Soil scientists, agronomists and grain growers from across Australia have come together in Adelaide for an important National Soil Acidity Workshop.
The workshop was hosted by the South Australian Research and Development Institute (SARDI), the research division of the Department of Primary Industries and Regions, South Australia (PIRSA). It was a chance for the 62 attendees to share experiences and learnings and to discuss strategies for addressing soil acidity at a national, state and regional level.
Dr Giacomo Betti, GRDC Manager Sustainable Cropping Systems – South, said, "Soil acidification is a serious issue in every cropping area of Australia."
"However, different regions are at different stages of addressing soil acidity as a constraint on production".
In addition to reviewing research projects underway in South Australia, New South Wales, Western Australia and Victoria, presenters also explored strategies for applying and incorporating lime with a particular focus on no-till cropping systems.
"We heard compelling evidence from researchers that strategic lime applications could significantly increase yields, particularly in valuable and acid sensitive break crops, such as lentils and faba beans," Dr Betti said.
Delegates were also given insights into innovative projects to improve acid soil management, from a more visible pH testing powder developed at the University of Adelaide, to experiments in using spectroscopy to measure lime penetration through the soil profile.
On Day 2 of the workshop, key industry researchers from a range of state-based research agencies and government agriculture departments gathered to review their acid soil management learnings and identify gaps in their knowledge and research areas.
These discussions helped identify and prioritise areas of future research, development and extension investment, considering where transformational gains could be made in identifying, preventing and better managing acid soils across Australia. Dr Betti said the meeting confirmed that significant work is being done to address soil acidification, but that research efforts appear to be fragmented across the different regions.
"The workshop was very useful for all involved, with key researchers in this critical area valuing the opportunity to sit down and identify important trends, opportunities and research actions," he said.
"GRDC is confident this more collaborative approach will encourage further cooperation between the state-based researchers, to deliver improved findings and on-farm strategies that help ensure healthy soils and consistent yields for Australian grain growers," Dr Betti said.
Soil acidification in South Australia
Brian Hughes, a soil scientist at SARDI says South Australian grain growers are experiencing rising rates of soil acidification, including sub-surface acid layers, due mostly to the widespread adoption of no till cropping systems and increased crop productivity.
Dr Giacomo Betti, GRDC Manager Sustainable Cropping Systems – South and Brian Hughes, PIRSA-SARDI Soil Scientist say the National Acid Soils Workshop delivered a range of insights for managing soil acidity in SA cropping systems. Photo: Belinda Cay, AgCommunicators
"The workshop gave people an opportunity to hear about the SA projects addressing different aspects of soil acidity including soil pH mapping, lime sources, breeding tolerance, alkalinity of other farm inputs, innovative methods of measuring pH and acidity – as well as statewide summaries on areas likely to become acidic and results from local trials," he said.
"We also discussed SA growers' concerns about lime applications encouraging snails.
"The value of bringing in knowledge from other states and sharing our learnings was clear, with the audience receiving a range of insights for managing soil acidity as part of 'normal' farming in the future."
Soil acidity has been a developing constraint to crop production in Australia becoming more significant over the last few decades, especially on sandy soils where pH can drop rapidly.
Low soil pH reduces the availability of nutrients for plant growth and can increase aluminium in the soil solution that can be toxic and impair root growth. In addition, the rhizobia in most pulses are particularly sensitive to soil acidity.
Current recommendations regarding liming rates are based upon historical research under conventional farming systems, characterised by high levels of soil disturbance and significant mechanical incorporation of surface-applied lime, and developed for high rainfall conditions. Therefore, the relevance of lime rate recommendations in current farming systems may require refinement to account for lower rainfall, different soil types and other alkaline inputs.
The 2025 National Soil Acidity Workshop was held in Adelaide as part of the GRDC Acid Soils Southern Region project (Updating acidification rates, lime recommendations and extension aids to overcome soil acidity constraints to crop production in the southern region).
The project is a collaboration between the South Australian Research and Development Institute (SARDI), the University of Adelaide, South Australian Department for Environment and Water (DEW), Trengove Consulting and AgCommunicators.
For more details, visit acidsoilssa.com.au.
