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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 2017-12-06, 00:00 authored by Benjamin JonesBenjamin Jones, R Haynes, I PhillipsThe 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
91Issue
11Start Page
2281End Page
2288Number of Pages
8eISSN
1095-8630ISSN
0301-4797Location
UKPublisher
Academic PressPublisher DOI
Full Text URL
Language
en-ausPeer Reviewed
- Yes
Open Access
- No
External Author Affiliations
Alcoa of Australia; TBA Research Institute; University of Queensland;Era Eligible
- Yes