acid sulphate soils - Community Over Mining

It is also important to be able to recognise indicators of actualacid sulfate soils to prevent further acidification of land andwaterways. These indicators include the cloudy green-blue water,excessively clear water, iron stains, poor pasture, scalded soil,and yellow jarosite described earlier in this booklet.LimingSulfuric acid can be neutralised with agricultural lime, but this istoo costly for large areas of badly affected land. One techniquethat has had good results to date is liming of drains so that thesulfuric acid produced in the drain walls is neutralised by the limeas it is washed out. Acid water can also be neutralised by lime.Water cover22Re-flooding land with freshwater can halt further acidification. Itmay even reverse the acidification process if the site can be keptwet and there is sufficient organic matter. Water cover can enableacid tolerant grasses to recolonise severe acid scald areaspreventing soil erosion.However, freshwater reflooding may increase aciddischarges if acid water can sit closer to the ground surface andmore easily flow into waterways during moderate rainfall. The useof freshwater re-flooding requires caution and technical advicebefore it is applied. Seawater flushing may lead to increased acidneutralisation but may cause other impacts that have not beenfully investigated. For example, acid sulfate soils change chemicallyand physically once they are oxidised. The landscape may be ata much lower elevation due to soil shrinkage and may alsotransmit saltwater to areas previously unaffected. Research intoboth freshwater and seawater flooding of acidified lands is beinginvestigated.Landowners are advised to seek expert technicaladvice for remediation of acid sulfate soil sites.