Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high e...Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.展开更多
The processes involved in the major steps of successful revegetation of bauxite residues are examined.The first phase is the natural physical,chemical and microbial ripening of the profile.This involves allowing the p...The processes involved in the major steps of successful revegetation of bauxite residues are examined.The first phase is the natural physical,chemical and microbial ripening of the profile.This involves allowing the profile to drain,dry,shrink and crack to depth,leaching of soluble salts,alkalinity and Na down out of the surface layers,acidification by direct carbonation and natural seeding of tolerant vegetation with an accumulation of organic matter near the surface and an attendant development of an active microbial community.Following ripening,the surface layer can be tilled and gypsum and organic matter(e.g.manures,composts,biosolids)incorporated.These amendments result in a further decrease in pH,increase in Ca and other exchangeable cations,increased leaching of Na(with a reduction in exchangeable Na and ESP),improved physical properties,particularly aggregation,and a large increase in microbial activity.Other important considerations include the choice of suitable plant species tolerant to salinity/sodicity and local environmental conditions and the addition of balanced fertilizer applications.展开更多
The adsorption of methylene blue (MB) on three soil amendments,red mud from Hungary, rd mud from UK and beringite from Belgium, wasstudied to determine the surface areas of the amendments using a0.005 mol L^-1 NaCl so...The adsorption of methylene blue (MB) on three soil amendments,red mud from Hungary, rd mud from UK and beringite from Belgium, wasstudied to determine the surface areas of the amendments using a0.005 mol L^-1 NaCl solution and deionised water as backgroundsolutions. The surface areas determined by the methylene blue methodin the 0.005 mol L^-1 NaCl solution were 3.357, 2.340 and 5.576 m^2g^-1 for red mud (Hungary), red mud (UK) and beringite, respectively,slightly lower than those in the deionised water system.展开更多
基金Projects(41877551,41842020)supported by the National Natural Science Foundation of ChinaProject supported by the Science Foundation Ireland 17/CDA/4778
文摘Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.
文摘The processes involved in the major steps of successful revegetation of bauxite residues are examined.The first phase is the natural physical,chemical and microbial ripening of the profile.This involves allowing the profile to drain,dry,shrink and crack to depth,leaching of soluble salts,alkalinity and Na down out of the surface layers,acidification by direct carbonation and natural seeding of tolerant vegetation with an accumulation of organic matter near the surface and an attendant development of an active microbial community.Following ripening,the surface layer can be tilled and gypsum and organic matter(e.g.manures,composts,biosolids)incorporated.These amendments result in a further decrease in pH,increase in Ca and other exchangeable cations,increased leaching of Na(with a reduction in exchangeable Na and ESP),improved physical properties,particularly aggregation,and a large increase in microbial activity.Other important considerations include the choice of suitable plant species tolerant to salinity/sodicity and local environmental conditions and the addition of balanced fertilizer applications.
基金National Natural Science Foundation of China(Nos.49831070 and 49971046).
文摘The adsorption of methylene blue (MB) on three soil amendments,red mud from Hungary, rd mud from UK and beringite from Belgium, wasstudied to determine the surface areas of the amendments using a0.005 mol L^-1 NaCl solution and deionised water as backgroundsolutions. The surface areas determined by the methylene blue methodin the 0.005 mol L^-1 NaCl solution were 3.357, 2.340 and 5.576 m^2g^-1 for red mud (Hungary), red mud (UK) and beringite, respectively,slightly lower than those in the deionised water system.
