Extractants | Ratio(w/v)/Time/Temperature | Pool | Reference |
1 M NH4Cl | 1:6/16h/room temperature | Neutral salt soluble/exchange | [12] |
0.005 M DTPA | 1:2/2h/room temperature | Chelating, extractable | [13] |
1 M HCl | 1:33.3/2h/room temperature | Weak acid extractable | [14] |