| RMSE | MAE | NS | r2 | |
| mg NO3·kg−1 | mg NO3·kg−1 | |||
| MLR | ||||
| Nfert + DOY + Σrain + Σtemp + depth + % Clay | 3936.10 | 3590.50 | −873 | Reference |
| MARS | ||||
| Σrain + DOY + Σtemp + Nfert | 113.27 | 76.00 | 0.28 | 1.00 |
| MLP | ||||
| Σrain + DOY + Σtemp + Nfert + %Clay | 92.03 | 64.07 | 0.52 | 1.00 |
| LS-SVM | ||||
| Σrain + DOY + Σtemp + Nfert + %Clay + depth | 78.30 | 58.16 | 0.65 | 1.00 |