🤖 AI Summary
To address the need for precise crop phenological monitoring, this study proposes an end-to-end machine learning framework integrating time-series Sentinel-1 (SAR), Sentinel-2 (optical) remote sensing, and high-resolution climate data. Methodologically, it innovatively couples radar backscatter, red-edge vegetation indices, and dynamic temperature/precipitation features, employing a spatiotemporally adaptive weighted fusion mechanism to mitigate cloud/rain interference and regional phenological heterogeneity. Multi-source temporal alignment, sliding-window phenophase encoding, and joint preprocessing are introduced, with ensemble modeling via XGBoost and Random Forest. Validated across three major European agricultural regions, the framework achieves mean absolute errors ≤5.2 days for emergence, flowering, and maturity estimation—37% lower than single-source baselines—and attains an F1-score of 0.89. It enables sub-meter-scale field-level phenological mapping and supports crop model calibration.