Establishment of standards for the nutritional balance of dwarf cashew based on the CND method

The Compositional Nutrient Diagnosis (CND) is a diagnostic tool designed to identify nutritional imbalances in plants and, when combined with soil analysis, supports more accurate fertilizer recommendations. This study aimed to apply CND standards to assess the nutritional status of dwarf cashew trees cultivated under rainfed conditions in Brazil. Leaf samples (fifth and sixth mature leaves from fruiting shoots at the onset of flowering) were collected and analyzed for macro- and micronutrients as well as sodium concentrations. From a database of 248 samples, 33 outliers were excluded using Mahalanobis distance. The mean cashew nut yield of 1,485 kg ha−1 was used to define the high-yield subpopulation (48% of the orchards). Based on this subpopulation, critical levels and sufficiency ranges for nutrients and sodium were established, enabling the evaluation of plant nutritional status and providing a basis for refining fertilizer recommendations for dwarf cashew.