P.PSH.1356 - The potential of biomineral fertilisers to increase soil carbon sequestration

Summary

This project aimed to assess the ability of a biomineral fertiliser to increase soil carbon sequestration, while at least maintaining productivity and profitability in relation to best practice conventional fertiliser use. The project was conducted over three years across five sites in south-west WA, made up of the main trial site, the small plot trial, and three producer demonstration sites. At the main site, no treatment effect was evident and so the hypotheses that the biomineral treatment would increase soil carbon sequestration ahead of the synthetic fertiliser treatment was rejected.

Objectives

Assess the potential of biomineral fertilisers to increase soil carbon, above that of conventional fertilisers.  

Assess the carbon emissions of a biomineral and conventional fertiliser regime in a pasture fed beef system typical of South-West WA.  

Key findings

Overall, the project was unable to measure an increase in soil carbon from the use of biomineral fertilisers, that exceeded that of synthetic fertilisers.

Pasture and cattle growth across the main trial site, and producer demonstration sites showed that biomineral fertilisers can maintain production levels equivalent to synthetic fertilisers, despite drastically less nutrient levels being applied within the biomineral fertiliser regime

The greatest limitation of Biomineral fertilisers identified is cost. They were consistently more expensive than synthetic fertilisers across all sites. This eroded profitability, even though productivity was maintained.

The results demonstrate that biomineral fertilisers are a viable alternative to synthetic fertilisers for pasture-based livestock systems. They maintained productivity and supported equivalent animal performance, while offering modest greenhouse gas reductions through more efficient fertiliser use.

Benefits to industry

The results informed producers that to increase soil carbon and to reduce emissions the required strategy is more complex than simply changing to an alternative fertiliser. 

The project upskilled producers in their ability to understand whole of farm carbon accounting and emissions produced, plus how to generate the benefit cost analysis to measure the impact of alternative fertiliser decisions. 

The project benefited industry by upskilling producers to implement data driven informed fertiliser purchasing decisions around the viability of alternative fertilisers covering both changes in production and the commercial returns of these decisions.

MLA action

This project will inform future research and ongoing extension in the fields of alternative fertilisers, nutrient use efficiency and carbon sequestration, and enterprise emissions accounting.

Future research

Integration with other practices to study synergistic effects of biominerals combined with organic amendments (e.g., compost, manure, biochar) and improved grazing practices.