Soil properties affecting phosphorus extraction from Portuguese soils by conventional and innovative methods

Abstract The conventional Bray 1, Egner‐Riehm, Olsen, and the innovative cation/ anion exchange resin membranes (CAERM) and iron oxide‐impregnated filter paper strips (Pi) procedures were compared as phosphorus (P) extradants from 73 represintative Portuguese soils. The soils were characterized by wide variability of their pedological, physical, and chemical properties. Eleven FAO‐UNESCO soil units, with prevailing Anthrosol, Calcisol, Cambisol, Fluvisol, Leptosol, Luvisol, and 10 different textural classes, with prevailing loamy sand, sandy loam, loam, silty loam, clay loam, silty clay loam, were recognized. The soils showed the following properties: CaCO3 0.0–50.9 g100 g‐1, organic matter 0.4–8.4 g 100 g‐1, pH‐CaCl2 3.9 to 7.9, cation exchange capacity 1.5–57.6 cmolc kg‐1 Soil‐P (mg kg‐1) ranges were: 0.2–185.9 for Bray 1, 0.6–307.7 for Egner‐Riehm, 1.0–100.5 for Olsen, 1.1–69.4 for Pi, and 0.4–48.8 for CAERM. The P extraction efficiency decreased along with the order Bray 1 > Egner‐Riehm > Olsen > Pi >...