Wikipedia

Diferencia entre revisiones de «Suelo sulfatado ácido»

Explorar historial interactivamente
← Ir a diferencia anteriorIr a siguiente diferencia →
Contenido eliminado Contenido añadido
VisualWikitexto
nuevo contenido
Línea 1:
{{en desarrollo}}
 
Los '''Suelos sulfatados ácidos''' son suelos que existen en la naturaleza, sedimentos o substratos orgánicos (por ejemplo [[turba]]) que se forman bajo condiciones de inundación. Estos suelos contienen minerales de [[sulfuros de hierro]] (predominantemente del mineral [[pirita]]) o sus productos [[Redox|de oxidación]]. En estado no alterado por debajo de la [[tabla de agua]], los suelos sulfatados ácidos son benignos. Sin embargo, si los suelos se drenan, se excavan o se exponen al aire por desplazamiento hacia abajo de la tabla de agua, los sulfuros reaccionarán con el [[oxígeno]] para formar [[ácido sulfúrico]]<ref name="DEC June 06">Identification & Investigation of Acid Sulfate Soils (2006), Department of Environment, Western Australia. Tomado de [http://portal.environment.wa.gov.au/portal/page?_pageid=53,84383&_dad=portal&_schema=PORTAL portal]</ref>.
La liberación de ácido sulfúrico del suelo puede a su vez liberar [[hierro]], [[aluminio]], y otros [[metales pesados]] (particularmente [[arsénico]]) en el suelo. Una vez movilizados de esta forma, el ácido y los metales pueden crear una gran variedad de impactos adversos: muerte de la vegetación, filtración en el agua subterránea con posterior acidificación de la misma y de otros cuerpos de agua, muerte de [[peces]] y de otros organismos acuáticos, y degradación de las estructuras de [[hormigón]] y [[acero]] hasta el punto de provocarles un fallo estructural.<ref name="DEC June 06" />.
 
<!--▼
== Acid sulfate soil formation ==
[[Image:BissauPolders.jpg|thumb|300px|Polders with acid sulfate soils in Guinea Bissau along a sea-arm amidst mangroves]]▼
The soils and sediments which are most prone to becoming acid sulfate soils are those which formed within the last 10,000 years, after the last major [[sea level rise]]. When the sea level rose and inundated the land, sulfate in the seawater mixed with land sediments containing iron oxides and organic matter<ref name="DEC June 06" />. Under these [[Hypoxia (environmental)|anaerobic]] conditions, [[lithotrophic]] bacteria such as ''Desulforvibrio desulfuricans'' form iron sulfides ([[pyrite]])<ref name="DEC June 06" />. Up to a point, warmer temperatures are more favourable conditions for these bacteria, creating a greater potential for formation of iron sulfides. Tropical waterlogged environments, such as [[mangrove]] swamps or estuaries, may contrain higher levels of pyrite than those formed in more temperate climates.<ref name="CSIRO Technical Manual">Acid Sulfate Soil Technical Manual 1.2 (2003), CSIRO Land & Water, Australia. Retrieved from [http://www.clw.csiro.au/staff/FitzpatrickR/barker_inlet_reports/Final_App1_coastal_ASS_tech_manual_v1.2.pdf CSIRO]</ref>
 
== Formación de suelos sulfatados ácidos ==
The pyrite is stable until it is exposed to air, at which point the pyrite oxidises and produces sulfuric acid. The impacts of acid sulfate soil leachate may persist over a long time, and/or peak seasonally (after dry periods with the first rains). In some areas of Australia, acid sulfate soils that drained 100 years ago are still releasing acid.<ref name="Sammut Lines-Kelly">Sammut, J & Lines-Kelley, R. (2000) Acid Sulfate Soils 2nd edition, Environment Australia, ISBN 0-7347-1208-1. Retrieved from [http://www.environment.gov.au/coasts/cass/booklet.html booklet]</ref>▼
▲[[Image:BissauPolders.jpg|thumb|300px|Polders[[Pólder]]es withcon acidsuelos sulfatesulfatados soilsácidos in [[Guinea Bissau along]] a sea-armlolargo de un brazo de mar amidstentre mangrovesmanglares.]]
Los suelos y sedimentos más propensos a convertirse en suelos sulfatados ácidos son aquellos formados en los últimos 10,000 años, después del último [[aumento del nivel del mar]] importante. Cuando el nivel del mar subió e inundó la tierra, los [[ión sulfato|sulfatos]] del agua del mar se mezclaron con los sedimentos que contenían [[óxidos de hierro]] y [[materia orgánica]] <ref name="DEC June 06" />. Bajo estas condiciones [[Hipoxia (ambiental)|anaeróbicas]], las bacteria [[litotrofo|litotróficas]] tales como ''Desulforvibrio desulfuricans'' forman sulfuros de hierro ([[pyrite]])<ref name="DEC June 06" />. Hasta cierto punto, las temperaturas más cálidas ofrecen condiciones más favorables para estas bacterias, creando un mayor potencial para la formacion de sulfuros de hierro. Los hábitats inundados tropicales, como [[manglar]]es, marismas o estuarios, puede producir niveles más altos de pirita que los que se forman en climas más templados.<ref name="CSIRO Technical Manual">Acid Sulfate Soil Technical Manual 1.2 (2003), CSIRO Land & Water, Australia. Retrieved from [http://www.clw.csiro.au/staff/FitzpatrickR/barker_inlet_reports/Final_App1_coastal_ASS_tech_manual_v1.2.pdf CSIRO]</ref>
 
