A LEADING soil scientist has promoted pulses within cropping rotations as the key to reducing carbon emissions related to grain growing.
Ram Dalal, of Queensland's Department of Environment and Resource Management, said the inclusion of pulses in farming systems reduced carbon emissions associated with the manufacture and transport of nitrogen fertiliser.
"Including a grain legume and grass phase in farming systems increases carbon sequestration," Dr Dalal said.
"Even after accounting for methane emissions from grazing animals, it reduces energy use and carbon emissions."
Dr Dalal said if farmers wanted to balance energy input and energy output, a major shift in land use was required.
"If you go from cereal cropping to a certain phase of pasture, you will put soil carbon into the ground at the rate of about half a tonne per hectare per year," he said.
"If you want to realise the full potential of carbon, you would need to look at moving to plantation forestry or permanent pastures."
Speaking at the recent Grains Research and Development Corporation Research Update at Goondiwindi, Dr Dalal presented options to increase carbon sequestration and reduce nitrous oxide and atmospheric methane emissions from farming so as to reduce the gap between energy input and energy output.
"Farming has always essentially been about carbon farming," he said.
"We estimate that over a 60-year period of cereal cropping under continuous cultivation, soils of northern NSW and southern Queensland have lost more than 40 per cent of carbon a hectare.
"In southern Australia, in some areas - but not all - agriculture started in the 19th century on lower nutrient soils that needed phosphate fertiliser and other nutrients to get clover established.
"In Queensland, however, the fertility has been higher.
"But once you get into cropping, the decline is very similar in southern Australia as it is in the north."
