6.9 6.7 6.9
EC 1:1 dS/m 0.32 0.48 0.45 0.52 0.38 0.44 0.46 0.47
NO3 –N mg/kg DW 21.9 25.1 22.4 28.0 39.5 33.3 56.3 57.8
NH4-N mg/kg DW 2.66 2.72 2.48 3.16 3.11 2.72 4.83 5.25
% Pb uptake 27.5 27.7 29.1 32.1 28.6 27.9 ----- -----
% Cd uptake 12.9 13.2 14.3 14.1 14.1 13.5 ----- -----
% Zn uptake 9.42 10.24 9.82 8.43 8.50 8.11 ---- -----
% Ni uptake 6.36 7.11 6.53 5.18 5.98 5.99 ----- -----
%  Cu uptake 11.95 11.55 11.06 10.76 10.62 10.20 ----- ------
Table 2: The characteristics of soil samples and their potential of uptake heavy metals comparing with their pH.