Table 4.
Data of principal component analysis (PCA) for soil quality variables.
| PCs | PC1 | PC2 | PC3 |
|---|---|---|---|
| Eigen value | 19.98 | 2.82 | 2.12 |
| Variance (%) | 71.36 | 10.06 | 7.58 |
| Cumulative variance (%) Eigenvectors | 71.36 | 81.42 | 89.01 |
| pH | − 0.730 | − 0.274 | 0.174 |
| EC | 0.968 | 0.573 | 0.097 |
| SAR | − 0.460 | 0.959 | − 0.261 |
| ESP | 0.206 | 0.911 | 0.011 |
| OM | 0.936 | 0.577 | 0.234 |
| CEC | − 0.672 | 0.503 | 0.477 |
| CCE | 0.777 | 0.239 | − 0.298 |
| Total N | − 0.768 | 0.514 | 0.308 |
| Available P | 0.812 | 0.238 | 0.253 |
| Available K | 0.273 | 0.55 | − 0.591 |
| Exchangeable Ca | − 0.070 | 0.259 | 0.848 |
| Exchangeable Mg | 0.351 | − 0.192 | 0.836 |
| Exchangeable K | 0.200 | 0.940 | − 0.034 |
| Exchangeable Na | 0.371 | 0.870 | 0.162 |
| Soluble Ca | 0.745 | 0.468 | 0.311 |
| Soluble Mg | 0.834 | 0.472 | 0.135 |
| Soluble K | 0.901 | − 0.276 | − 0.071 |
| Soluble Na | 0.695 | 0.651 | − 0.034 |
| Zn-DTPA | 0.734 | 0.639 | 0.073 |
| Cu-DTPA | 0.727 | 0.591 | 0.263 |
| Cd-DTPA | 0.791 | 0.351 | 0.172 |
| Pb-DTPA | 0.759 | 0.622 | 0.07 |
| Ni-DTPA | 0.637 | 0.734 | 0.094 |
| Total Zn | 0.979 | 0.587 | 0.072 |
| Total Cu | 0.813 | 0.548 | 0.135 |
| Total Cd | 0.775 | 0.586 | 0.06 |
| Total Pb | 0.759 | 0.576 | − 0.193 |
| Total Ni | 0.799 | 0.525 | − 0.128 |
TDS: total data set; MDS: minimum data set; OM: organic matter; CCE: calcium carbonate equivalent; CEC: cation exchange capacity; EC: electrical conductivity; SAR: sodium adsorption ratio; ESP: exchangeable sodium percentage.
Underlined bold font values are considered highly weighted.