▲TheLa pyritepirita ises stableestable untilhasta itque isse exposedexpone toal airaire, aten whichcuyo pointmomento thela pyritepirita oxidisesse andoxida producesy sulfuricproduce acidácido sulfúrico. TheLos impactsimpactos ofen acidel sulfate[[lixiviado]] soilde leachatelos maysuelos persistsulfatados overácidos apueden longpersistir timeun largo tiempo, andy/oro peakelevarse seasonallyestacionalmente (aftercon drylas periodsprimeras withlluvias thedespués firstde rainsperíodos secos). InEn somealgunas areasáreas ofde Australia, acidlos sulfatesuelos soilssulfatados thatácidos drainedque 100fueron yearsdrenados hace 100 agoaños aretodavía stillestán releasingliberando acidácido.<ref name="Sammut Lines-Kelly">Sammut, J & Lines-Kelley, R. (2000) Acid Sulfate Soils 2nd edition, Environment Australia, ISBN 0-7347-1208-1. Retrieved from [http://www.environment.gov.au/coasts/cass/booklet.html booklet]</ref>
▲<!--
===Chemical reaction===
When drained, pyrite (FeS<sub>2</sub>) containing soils (also called cat-clays) may become extremely acidic ([[pH]] < 4) due to the oxidation of pyrite into sulfuric acid (H<sub>2</sub>SO<sub>4</sub>). In its simplest form, this [[chemical reaction]] is as follows:
Línea 26 ⟶ 28:
 
The iron can be present in [[bivalent (chemistry)|bivalent]] and [[trivalent]] forms (Fe<sup>++</sup>, the ferro ion, and Fe<sup>+++</sup>, the ferri ion respect­ively). The ferro form is [[soluble]], whereas the ferri form is not. The more oxidized the soil becomes, the more the ferri forms will dominate.
Acidsuelos sulfatesulfatados soilsácidos exhibit an array of colors ranging from black, brown, blue-gray, red, orange and yellow.
The hydrogen clay can be improved by admitting sea water: the hydrogen [[adsorption|adsorbed]] will be replaced by the [[magnesium]] (Mg) and [[sodium]] (Na) present in the sea water.
 
===Geographical distribution===
Acidsuelos sulfatesulfatados soilsácidos are widespread around coastal regions, and are also locally associated with freshwater wetlands and [[saline water|saline]] sulfate-rich groundwater in some agricultural areas. In Australia, coastal acidsuelos sulfatesulfatados soilsácidos occupy an estimated 80,000&nbsp;km<sup>2</sup>, underlying coastal estuaries and floodplains near where the majority of the Australian population lives <ref>Fitzpatrick R. W., Davies P.G., Thomas B. P., Merry R. H., Fotheringham D. G and Hicks W. S. (2002). Properties and distribution of South Australian coastal acid sulfate soils and their environmental hazards. 5th International Acid Sulfate Soils Conference, Tweed Heads, NSW</ref>. Acidsuelos sulfatesulfatados soilácidos disturbance is often associated with dredging, excavation dewatering activities during canal, housing and marina developments.
 
