Spatio-Temporal Dynamics of Soil Fertility Under Miombo and Planted Forest Cover in Huambo Province, Angola

Soil fertility plays a fundamental role in agricultural productivity and ecosystem sustainability in tropical regions and is strongly influenced by vegetation cover and land-use dynamics. In Huambo Province, a major agricultural region characterised by extensive Miombo woodlands and timber plantations, understanding soil–vegetation interactions is essential for sustainable land management. This study assessed the spatial variability of soil fertility under different vegetation cover types (2017-2025) in support of SDGs 2, 13 and 15. ESA WorldCover Sentinel-2 land/cover datasets (10 m) and iSDAsoil products (30 m), including pH, organic carbon, cation exchange capacity (CEC), magnesium, phosphorus, potassium and soil texture, were integrated. Land cover and soil layers were resampled to 30 m in PyQGIS integration to ensure pixel-level compatibility. Temporal dynamics were analysed in Google Colab using modal frequency and change-detection approaches. Descriptive statistics, ANOVA and Spearman correlation analyses evaluated variability and relationships among soil attributes under different vegetation covers. Principal Component Analysis, Cluster Analysis and Moran’s I identified spatial fertility patterns and homogeneous management zones, while an Integrated Fertility Index (IFI) was generated through min–max normalisation and map algebra. Results revealed significant landscape changes, including a sharp decline in open natural forest cover from 17.3% to below 5% between 2022 and 2023, followed by partial recovery. Agricultural areas expanded to 52% in 2021, while urban areas reached 46% in 2023, reflecting increasing anthropogenic pressure. Soil attributes showed moderate variability, with pH presenting greater stability, whereas organic carbon and texture exhibited higher heterogeneity, particularly in agricultural, Miombo and planted forest areas. Strong positive correlations were identified among CEC, magnesium and potassium, while pH showed a negative relationship with phosphorus. Spatial analyses revealed a highly organised fertility pattern, with the IFI ranging from 82.23 to 87.3 and the highest fertility conditions occurring in agricultural and planted forest zones.