Superphosphate
From Wikipedia, the free encyclopedia
Superphosphate is a fertilizer produced by the action of concentrated sulfuric acid on ground phosphate rock.
- Ca3(PO4)2 + 2H2SO4 → Ca(H2PO4)2 + 2CaSO4
A large market for superphosphate was created in the second half of the 20th century by the development of aerial topdressing in New Zealand which allowed superphosphate to be spread economically over large areas.
![Limestone pinnacles left on Nauru after phosphate mining](../../../upload/shared/thumb/8/83/Karst_following_phosphate_mining_on_Nauru.jpg/180px-Karst_following_phosphate_mining_on_Nauru.jpg)
Superphosphate can be created naturally in large quantities by the action of guano, or bird feces, resulting in deposits around sea bird colonies which can be mined. The most famous mining site is the island of Nauru in the South Pacific much of the "soil" from which was mined, creating temporary wealth for the inhabitants, but destroying their environment.
Earthworms cannot coexist in fields fertilized with superphosphates. Superphosphate fertilized soils will not have the soil structure and nutrient availability improved by earthworms. Large scale superphosphate use has lead to some species of earthworm, such as the Giant Gippsland earthworm becoming threatened.