Balance sheet for phosphorus in the UK.

A balance sheet for the inputs, uses and outputs of phosphorus in the UK economy has been drawn up. The major import is fertilizer, amounting to about 200 kt P per year. After fertilizers, the other imports (in kt P) are in animal feeds (63), detergents (38) and human food (14). The major outputs are sewage (50), animal excreta (26) and refuse (21); soil losses are about 20 kt. The flowpaths for phosphorus through humans, animals and plants are described. The discrepancy of about 210 kt P/yr is explained by the fact that the amount of phosphorus in the soil increases each year by almost as much as the amount of fertilizer phosphorus added. In view of UK dependence on this imported resource it is suggested that priority is given to work which might eventually have some practical application in preventing or reversing the immobilization of phosphorus in the soil.