title: Novel predictors of soil genesis following natural weathering processes of bauxite residues.
abstract: Bauxite residue often has chemical and physical limitations to support plant growth, and improving its matrix properties is crucial to support sustainable vegetation in the long term. Spontaneous vegetation colonization on deposits in Central China, over a period of 20 years, has revealed that natural weathering processes may convert bauxite residue to a soil-like medium. Residue samples from different stacking ages were collected to determine the effect of natural processes on matrix properties over time. It was demonstrated that natural processes decreased pH (10.98 to 9.45), electrical conductivity (EC) (3.73 to 0.36 mS/cm), and exchangeable sodium percentage (ESP) (72.51 to 28.99 %), while increasing bulk density (1.91 to 1.39 g/cm(3)), improving the mean weight diameter (MWD) of water-stable aggregates (0.24 to 0.52 mm), and the proportion of >0.25-mm water-stable aggregates (19.91 to 50.73 %). The accumulation of organic carbon and the reduction of ESP and exchangeable Na had positive effects on soil aggregate formation, while exchangeable Ca and Mg were significantly beneficial to aggregation of water-stable aggregates. Climate, stacking time, and biological factors appear to improve the structure of bauxite residue. Our findings demonstrate soil genesis occurring following natural weathering processes of bauxite residues over time.
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhu
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China. sgxue70@hotmail.com.
authors.forename: Shengguo
authors.initials: S
authors.lastname: Xue
authors.affiliation: Crop and Environment Sciences Department, Harper Adams University, Newport, Shropshire, TF10 8NB, UK.
authors.forename: William
authors.initials: W
authors.lastname: Hartley
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Huang
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Wu
authors.affiliation: School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002681:China; D008906:Mining; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D014887:Weather
chemical_list: D012987:Soil; D012989:Soil Pollutants; D000537:Aluminum Oxide
keywords: Bauxite residue; Matrix properties; Natural weathering processes; Soil genesis