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Testing for Phosphorus in Soils

Testing for Phosphorus in Soils

Much of the soil in Australia, and particularly in Western Australia, is naturally low in phosphorus due to extensive exposure to the atmosphere. Whilst native Australian plants have adapted to survive on a limited phosphorus intake, introduced species, including agricultural crops, have not evolved. In order to survive, these plants require the addition of phosphorus in the form of a fertiliser.

The need for phosphorus fertiliser has in effect had specific implications for applications in the agriculture industry of Australia. Similarly, applications have also developed in mine site rehabilitation, which is a compulsory step to environmental sustainability in the mining industry. As such, success and sustainability in these applications require a detailed understanding of specific soil nutrient conditions.


The Use of Water-soluble Phosphorus Fertilisers 
Due to the critical and limiting nature of phosphorus in our soils and the need to ensure crop fertility in the agriculture sector, alternative environmental systems have been developed over time. One such development has been the use of water-soluble phosphorus fertilisers, which are applied in a dissolvable or ‘water soluble’ form to plants.

Water-soluble phosphorus fertilisers are, however, heavily susceptible to losses through soil retention and reaction, erosion and leaching. Particularly, as these fertilisers are not immediately available for plant uptake, increased concentrations of phosphorus may potentially lead to problems with eutrophication where water quality and the ecology within the water body is affected when phosphorus fertilisers runoff into waterways. Here, these excess concentrations of phosphorus may stimulate the growth of algae. When the algae die or are eaten, oxygen levels are reduced and toxins are released, which may hinder water use for fisheries, industry, recreation and drinking.

Considering the possibility of such environmental devastation, it is therefore important that an effective fertiliser application program is in place to not only achieve productive crop yields in agriculture processes, but also ensure the sustainability of a preferred native vegetation in mine rehabilitation applications.

Available phosphorus determined through soil analysis by Envirolab can be used to establish a fertiliser application program.


Why Use Soil Testing from Envirolab for your Agriculture Decisions
Fertile soil drives agricultural production and regular testing provides you with the information you need to make the right decision about the selection of suitable fertiliser programs.

As the Inorganics Team Leader at the Perth laboratory of Envirolab, I’ve been involved in assisting clients with a comprehensive range of soil testing, including the varied analyses for the determination of Phosphorus availability for plant uptake. In leading the Inorganics Team, flexibility in our service offering has been essential in tailoring quotes to your specific testing requirements.



References and Further Reading 
Australian Government Department of Industry, Innovation and Science, (2016). Mine Rehabilitation - Leading Practice Sustainable Development Program for the Mining. [online] Available at

Lines-Kelly, R. (1992). Why Phosphorus is important. Soil Sense. [online] Available at

Quinlan, R and Wherret, A. (2017). Phosphorus. [online] Available at Rayment, G and Lyons, D. (2011). Soil Chemical Methods – Australiasia.



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