Oxidation of red phosphorus: a study of the rate of oxidation, by air, of red phosphorus in an aqueous suspension

Abstract

An investigation into the possibility of using red phosphorus as a soil fertilizer has been carried out by Rothbaum1. Conventional superphosphate fertilizers have the disadvantage that all of the phosphate is released to the soil soon after application. Much of this is fixed by the soil before the plants have a chance to absorb it as useful phosphate material. Hence the bulk of the phosphorus spread as superphosphate is not available to plants as it becomes firmly bound in the soil. Red phosphorus has been found to oxidize slowly in moist soil releasing phosphorus oxides over a period of several months. The plants should therefore be able to utilize the phosphates as they are formed, so that there is less excess phosphate available to be fixed, as unbeneficial compounds, by the soil. It is possible that a much higher percentage of the weight of phosphorus applied would be absorbed by plants if red phosphorus was spread rather than superphosphate. As it would be impracticable to distribute the red phosphorus evenly on the pastures, a carrier would have to be provided if it were to be used as a fertilizer. If a mixture of superphosphate and about 5% of red phosphorus was spread, the superphosphate would produce the plants' initial phosphate requirements, while the red phosphorus would furnish a long term phosphate supply. Thus more efficient use of phosphorus could be achieved over longer periods of time than with the superphosphate in present use.