Table 2.
ANCOVA results to estimate the effects of maize cultivation duration and topo-sequential position on soil properties.
| TC | TN | Av-P | Ex-K | Ex-Mg | Ex-Ca | |
|---|---|---|---|---|---|---|
| Cultivation duration [D] | − 0.41** | − 0.025*** | − 0.36† | − 0.010** | − 0.05 | − 0.42* |
| Topo-sequential position | ||||||
| Lower | 0.00 | 0.000 | 0.00 | 0.000 | 0.00 | 0.00 |
| Middle [M] | − 0.13 | − 0.005 | − 1.87 | 0.002 | − 0.11 | 0.48 |
| Upper [U] | − 1.52 | − 0.133 | − 0.80 | − 0.111 | − 0.63 | − 1.64 |
| Flat [F] | − 10.86** | − 0.707** | 5.60 | − 0.307** | − 2.89 | − 9.70† |
| Interaction | ||||||
| [D] × [M] | − 0.11 | − 0.005 | 0.01 | − 0.004 | 0.04 | − 0.02 |
| [D] × [U] | − 0.08 | − 0.001 | − 0.07 | − 0.001 | 0.06 | 0.15 |
| [D] × [F] | 0.42* | 0.026* | − 0.05 |
0.012 * |
0.04 | 0.29 |
| Intercept | 29.6*** | 2.0*** | 15*** | 0.59*** | 11*** | 31*** |
| R-square | 0.30 | 0.33 | 0.17 | 0.29 | 0.09 | 0.13 |
| Adjusted R-square | 0.26 | 0.29 | 0.11 | 0.24 | 0.03 | 0.08 |
| Ex-Na | pH | Clay | silt | Sand | Gravel | |
|---|---|---|---|---|---|---|
| Cultivation duration [D] | − 0.0033 | − 0.009 | 0.17 | − 0.23 | 0.14 | − 0.09 |
| Topo-sequential position | ||||||
| Lower | 0.0000 | 0.000 | 0.00 | 0.00 | 0.00 | 0.00 |
| Middle [M] | 0.0004 | 0.079 | − 1.26 | − 3.16 | 1.74 | 2.67 |
| Upper [U] | − 0.0196 | 0.017 | − 3.89 | 0.90 | 0.89 | 2.10 |
| Flat [F] | − 0.0746 | − 0.106 | − 2.12 | − 5.02 | 18.84** | − 11.70† |
| Interaction | ||||||
| [D] × [M] | 0.0009 | − 0.002 | − 0.09 | 0.12 | − 0.05 | 0.02 |
| [D] × [U] | 0.0025 | 0.001 | − 0.04 | − 0.13 | − 0.04 | 0.21 |
| [D] × [F] | 0.0054 | 0.000 | − 0.23 | 0.01 | − 0.57† | 0.78* |
| Intercept | 0.21*** | 6.7*** | 39*** | 33*** | 20*** | 7† |
| R-square | 0.03 | 0.07 | 0.05 | 0.13 | 0.17 | 0.11 |
| Adjusted R-square | − 0.03 | 0.01 | − 0.01 | 0.07 | 0.11 | 0.06 |
†, *, **, and ***Represent statistical significance at p < 0.1, 0.05, 0.01, and 0.001, respectively.