Superphosphate

From Wikipedia, the free encyclopedia
(Redirected from Super phosphate)

Superphosphate is a chemical fertiliser first discovered in the 1840s and made by reacting phosphate contains rocks with sulphuric acid. Phosphate I solution is an essential nutrient for all plants and the availability of superphosphate revolutionised agricultural productivity.

Triple superphosphate[edit]

Triple superphosphate is on of the formulations sold and is a component of fertilizer that primarily consists of monocalcium phosphate, Ca(H2PO4)2. It is obtained by treating phosphate rock with phosphoric acid. Traditional routes for extraction of phosphate rock use sulfuric acid to produce single superphosphate, an approximate 1:1 mixture of Ca(H2PO4)2 and CaSO4. Double superphosphate refers to some average of triple- and single superphosphate, resulting from the extraction of phosphate rock with a mixture of phosphoric and sulfuric acids.[1]

Many fertilizers are derived from triple superphosphate, e.g. by blending with ammonium sulfate and potassium chloride. Typical fertilizer-grade triple superphosphate contains 45% P2O5eq, single superphosphate 20% P2O5eq.[1]

History[edit]

In 1842 the Rev Hounslow found coprolites in the cliffs of south Suffolk in England. He was aware from previous reasearch iin Dorset by William Buckland that coprolites were rich in phosphate which could be made available for plants by dissolution in sulphuric acid. John Bennet Lawes, who farmed in Hertfordshire learnt of these discoveries and conducted his own research and coined the product that he made as "super phosphate of lime". He patented the discovery and in 1842 started producing the material on an industrial scale which was the first chemical manure produced in the world. [2]

Edward Packard, realising the significance of this, converted a mill in Ipswich to produce this new fertilizer. He moved his operation in the 1850s to Bramford next to a similar factory that had spriung oup operated by Mt Fisons. Yhese operations were subsequently destined to form part of the Fison fertilizer company. The street where the original mill stood is still called Coprolite Street.[3]

Agricultural significance[edit]

All plants, and all animals, need phosphorous to carry out their mormal metabolism even though in the case of plants it may constitute as little as 2% of their dry matter[4]. The phosphorous can be in the form of souble phospates or organic compounds containg phosphorous. In the living cell, energy is accummulated or expended using a complex range of biochemical processes which involve the transformation of adenosine triphosphate to adenosine diphosphate when energy is being expended and the reverse when energy is being accummulated as in photosynthesis. [5]

The fate of phosphates in soil is complex as they readily form complexes with other minerals such as clays[4] and may be generally unavailable to plants except by weathering and through the action of bacterial and the soil microbiome.<re name="Soil"/> Phosphates are also lost to the soil and plant environment when cops are harvested and consumed by animals or otherwise lost to the local system.

Although there is some replenishment of spoil phosphorous from mineral sources and release from soil complexes, the rate of re-solubilisation is too low to support modern agricultural productivity. Organic phosphorous contained within plant or animal matter is much more readily re-solubilised as the material decomposes through microbial action [4]The addition of phophoorous as super-phosphate enabled much greater crop yields.

References[edit]

  1. ^ a b Kongshaug, Gunnar; Brentnall, Bernard A.; Chaney, Keith; Gregersen, Jan-Helge; Stokka, Per; Persson, Bjørn; Kolmeijer, Nick W.; Conradsen, Arne; Legard (2014). "Phosphate Fertilizers". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 1–49. doi:10.1002/14356007.a19_421.pub2. ISBN 978-3527306732.
  2. ^ O'Connor, Bernard (2005). "The Origins and Developments of the British Coprolite industry" (PDF). Mining History:The Bulletin of the Peak Distict Historical Society. 14 (5). Retrieved 27 March 2024.
  3. ^ "The Story of Corpolite Street". Ipswich Maritime Trust. 26 October 2019. Retrieved 28 March 2024.
  4. ^ a b c "Phosphorus Basics: Understanding Phosphorus Forms and Their Cycling in the Soil". Alabama A&M and Auburn Universities. 19 April 2019. Retrieved 28 March 2024.
  5. ^ "Why Phosphorous is important". New South Wales Departmet of Primary Industries. Retrieved 28 March 2024.