In a new study, Australian researchers have used digital techniques to predict how soil organic carbon may be altered by climate change.
“Soil organic carbon is a major determinant of soil health,” says Jonathan Gray, senior scientist at New South Wales Office of Environment & Heritage, who was the lead author of the study. “It influences many chemical, physical, and biological properties of the soil, such as fertility and water holding capacity.”
The researchers used 12 climate change models to predict how soil organic carbon levels vary with climate change. The models used in the study reflected a full range of projected global climate outcomes. Results were varied. “A majority of models showed a decline in soil organic carbon with climate change,” states Gray. “But a few of the models actually predicted an increase.”
The researchers also discovered that the extent to which soil organic carbon changes varied across soil types, current climate, and land use regimes. For example, the projected average decline of soil organic carbon was less than one ton per hectare for sandy, low-fertility soils in dry conditions under cropping regimes. It was 15 times as much for clay-rich, fertile soils in wet conditions under native vegetation regimes.
“This knowledge can help us to better understand and predict where the greatest potential losses or gains in soil carbon may occur,” says Gray. “It would allow us to better prepare for and adapt to altered soil conditions,” he says. “That would ultimately improve how we manage both agricultural and native ecosystems.”
Photo Caption: Jonathan Gray collecting soil carbon data in the field, Hawkesbury Region, NSW (D. King, OEH)
Photo Credit: D. King, Office of Environment and Heritage.