Principal component scores based on 32 variableszyx. Data from 84 plots in western suburban Chicago, IL.
| Principal component | |||||
|---|---|---|---|---|---|
| PC1 | PC2 | PC3 | PC4 | PC5 | |
| Eigenvalue | 8.23 | 5.10 | 3.26 | 2.40 | 2.53 |
| Proportion | 25.71 | 15.93 | 10.19 | 7.49 | 6.04 |
| Cumulative proportion | 25.71 | 41.64 | 51.83 | 59.32 | 65.36 |
| Scores of five rotated eigenvectors | |||||
| SOM (%) | 0.90y | −0.27 | 0.25 | 0.12 | −0.09 |
| N (%) | 0.89y | −0.34 | 0.22 | 0.05 | −0.07 |
| C (%) | 0.80y | 0.22 | 0.15 | −0.09 | 0.18 |
| Fine POM (g kg−1) | 0.74y | −0.08 | −0.07 | 0.40 | 0.21 |
| Total POM (g kg−1) | 0.70y | 0.00 | −0.12 | 0.40 | 0.15 |
| K (mg kg−1) | 0.55y | −0.27 | 0.42 | 0.10 | 0.07 |
| WAS (%) | 0.53y | −0.33 | 0.01 | −0.02 | −0.33 |
| DON (mg kg−1) | 0.46 | −0.22 | −0.14 | −0.09 | 0.20 |
| Mg (mg kg−1) | 0.42 | 0.37 | 0.15 | 0.34 | −0.20 |
| Root restriction depth (cm) | 0.37 | −0.37 | 0.59y | −0.19 | −0.19 |
| Structure type | 0.36 | −0.04 | 0.49 | 0.22 | −0.02 |
| MBN (mg kg−1) | 0.35 | 0.15 | 0.12 | 0.77y | 0.00 |
| Silt (%) | 0.29 | −0.39 | −0.01 | 0.66y | 0.32 |
| Nmin. (mg NH4+ and NO3− kg−1 d−1) | 0.24 | −0.15 | −0.25 | 0.24 | 0.44 |
| eCEC (cmol(+) kg−1) | 0.22 | 0.82y | 0.28 | 0.14 | −0.16 |
| GSM (%) + | 0.12 | 0.02 | −0.83y | 0.18 | −0.28 |
| NH4+ (mg kg−1) | 0.11 | 0.43 | −0.44 | 0.14 | −0.22 |
| Sand (%) | 0.09 | −0.18 | −0.25 | −0.54y | 0.06 |
| RES (mg CO2 kg−1 d−1) | 0.08 | 0.06 | −0.06 | 0.16 | 0.82y |
| Ca (mg kg−1) | −0.01 | 0.84y | 0.23 | −0.19 | 0.00 |
| VF/F roots (# cm−2) | −0.05 | 0.16 | −0.01 | −0.24 | −0.04 |
| qCO2 | −0.05 | −0.02 | −0.12 | −0.24 | −0.79y |
| PR (kPa) | −0.07 | −0.06 | −0.87y | −0.06 | −0.07 |
| MBC/TOC | −0.17 | 0.00 | 0.01 | 0.87y | −0.09 |
| Chroma | −0.25 | −0.35 | −0.47 | −0.06 | 0.15 |
| EC (dS m−1) | −0.31 | 0.72y | −0.13 | 0.04 | 0.01 |
| Clay (%) | −0.33 | 0.49 | 0.10 | −0.50y | −0.36 |
| VWC (%) | −0.37 | 0.36 | −0.71y | 0.09 | −0.21 |
| C/N | −0.44 | 0.63y | −0.10 | −0.25 | 0.26 |
| pH | −0.45 | 0.83y | −0.02 | 0.01 | 0.06 |
| Value | −0.47 | −0.10 | −0.36 | 0.13 | 0.20 |
| ρb (Mg m−3) | −0.55y | 0.12 | −0.39 | −0.16 | −0.38 |
↵zOnly principal components with eigenvalues >1 and that explain >5% of the total variance were retained.
↵yParameters with significant loadings on the within column principal component.
↵xWet-aggregate stability (WAS), dissolved organic N (DON), microbial biomass N (MBN), N mineralization (Nmin), microbial respiration (RES), bulk density (ρb), electrical conductivity (EC), calcium (Ca), magnesium (Mg), potassium (K), effective cation exchange capacity (eCEC), gravimetric soil moisture (GSM), ammonia (NH4+), nitrogen (N), carbon (C), soil organic matter (SOM), particulate organic matter (POM), metabolic quotient (qCO2) in 10−3 (mg CO2 kg−1 d−1 / mg MBC g−1), penetration resistance (PR), microbial biomass C / total organic C (MBC/TOC) in 10−2, very fine and fine roots (VF/F).