[1] So valuable were these resources during the Industrial Revolution that graveyards and catacombs across Europe were pillaged for human bones to satisfy demand.
[1] In 1842, the Reverend John Stevens Henslow found coprolites – fossilised dinosaur dung – in the cliffs of south Suffolk in England.
He was aware of previous research in Dorset by William Buckland which showed that coprolites were rich in phosphate that could be made available for plants by dissolution in sulfuric acid.
[1] Edward Packard, recognising the significance of Lawes' work, converted a mill in Ipswich to produce this new fertiliser from coprolites excavated in the village of Kirton.
The lower price contributes to its widespread adoption, particularly in developing regions where the costs of agricultural inputs are a significant consideration.
[12] All formulations of superphosphate contain a significant proportion of soluble and available phosphate ions which is the key quality that has made them essential for modern agriculture.
[7] Single superphosphate is produced using the traditional method of extraction of phosphate rock with sulfuric acid, an approximate 1:1 mixture of Ca(H2PO4)2 and CaSO4.
[16] While superphosphate enriches soil with phosphorus, excessive or imbalanced application can disrupt nutrient ratios, leading to deficiencies or toxicities in plants.
Many terrestrial orchids which rely on mycorrhizal associations may have similar sensitivities to elevated phosphate levels[22] and populations may be suppressed by applications of superphosphate containing fertiliser.
However, teasing out the contribution made to this problem by the use of superphosphate is difficult because of the wide range of other sources of phosphorus compounds in both human and animal waste streams.
Recent issues on the River Wye have been traced back to intensive poultry rearing with the excess phosphate coming from poorly-managed chicken manure.