• Multi-year monitoring of sugarcane fields using Sentinel-2 satellite time series (March–November). • Object-based segmentation with extraction of spectral, textural, and morphological descriptors. • Integration of NDVI, EVI, and MSAVI indices to detect cut–regrowth events and phenological patterns. • Evaluation of temporal deep learning models (Transformer, TCN, TSMixer, GRU, and LSTM) for field-scale age inference. • Automated classification of sugarcane age into nine intervals (0–2, 3–5, … ≥ 24 months) across multiple regions. • The Transformer model achieved the best cross-region generalization, highlighting its robustness for operational sugarcane age estimation. Accurate monitoring of sugarcane growth stages and field age is essential for optimizing yield estimation and harvest logistics within the sugar–energy sector. This study proposes a temporal deep learning framework for inferring sugarcane cycle age from multitemporal Sentinel-2 imagery. The dataset comprises 30,282 object-level temporal windows extracted from major sugarcane-producing regions in Brazil over two agricultural seasons (2023–2024). Each sample corresponds to an eight-month consecutive sequence (March–October), from which spectral, textural, morphological, and phenological features were derived. Five temporal deep learning architectures—Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), Temporal Convolutional Network (TCN), Temporal Shift Mixer (TSMixer), and Transformer—were trained and optimized using the Optuna framework. A stratified window-level split was adopted to preserve class balance and prevent temporal leakage, while model evaluation emphasized spatial generalization across regions using accuracy and F1-macro metrics. Among the evaluated approaches, the Transformer achieved the highest cross-region precision (97.7%), followed by TCN (96.6%) and TSMixer (96.4%). The results indicate that attention- and convolution-based temporal architectures effectively capture crop phenological dynamics, enabling accurate, scalable, and operational estimation of sugarcane cycle age from satellite time series.
Silva et al. (Sun,) studied this question.