Australian research explores impact enhanced efficiency fertilisers on grain farming

The EEFs trialled will target key nitrogen loss mechanisms such as denitrification, nitrate leaching and volatilisation in different cropping regions and quantify crop nitrogen uptake to determine nitrogen use efficiency and return on investment. Photo: Arjun Pandey/University of Melbourne

Australian grain growers are set to advance nitrogen use efficiency and drastically cut on-farm greenhouse gas (GHG) emissions through a national research project delving into enhanced efficiency fertilisers (EEFs).

These innovative fertilisers leverage chemical or physical methods to fine-tune nitrogen release, synchronising nutrient supply precisely with crop demands to mitigate nitrogen loss risks.

Led by the University of Melbourne and supported by a AUS $17.33M (US $11.58M) investment from the Grains Research and Development Corporation (GRDC), the four-year initiative brings together multiple research organisations and industry partners.

Nigel Hart, Managing Director of GRDC, underscores the strategic importance of this investment in addressing grower concerns over escalating input costs and sustainability challenges in agriculture. “We are keenly aware of the pressures our sector is facing from high input costs, particularly for nitrogen”, Hart emphasises. “There is a very real need to ensure we are using the most efficient fertilisers in the most efficient way.”

According to Hart, the research – led by GRDC’s partners at the University of Melbourne – is critically important with the increasing need to understand and reduce emissions. “This is a part of the long-term sustainability goals of farming operations and Australian agriculture more broadly.”

A number of EEF technologies are commercially available but relatively little is known about their efficacy in different climates and agroecosystems, and their economic and environmental benefits to the grains industry. Photo: David Maunsell

Recommendations for growers

Project lead Associate Professor Helen Suter from the University of Melbourne explains that a number of EEF technologies are commercially available but relatively little is known about their efficacy in different climates and agroecosystems, and their economic and environmental benefits to the grains industry.

“Growers are looking for recommendations of what technologies work where, when, why and how, to make informed decisions about their nitrogen management strategies”, Suter says. The project will establish a network of field trials across Australia in representative soils and cropping systems, where commercially available EEF technologies will be evaluated alongside conventional nitrogen fertilisers.

These technologies include urease inhibitors (to reduce ammonia loss), nitrification inhibitors (to reduce nitrous oxide, nitrogen and leaching loss), dual (urease and nitrification) inhibitors and controlled release fertilisers (both targeting all loss pathways).

Controlled-environment studies will complement the field-based activities, allowing a mechanistic understanding of soil nitrogen cycling and loss pathways, and will support modelling activities aimed at quantifying the environmental impact and potential nitrogen use efficiency gains associated with the use of EEFs across the grains industry.

Improving nitrogen use efficiency

The EEFs trialled will target key nitrogen loss mechanisms such as denitrification, nitrate leaching and volatilisation in different cropping regions and quantify crop nitrogen uptake to determine nitrogen use efficiency and return on investment.

The fate of nitrogen will be tracked in soils and plants using nitrogen-15 stable isotope labelled fertilisers. GRDC sustainable cropping systems manager Cristina Martinez said EEFs had been raised across several GRDC National Grower Network (NGN) forums, particularly in Western Australia, and were front-of-mind for many growers given increasing sustainability requirements.

“Enhanced efficiency fertilisers are a potential option for reducing on-farm GHG emissions while also improving nitrogen use efficiency”, Martinez says. “There are a few reasons for their low adoption amongst grain growers, which include higher cost , relative to standard fertiliser products, uncertainty about how they perform in the field and the return on investment they provide.”

Return on investment

The project will demonstrate the effectiveness of these alternative fertiliser technologies within the grains industry and provide growers with clear recommendations regarding which technologies will perform best in their production systems to maximise return on investment, Martinez expects.

The project will run for four years, with results anticipated to be available to growers from 2028. Project research partners include the University of Melbourne, Department of Primary Industries and Regional Development Western Australia, University of Queensland, New South Wales Department of Primary Industries, CSIRO, Queensland Department of Environment, Science and Innovation, Queensland University of Technology, La Trobe University, Birchip Cropping Group and Hart Field Site Group.

Industry partners include CSBP Limited, Incitec Pivot Fertilisers, Nutrien Ag Solutions, N-Shield and Fertiliser Australia.