Low availability of soil phosphorus is limiting organic grain production in Australia. Consequently, development of the organic food sector is being held back by a shortage of organic grain that is needed in almost every corner of the sector, from bread and breakfast cereals, through to organic animal industries such as dairy and poultry. Organic growers cannot use superphosphate to supply phosphorous for their crops, but they may use rock or soft phosphate, or tailor-made compost with elevated phosphorus levels.

A possible alternative for organic farmers might be the use of wastewater precipitation products such as struvite or calcium phosphate. Struvite is a slow release phosphorus and magnesium fertiliser that is produced from the decant water of anaerobic digestion facilities processing wastewater from municipal, food processing or intensive animal industry sources. Alternatively, calcium phosphate can be produced but will generally result in reduced phosphorus capture efficiency.  
The project will seek to clarify whether and under which conditions particular sources of phosphorus derived from wastewater, such as struvite or calcium phosphate, can be allowed as inputs in certified organic farming systems in Australia.

Also, if allowed in other countries, which are those countries and under which conditions is the use of these compounds allowed? If wastewater precipitation products are not allowed inputs into organic farming systems at present, what possibilities are there to have this input accepted in the future? This project will seek to answer key questions concerning the situation in Australia and internationally.

Answers to these questions, together with a cost benefit assessment of using phosphorus inputs currently allowed in Australian certified organic farming systems in comparison with potential future alternatives, will be presented in a discussion paper. The paper will be published on the Organic Trust Australia website, and sent to stakeholders such as the Australian organic certifying bodies. The aim is to get the results of the project into the public domain and to organic farmers in particular.

Location: Gatton/St Lucia

Project members

Mr Johannes Biala

Research Centre Manager
School of Agriculture and Food Sciences

Associate Supervisor: Dr Paul Kristiansen (University of New England)