Model | Predictor variable(s) | AUC | AIC |

A | Fluvisols (probability) | 0.69 | 787 ± 5 |

B | Irrigated area | 0.72 | 739 ± 7 |

C | Aridity, slope (binary, 0.1°) | 0.73 | 716 ± 8 |

D | Slope (binary, 0.1°), soil pH | 0.77 | 688 ± 9 |

E | Aridity, Holocene fluvial sediments (binary), slope (binary, 0.1°) | 0.77 | 664 ± 8 |

F | Fluvisols (probability), Holocene fluvial sediments (binary), soil organic carbon, soil pH, slope (binary, 0.1°) | 0.80 | 644 ± 9 |