Characterization of phosphorus fractions in mountain soils of the Bavarian Alps by ³¹P NMR spectroscopy

NaOH‐extracts from different soils of the alpine and shrub zones at the Schneibstein (Nationalpark Berchtesgaden) between 1790–2275 m were studied using 31 P NMR spectroscopy. NaOH (0.5 M) dissolved 29–49% of P t . Orthophosphate monoesters were the dominant fraction (41–79%). Orthophosphate diesters comprised 10–20%. A higher diester content (36%) was found in a hydromorphic soil. Inorganic phosphate comprised 5–27%, depending on soil pH. So, in acid horizons (pH 4.45 and 5.05) 27 and 23% were detected, whereas in horizons with higher pH (> 6) only small amounts (5–8%) were found. Pyrophosphate and polyphosphates were found in traces. Phosphonates (ca. 6%) occurred mainly in acid soils.