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Saline-sodic clay minespoil materials excavated during open-cut coal mining in central Queensland, Australia, pose significant challenges for revegetation, particularly where suitable topsoil capping is not available. We examined the ability of sawdust or straw mulch amendments to ameliorate the adverse properties of these minespoils and improve the success of revegetation efforts. In laboratory studies, mulch application improved infiltration, increased soil moisture retention and reduced surface crust strength. In the field, mulches incorporated to a depth of 0.15 m at application rates of at least 20 t/ha straw or 80 t/ha sawdust were needed to mitigate against capillary rise of salts during drying cycles and support satisfactory vegetation cover. Further research is needed to determine whether improvements are maintained beyond the 4-year trial period reported here. Additional keywords: reclamation, overburden, crust formation, straw, sawdust, gypsum., Introduction Stripping operations at many open-cut coal mines in central Queensland, Australia, result in spoil (waste rock) materials of Tertiary origin being deposited on the surface. Deeply weathered Tertiary sediments [...]

Abstract: High salt levels in mine spoils have been identified as one of the major chemical limitations to plant establishment after coal mining in central Queensland. Soil solution extracts from spoils indicated that EC levels of up to 26dS/m could be encountered. Glasshouse trials examined the emergence and growth of Eucalyptus citriodora, Eucalyptus camaldulensis and Eucalyptus populnea provenances and Acacia salicina subjected to such EC levels. Relatively low levels of salt (100mM NaCl, or 11dS/m) with respect to the levels encountered on mine spoils, were enough to substantially reduce the rate and percentage emergence of all eucalypt provenances. A. salicina was found to be superior to the eucalypts in its ability to emerge and survive under saline conditions. It was the only species to have seedlings emerge and survive at 200mM NaCl (20dS/m), and the effect of salt on decreasing seedling dry weight was less pronounced for A. salicina than for any of the eucalypts. Established plants survived the range of salt treatments far better than emerging seedlings, with survival of established plants being reduced only at 300 and 400mM NaCl (28 and 36dS/m, respectively). A. salicina performed significantly better at 300 and 400mM NaCl than most of the eucalypts studied. [Copyright &y& Elsevier]

In Australia, metal-contaminated sites, including those with elevated levels of copper (Cu), are frequently revegetated with endemic plants. Little is known about the responses of Australian plants to excess Cu. Acacia holosericea , Eucalyptus crebra , Eucalyptus camaldulensis , and Melaleuca leucadendra were grown in solution culture with six Cu treatments (0.1 to 40 μ M ). While A. holosericea was the most tolerant to excess Cu, all of the species tested were sensitive to excess Cu when compared with exotic tree and agricultural species. The critical external concentrations for toxicity were -1 ( A. holosericea ), 150 μ g g -1 ( E. crebra ), 25 μ g g -1 ( E. camaldulensis ), and 165 μ g g -1 ( M. leucadendra ). These results provide the first comprehensive combination of growth responses, critical concentrations, and toxicity symptoms for three important Australian genera for use in the management of Cu-contaminated sites. [ABSTRACT FROM AUTHOR]

Focuses on seedling responses of three Australian native trees to toxic concentrations of zinc in solution culture. Exposure of the seedlings of Acacia holoserices, Eucalyptus camaldulensis and Melaleuca leucadendra to six zinc treatments; Increase in tissue zinc concentrations with increase in solution zinc; Information on root tissue and shoot tissue concentrations in solution zinc concentrations.