Phosphorus and Potassium Leaf Analysis in Pastures

Foliar analysis assesses phosphorus (P) and potassium (K) levels in permanent pastures to evaluate nutrient uptake and guide fertilization. It measures P and K concentrations in plant tissue (% dry matter) and soil pH, calculating indices (IP for P, IK for K) to determine plant nutritional status. Results inform management: IP >120 suggests no fertilization for 1–2 years; 100–120 indicates maintenance needs (~100 kg K₂O/ha, ~30 kg P₂O₅/ha); 60–100 requires adjustments based on IK (e.g., IK <70 needs +40–60 kg K₂O/ha); IK <60 signals severe deficiency risking animal health and legume suppression. Conducted by Normandy Agronomic Laboratory (Saint-Cloud), accredited under ISO/IEC 17025, with sample collection (100–200 g, spring) and costs available via regional agricultural services. Published 02/04/2025.