As part of the multi-disciplinary team comprising personnel from the University of Western Australia, WA Department of Primary Industry and Regional Development, Adelaide University, Murdoch University and two fertilizer companies, the research associate will carry out the laboratory, glasshouse and field studies and other relevant research required to quantify key processes controlling soil P storage, supply and response in wheat, canola and lupins.
Tasks will include:
Formulation of specific hypotheses and optimisation of detailed experimental design to test these. Consideration will be given to (i) characterising processes governing P availability along the soil profile, (ii) determining the relationship between root structure/function and P acquisition, (iii) correcting low subsoil P availability, (iv) quantifying draw-down of soil P over time and the effect of low P fertilizer rates on crop growth and grain yield, etc.
Collect and analyse soil and plant samples
Compile/process/present data, including statistical interpretation
Contribute to writing manuscript(s) for submission to high-impact journals, and
Other duties as directed
Please see link below for full applicant information.
Final advertisement – Research Associate UWA
Abstract. The exchange rate of inorganic phosphorus (P) between the soil solution and solid phase, also known as soil solution P turnover, is essential for describing the kinetics of bioavailable P. While soil solution P turnover (Km) can be determined by tracing radioisotopes in a soil–solution system, few studies have done so. We believe that this is due to a lack of understanding on how to derive Km from isotopic exchange kinetic (IEK) experiments, a common form of radioisotope dilution study. Here, we provide a derivation of calculating Km using parameters obtained from IEK experiments. We then calculated Km for 217 soils from published IEK experiments in terrestrial ecosystems, and also that of 18 long-term P fertilizer field experiments. Analysis of the global compilation data set revealed a negative relationship between concentrations of soil solution P and Km. Furthermore, Km buffered isotopically exchangeable P in soils with low concentrations of soil solution P. This finding was supported by an analysis of long-term P fertilizer field experiments, which revealed a negative relationship between Kmand phosphate-buffering capacity. Our study highlights the importance of calculating Km for understanding the kinetics of P between the soil solid and solution phases where it is bioavailable. We argue that our derivation can also be used to calculate soil solution turnover of other environmentally relevant and strongly sorbing elements that can be traced with radioisotopes, such as zinc, cadmium, nickel, arsenic, and uranium.
For the full text please follow the link: https://www.biogeosciences.net/15/105/2018/