James Cook University researchers are partnering with Howe Farming in Far North Queensland to explore a groundbreaking method of improving soil health and carbon drawdown by feeding crops crushed basalt.
The project also involves the University of South Australia, Carbonaught, and the TNQ Drought Hub. Together, they are taking a holistic approach to improving soil health, crop productivity and the carbon balance.
Professor Paul Nelson, a soil scientist at JCU said tropical soils are mostly highly weathered and infertile and will benefit from this addition of fresh rock, called 'enhanced weathering'.
"This is the first time the effect of crushed basalt will be tested in bananas and avocados. While we're confident the soils will respond positively, the trials will provide a clearer picture of the broader economic and environmental benefits," said Dr Nelson.
University of South Australia researcher Dr Binoy Sarkar, who is co-lead of the project, said by applying basalt scientists are giving nature a boost.
"The process neutralises soil acidity, and releases nutrients such as calcium, magnesium, phosphorus and potassium. This is shaping up to be a cost-effective way of improving the health of degraded acidic soils,'' said Dr Sarkar.
Dr Nelson said this is the first round of crushed basalt spreading at two trial sites as part of a $4.8 million project supported by the Australian Government through funding from the Climate-Smart Agriculture Program under the Natural Heritage Trust.
A further five trials are planned in sub-tropical and temperate agricultural systems in Eastern Australia.
Dr Nelson said the project will improve soils but also aims to lock up carbon, as carbon dioxide dissolved in soil water can react with the basalt.
"This project is unique as we have installed monitoring systems and automatic samplers to capture runoff and deep drainage during rain events. We know how much basalt is being applied and by measuring changes in the crops, soil, runoff and leachate, we can work out how much carbon is captured through basalt weathering in the paddock, as well as downstream effects," said Dr Nelson.
A further $210,000 grant from Cascade Climate has been awarded to the project, adding significant value enabling deeper investigation into the mechanisms of carbon storage in soils.
Dr Sakar is leading this new phase of the project. "This study looks at how organic carbon storage changes over time and space when basalt is added to acidic soil in Australia, something that hasn't been studied here before," he said.
JCU Senior Researcher Fred Holden is leading the team that has established the Far North Queensland trials. In recent months, they have finalised the experimental design, installed monitoring equipment and completed pre-treatment soil sampling in preparation for this first application of crushed basalt.
"I am grateful to be working on such a novel project. Working with farmers to improve their soils whilst contributing to society's efforts towards climate change mitigation is extremely rewarding. Our research would not be possible without our team, partners and the farm managers who work with us to make these trials possible," Mr Holden said.
Dr Nelson said it's important to develop innovative and collaborative approaches to increasing carbon sequestration.
"If successful, enhanced rock weathering could be scaled up across other agricultural regions, offering farmers a cost-effective approach to increasing productivity and resilience in the face of climate variability."
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