Acidsuelos sulfatesulfatados soilsácidos which have not been disturbed are known as potential acid sulfate soils (PASS); acid sulfate soils which have been disturbed are known as actual acid sulfate soils (AASS).<ref name="CSIRO Technical Manual" />
 
== Impacts of acidsuelos sulfatesulfatados soilácidos ==
Disturbing potential acidsuelos sulfatesulfatados soilsácidos can have a destructive effect on plant and fish life, and on coastal ecosystems. Flushing of acidic leachate to groundwater and surface waters can cause a number of impacts, including:
* Ecological damage to aquatic and [[riparian]] ecosystems through fish kills, increased fish disease outbreaks, dominance of acid-tolerant species, precipitation of iron, etc.
* Effects on [[Estuary|estuarine]] fisheries and [[aquaculture]] projects (increased disease, loss of spawning area, etc).
Línea 44 ⟶ 46:
 
===Agricultural impacts===
[[Image:SeawaterInlet.jpg|thumb|300px|Sea water is admitted to a bunded polder on acidsuelos sulfatesulfatados soilácidos for soil improvement and weed control, Guinea Bissau]]
Potentiallysuelos acidsulfatados sulfatePotentially soilsácidos (also called cat-clays) are often not cultivated or, if they are, planted under [[rice]], so that the soil can be kept wet preventing oxi­dation. Subsurface [[drainage]] of these soils is normally not advisable.
 
When cultivated, acidsuelos sulfatesulfatados soilsácidos cannot be kept wet continuously because of climatic dry spells and shortages of [[irrigation]] water, sur­face drainage may help to remove the acidic and toxic chemi­cals (formed in the dry spells) during rainy periods. In the long run surface drainage can help to reclaim acidsuelos sulfatesulfatados soilsácidos <ref> ''Rice Polders Reclamation Project, Guinea Bissau''. In: Annual Report 1980, p. 26–32, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. Download from web page [http://www.waterlog.info/annrep.htm] , under nr. 12, or directly as PDF : [http://www.waterlog.info/pdf/bolanhas.pdf] </ref> . The indigenous population of [[Guinea Bissau]] has thus managed to develop the soils, but it has taken them many years of careful management and toil.
 
In an article on cautious land drainage <ref> ''Agricultural Land Drainage: A wider application through caution and restraint''. In: Annual Report 1991, p.21–35, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. Download from web page : [http://www.waterlog.info/annrep.htm] , under nr. 3, or directly as PDF : [http://www.waterlog.info/pdf/caution.pdf] </ref> , the author describes the successful application of subsurface drainage in acidsuelos sulfatesulfatados soilsácidos in coastal polders of Kerala state, India.
 
Also in the [[Sunderbans]], West Bengal, India, acidsuelos sulfatesulfatados soilsácidos have been taken in agricultural use <ref> H.S. Sen and R.J. Oosterbaan, 1993. ''Research on Water Management and Control in the Sunderbans, India''. In: Annual Report 1992, p. 8-26. International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. Download from web page : [http://www.waterlog.info/annrep.htm] , under nr. 2, or directly as PDF : [http://www.waterlog.info/pdf/sunderbans.pdf] </ref>
 
A study in South [[Kalimantan]], Indonesia, in a perhumid climate, has shown that the acidsuelos sulfatesulfatados soilsácidos with a widely spaced subsurface drainage system have yielded promising results for the cultivation of upland (sic!) [[rice]], [[peanut]] and [[soybean]]. <ref> ''Review of water management aspects in Pulau Petak'' (near the town of Bandjermasin, Kalimantan, Indonesia). Mission Report 39, Research Project on Acid Sulphate (Sulfate) Soils in the Humid Tropics. International Institute of Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands. Download from web page : [http://www.waterlog.info/reports.htm] , under nr. 7, or directly as PDF : [http://www.waterlog.info/pdf/pulaupetak.pdf] </ref> . The local population, of old, had already settled in this area and were able to produce a variety of crops (including tree fruits), using hand-dug drains running from the river into the land until reaching the back swamps. The crop yields were modest, but provided enough income to make a decent living.
 
Reclaimed acidsuelos sulfatesulfatados soilsácidos have a well developed [[soil structure]], they are well permeable, but infertile due to the [[Leaching (pedology)|leaching]] that has occurred.
 
In the second half of the 20th century, in many parts of the world, [[waterlogged]] and potentiallysuelos acidsulfatados sulfatepotentially soilsácidos have been drained aggressively to make them productive for [[agriculture]]. The results were disastrous <ref name="dent" /> . The soils are unproductive, the lands look barren and the water is very clear, devoid of silt and life. The soils can be colorful, though.
 
==Acidsuelos sulfatesulfatados soilácidos restoration==
By raising the water table, after damage has been inflicted due to over-intensive drainage, the soils can be restored.
The following table gives an example.
 
''Drainage and yield of Malaysian oil palm on acidsuelos sulfatesulfatados soilsácidos (after Toh Peng Yin and Poon Yew Chin, 1982)''<br>
''Yield in tons of fresh fruit per ha:''
{| class="wikitable"
Obtenido de «https://es.wikipedia.org/wiki/Suelo_sulfatado_ácido»