Phytoavailable phosphorus (P₂O₅) and potassium (K₂O) in topsoil for apple orchards and vineyards, South Tyrol, Italy

Accurate fertilization management is a present-day challenge and can conciliate profitability and sustainability in agriculture production. This study presents topsoil concentrations of P₂O₅ and K₂O in apple orchards and vineyards in South Tyrol, Italy. Sixteen thousand georeferenced soil samples were collected and spatialized using ordinary local kriging. Measured average and maximum concentrations of P₂O₅ were 260 and 1500 mg/kg, respectively, in apple orchards, and 280 and 880 mg/kg, respectively, in vineyards. Similarly, measured average and maximum concentrations of K₂O were 210 and 1040 mg/kg, respectively, in apple orchards, and 250 and 820 mg/kg, respectively, in vineyards. Overall, K₂O concentration was mostly within the recommended thresholds, while P₂O₅ concentration was frequently higher than the target level for optimal production. The resulting maps (1:25,000 scale) of P₂O₅ and K₂O showed modest accuracy with RMSE of 115.7 and 78.3 mg/kg, respectively. These maps can support evidence-based decision making by multiple stakeholders.