- Soil acidification
Soil acidification is the buildup of
hydrogen cation s, also calledproton s, in thesoil . This happens when a proton donor is added to the soil. The donor can be anacid , such asnitric acid andsulfuric acid (these acids are common components ofacid rain ). It can also be a compound such asaluminium sulfate , which reacts in the soil to release protons. Manynitrogen compounds, which are added asfertilizer , also acidify soil over the long term because they produce theammonium ion which is a proton donor.Acidification also occurs when base cations such as
calcium ,magnesium ,potassium andsodium are lost from the soil. Losses occur when these bases are leached from the soil. This leaching increases with increasing precipitation.Acid rain accelerates theleaching of bases. Plants take bases from the soil as they grow, donating a proton in exchange for each base cation. Where plant material is removed, as when a forest is logged or crops are harvested, the bases they have taken up are permanently lost from the soil.Many plants produce organic acids. Where plant litter accumulates on or is incorporated to the soil, these acids (including
acetic acid ,humic acid (see http://www.suprahumic.unina.it/),oxalic acid , andtannic acid ) are liberated. This is especially acute in soils underconiferous trees such aspine ,spruce andfir , which return fewer base cations to the soil than do mostdeciduous trees . Certain parent materials also contribute to soil acidification.Granite s and their alliedigneous rocks are called "acidic" because they have a lot of freequartz , which producessilicic acid on weathering. Also, they have relatively low amounts of calcium and magnesium. Somesedimentary rocks such asshale andcoal are rich insulfide s, which, when hydrated and oxidized, produce sulfuric acid which is much stronger than silicic acid. Many coal spoils are too acidic to support vigorous plant growth, and coal gives off strong precursors to acid rain when it is burned. Marineclay s are also sulfide-rich in many cases, and such clays become very acidic if they are drained to an oxidizing state.ome chemicals which acidify the soil
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Aluminium sulfate
*Ammonia
*Ammonium nitrate
*Ammonium phosphate
*Ammonium sulfate
*Ferrous sulfate
*Monopotassium phosphate
*Phosphoric acid
*Urea
*Urea phosphate ee also
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Acid sulfate soil
*Soil pH
*Soil salination References
* [http://www.dpi.vic.gov.au/dpi/nrenfa.nsf/childdocs/-80E62E2EAB672EE24A256B520005A0AF-7C866D87F6E182014A256B52000B09C0?open Soil acidification]
* [http://www.treesearch.fs.fed.us/pubs/13802 Fenn, M. E.; Huntington, T. G.; McLaughlin, S. B.; Eagar, C.; Gomez, A.; Cook, R. B. 2006. Status of soil acidification in North America Journal of Forest Science 52:3-13.]
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