USC00006 - Can novel oxalate-containing metal-open-frameworks be used as fertilisers and alkalinity sources in acidic soils utilising soil bacteria?

This study investigates a new family of fertiliser compounds developed at Southern Cross University (SCU) for their fertilising and alkalinising effects.

Acidic soils, and iron-rich soils (e.g. kraznozems) in particular, retain phosphate irreversibly at pH < 5.5 and require liming to raise pH and release phosphorous for plant uptake. Without liming, crop yields in these soils are often reduced and/or require excess fertiliser additions to keep nutrient supply sufficiently high. This new fertiliser contains oxalate, which in soil media can be used by bacteria to produce carbonate and raise soil pH. The oxalate is part of the fertiliser structure, such that oxalate solubility and bacterial consumption will control the activity of these compounds in soils.

This research will provide baseline data to assess these compounds as potential agricultural fertilisers to provide macro- and micro-nutrients and increase the pH of acid soils growing grain crops (e.g. wheat). Our model fertiliser has been demonstrated to have desirable fertilising properties including sufficient water solubility and the ability to improve nitrogen and phosphorous concentrations in the soil. Preliminary work using our model fertiliser on radish showed promising results, with increased stem height, thickness, edible-root mass and increased leaf area. This project will extend our work to Dollarbird, a 'flagship' wheat cultivar, on an iron-rich acid soil in an expanded, fully-replicated pot trial.

There are two expected outcomes from this research. Firstly, identification of the bacterial pathways that lead to increased bio-availability of nitrogen, phosphorous and other micro-nutrients within the soil. This will demonstrate the ability of soil bacteria to degrade and grow utilising our model fertiliser as a carbon and energy source. Secondly, insights to the efficiency and efficacy of the model fertiliser in producing cereal grain crop growth (Dollarbird wheat cultivar).