Innovative strategies to boost soil carbon propel Australia towards net zero emissions

May 17, 2024

Soil carbon sequestration can play a pivotal role in reducing Australia’s agricultural sector emissions.

Image: Shutterstock

At the heart of Australia’s efforts to achieve net zero emissions by 2050 are the nation’s universities, where researchers are pioneering advanced agricultural practices to boost soil carbon levels.

“Evidence suggests carbon improves soil biodiversity and water retention and decreases erosion,” says Dr Elaine Mitchell, a Research Associate in soil carbon at QUT. “Drawing carbon out of the atmosphere where it’s causing harm and putting it into the soil means healthier, more productive soils.”

Universities are planting the scientific seeds to help bolster farmers’ soil carbon sequestration capabilities. Mitchell’s research, for instance, involves understanding how effective land management can generate long-term soil carbon gains. She’s investigating time-controlled grazing — grazing cattle at a higher density for a shorter duration — which has been shown to increase soil carbon stocks.

Additionally, she found that legumes, particularly species of Desmanthus, have deep tap roots, channelling carbon deep into the soil. They also contain compounds called tannins, “so when the cattle eat them, they reduce the production of methane in their guts,” Mitchell says.

Meanwhile, Annette Cowie, Senior Principal Research Scientist – Climate at the New South Wales Department of Primary Industries and Adjunct Professor at the University of New England Armidale campus, is exploring biochar, a carbon-rich form of charcoal, with researchers at UNE’s School of Environmental and Rural Science.

“As a soil amendment, biochar is much more stable and durable than carbon sequestered by building natural soil organic matter,” she says. 

Cowie adds that biochar is effective at building the soil’s nutrient- and water-holding capacity and reduces its nitrous oxide emissions.

Mitchell views soil carbon sequestration as a “short-term bridging solution allowing us to buy time while other technologies are developed and implemented. 

“It shouldn’t take away the focus from reducing emissions.”

Writer: Rina Caballar

First published in Australian University Science, Issue 11

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