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Effect of amendment of bauxite processing sand with organic materials on its chemical, physical and microbial properties

journal contribution
posted on 06.12.2017, 00:00 by Benjamin JonesBenjamin Jones, R Haynes, I Phillips
The effects of addition of a range of organic amendments (biosolids, spent mushroom compost, green waste compost and green waste-derived biochar), at two rates, on some key chemical, physical and microbial properties of bauxite-processing residue sand were studied in a laboratory incubation study. Levels of exchangeable cations were not greatly affected by additions of amendments but extractable P was increased significantly by mushroom and green waste composts and massively (i.e. from 11.8 to 966 mg P kg(-1)) by biosolids applications. Levels of extractable NO(3)(-)-N were also greatly elevated by biosolids additions and there was a concomitant decrease in pH. Addition of all amendments decreased bulk density and increased mesoporosity, available water holding capacity and water retention at field capacity (-10 kPa), with the higher rate having a greater effect. Addition of biosolids, mushroom compost and green waste compost all increased soluble organic C, microbial biomass C, basal respiration and the activities of beta-glucosidase, L-asparaginase and alkali phosphatase enzymes. The germination index of watercress grown in the materials was greatly reduced by biosolids application and this was attributed to the combined effects of a high EC and high concentrations of extractable P and NO(3)(-). It was concluded that the increases in water storage and retention and microbial activity induced by additions of the composts is likely to improve the properties of bauxite-processing residue sand as a growth medium but that allowing time for soluble salts, originating from the organic amendments, to leach out may be an important consideration before sowing seeds.

History

Volume

91

Issue

11

Start Page

2281

End Page

2288

Number of Pages

8

eISSN

1095-8630

ISSN

0301-4797

Location

UK

Publisher

Academic Press

Language

en-aus

Peer Reviewed

Yes

Open Access

No

External Author Affiliations

Alcoa of Australia; TBA Research Institute; University of Queensland;

Era Eligible

Yes

Journal

Journal of environmental management.