Growing Eremanthus erythropappus in crushed laterite: A promising alternative to topsoil for bauxite-mine revegetation.
Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas.
Department of Geology, Federal University of Ouro Preto, 35.400-000 Ouro Preto, Minas Gerais, Brazil.
Naiara Amaral de Miranda
NA
Machado
Mariangela Garcia Praça
MG
Leite
Maurílio Assis
MA
Figueiredo
Alessandra Rodrigues
AR
Kozovits
D000537:Aluminum Oxide / Q000378:metabolism; D019659:Asteraceae / Q000187:drug effects / Q000254:growth & development*; D001673:Biodegradation, Environmental; D001938:Brazil; D003247:Conservation of Natural Resources / Q000379:methods*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D011897:Random Allocation; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000378:metabolism
D012987:Soil; D012989:Soil Pollutants; D000537:Aluminum Oxide
Allometry; Canga; Eremanthus erythropappus; Iron duricrust; Particles size reduction; Relative growth; Revegetation