Appendix 4.
Stepwise non-linear multiple regression models of soil respiration rate on edaphic variables.
| Models | Variables | Multiple Regression Model | R 2 | RMSE | AIC | %Bias |
|---|---|---|---|---|---|---|
| Linear | OM |
|
0.152 | 11.17 | 212.93 | 0.00 |
| Linear | OM, pH |
|
0.339 | 9.66 | 207.09 | 0.00 |
| Linear | OM, pH, Silt |
|
0.408 | 8.95 | 204.96 | 0.00 |
| Linear | OM, pH, Silt, SM |
|
0.403 | 8.79 | 205.99 | 0.00 |
| Logarithmic | OM |
|
0.144 | 11.44 | 214.25 | 0.00 |
| Logarithmic | OM, pH |
|
0.377 | 9.76 | 207.67 | 0.00 |
| Logarithmic | OM, pH, Silt |
|
0.509 | 8.66 | 203.21 | 0.00 |
| Logarithmic | OM, pH, Silt, SM |
|
0.530 | 8.48 | 204.05 | 0.00 |
| Exponential | OM |
|
0.195 | 11.10 | 212.58 | -0.03 |
| Exponential | OM, pH |
|
0.358 | 9.91 | 208.48 | 0.07 |
| Exponential | OM, pH, Silt |
|
0.473 | 8.98 | 205.14 | 0.01 |
| Exponential | OM, pH, Silt, SM |
|
0.495 | 8.79 | 206.01 | 0.01 |
| Mixed | OM |
|
0.20 | 11.10 | 58.60 | 0.03 |
| Mixed | OM, pH |
|
0.39 | 9.69 | 57.77 | -0.04 |
| Mixed | OM, pH, Silt |
 |
0.56 | 8.24 | 56.50 | 0.03 |
| Mixed | OM, pH, Silt, SM |
 |
0.58 | 8.03 | 58.69 | 0.00 |