Soil-Plant Nutrient Dynamics and Edaphic Constraints of Cashew Genotypes in the Amazon Savanna

To guide sustainable cashew cultivation, this study evaluated the nutritional dynamics and environmental interactions of five cashew clones across two contrasting pedological environments (clay-rich vs highly sandy) acting as extreme case studies within the Amazon Savanna (Roraima). By analyzing soil profiles (0–40 cm) and foliar nutrient concentrations, we identified extreme spatial heterogeneity. In the clay-rich soils of Normandia, severe acidity and high exchangeable aluminum were observed, alongside higher soil organic matter (SOM) and significantly greater foliar K accumulation across all clones, while N and P increases were genotype-specific. Conversely, the highly sandy soils (>80% sand) of Bonfim exhibited characteristics associated with nutrient leaching risks. Principal Component Analysis explained 81.6% of the data set’s total variance (PC1:69.3%; PC2:12.3%), revealing an absolute clustering of samples by cultivation environment rather than by genotype. This suggests that local edaphic conditions strongly shape the crop’s nutritional signature. We hypothesize that SOM acts as a key buffer in these environments, potentially mitigating Al stress and reducing nutrient loss. Clone BRS 274 demonstrated stable nutritional performance in Normandia, while clone CCP 09 exhibited physiological responses adapted to the sandy soils of Bonfim.