Escape of Elemental Phosphorus from Soil when Applied as White Phosphorus or the Phosphorus‐Sulfur Eutectic Solution

Abstract When molten white phosphorus was applied to soil and not adequately covered, oxides of P issued from the soil surface. The escape of P from soil fertilized with pellets of white phosphorus or the eutectic solution of P4‐S8 was determined. Most of the P recovered from the atmosphere was P4 rather than oxides, furthermore, P4 escape was considerably greater from phosphorus applied as the P4‐S8 eutectic solution than from pellets of white phosphorus. The escape of P4 from the eutectic solution also persisted longer than from a like application of white phosphorus. No appreciable difference was found in phosphorus escape from a calcareous soil as compared to that from an acid soil. Phosphorus escape was reduced by deeper placement, but was not prevented by placement at a depth of 10 cm or by increased soil moisture levels up to field capacity. Phosphorus sulfides applied to soil did not release phosphorus as did the eutectic solution of P4‐S8. Calculations suggest that hazardous levels of P4 might accumulate in the air above fields fertilized with the P4‐S8 eutectic solution.