Quantifying fertiliser phosphorus use efficiency in Vertosols across the Northern regions

The PhD project investigates phosphorus (P) use efficiency in wheat grown on Vertosols in Australia’s Northern Grain Region (NGR), where long-term cultivation and low fertiliser inputs have reduced soil P fertility. Only about 20% of applied fertiliser P is taken up in the first year, with 70–80% becoming fixed in the soil through sorption or precipitation- an issue intensified in the NGR due to calcium-rich soils that restrict P solubility. The inefficient recovery of applied P, combined with the need to increase crop production, led to a global increase in P fertiliser use, with current global use 17 million tons per year, far exceeding the safe planetary boundary. This highlights the urgent need for scientific research into sustainable phosphorus management. This project will quantify crop recovery of fertiliser P and assess the contribution of residual soil P from past applications. Using radiotracers (P-32 and P-33), labelled MAP will track P movement in soil-plant systems. Field and glasshouse experiments, combined with chemical extractions and isotope analysis, will identify key P pools and improve understanding of P dynamics. The outcomes will support more efficient fertiliser use and enhance the sustainability of Australian grain production.

Research Higher Degree Scholarship