Table 2.
Physicochemical properties of three clustered soil groups and their pH buffering capacity before acid or alkali spills.
| Properties | Group 1 | Group 2 | Group 3 |
|---|---|---|---|
| No. of sample | 7 | 8 | 5 |
| OM (%) | 1.91 ± 0.67 | 2.68 ± 1.49 | 6.02 ± 1.87 |
| Clay (%) | 4.52 ± 3.32 | 17.86 ± 4.97 | 15.30 ± 5.02 |
| CEC (cmol kg−1) | 4.49 ± 3.17 | 16.54 ± 5.78 | 20.40 ± 3.57 |
| pHBC (mmol kg−1) | 14.85 ± 5.30 | 30.99 ± 7.92 | 61.49 ± 8.32 |
| Characteristicsa | Low OM Low Clay Low CEC Low pHBC |
Low OM High Clay High CEC Moderate pHBC |
High OM High Clay High CEC High pHBC |
Group 1 had the lowest organic matter and clay content, CEC, and pH buffering capacity among the three groups, whereas group 3 had the highest organic matter content, CEC, and pH buffering capacity. The organic matter content of group 2 was greater than that of group 1 (without statistical significance) but significantly lower than that of group 3. The clay content of group 2 was significantly higher than that of group 1 and higher than that of group 3 (without statistical significance). The CEC of group 2 was significantly greater than that of group 1 but lower than that of group 3 (without statistical significance). The pH buffering capacity of group 2 was significantly greater than that of group 1 but significantly lower than that of group 3.