Long term monitoring of the effectiveness of Alkaloam™ as a soil amendment

The waterways of the Peel-Harvey Catchment located about 70km south of Perth have a long history of nuisance and toxic algal blooms and subsequent loss of amenity and even significant fish kills.¹ These algal blooms occur at higher incidences than would naturally be the case due to the loss of nutrients applied as fertiliser throughout the catchment to the regional waterways. These nutrients originate from both urban and rural land, but much of the issue of nutrient loss to waterways from the rural properties is due to the poor ability of the native soils to retain nutrients – especially phosphorus – applied as agricultural fertilisers. Staff and students of SESE, together with staff of the Department of Agriculture and Food, Western Australia (DAFWA) are working on a number of fronts to address this issue – one of which is a project which aims to ameliorate the soils of farming properties and enhance their ability to retain phosphorus.

The environmental and agricultural value of using the fine residues from the processing of bauxite into alumina (also referred to as Red Mud, but now trademarked as Alkaloam™) as an amendment for sandy soils has been extensively investigated over many years. DAFWA, Alcoa World Alumina Australia (Alcoa) and farmers in the Peel-Harvey Coastal Plain Catchment have worked together on the use of Alkaloam within the Peel-Harvey. Research shows that the material is useful in reducing the amount of phosphorus exported from farmland into waterways, while also increasing the productivity of amended pastures. To comply with WA Environmental Protection Authority approvals, extensive research and monitoring continues to be undertaken by DAFWA and other organisations showing the usefulness and environmental safety of Alkaloam as a soil amendment.

Contact
Mark Rivers

¹An overview of the history and ecohydrology issues of the Peel Inlet and Harvey Estuary is available for download below.

A paper on the Alkaloam project, presented at the 6th International Alumina Quality Workshop in 2002, is available for download below.

Nuisance and sometimes toxic algal blooms due, in part, to loss of phosphorus and nitrogen from rural and urban land continue to occur in parts of our coastal waterways.

Alkaloam™ is spread on the soils of farming properties at rates around 10 tonnes per hectare. This reduces nutrient loss by up to 80% while increasing pasture productivity by around 30%

Median monthly phosphorus concentrations measured in drain water before and after soil-amendment with Alkaloam™