Safe Utilization of High Cadmium Cropland by Random Forest Based on Soil Properties

• • Lily BCF-Cd is significantly higher than maize BCF-Cd, with lily exceeding the medicinal limit of 0.3 mg·kg−1 in many samples, whereas maize remained below food safety thresholds, indicating differential risk and necessitating crop-specific management. • • Soil pH was identified as the most critical factor controlling BCF-Cd for both crops, with feature importance analysis showing pH dominance; this underscores pH management as a primary intervention for reducing Cd uptake. • • Random forest models with hyperparameter optimization achieved optimal predictive performance for BCF-Cd, enabling accurate spatial predictions for zoning; the models incorporated soil pH, Mn, OM, and ba as key predictors. • • The proposed zoning scheme, based on model predictions, balances economic benefits (lily has 5–10 times higher value per mu than maize) with safety, offering a practical framework for high-Cd cropland management.