Friday, August 26, 2011

Carbon Farmers cautioned against unsound science

Farmers interested in increasing carbon sequestration in their soils should beware reports coming out of the Soil Carbon Research Program (SCRP) because they mistake conventional farming for ‘carbon farming’. “Carbon Farming, under the Carbon Farming Initiative, requires a change in land management with a switch to one or more new practices, not business as usual. Yet the reports coming out of the SCRP claim to give results over periods of 30 and 40 years which make no reference to changes in land management,” says Michael Kiely, chairman of the Carbon Farming & Trading Association. The results of a stocktake of soil organic carbon on the Esperance sand plain are the first revealed in WA from the national SCRP. The Department of Agriculture and Food WA (DAFWA), cautioned farmers interested in increasing carbon sequestration, as the Esperance results showed changes might be small and would occur slowly over time. “Scientists cautioning farmers against expecting to grow soil carbon are like the scholars who predicted that Columbus would sail off the end of the earth because it was flat. They could say that only because they hadn’t been there.” Mr Kiely maintains that scientific studies commonly under report carbon sequestration rates for many reasons. “They focus on a limited number of practices one at a time, whereas carbon farmers usually apply several techniques together,” he says. “The combined effect of these practices applied with the skill of an experienced carbon farmer explains why they commonly report soil carbon sequestration rates up to 10 times those recorded by scientists.” Another reason for under-reporting is failure to sample soil deep enough in sandy soils. “Roots from perennials have been recorded reaching down as far as 7 metres in WA. Where there are roots there is carbon. These SCRP reports are based on only 30cm samples.” The most commonly-quoted ‘fact’ quoted to scare farmers rears its head in this report: soil carbon ties up nutrients such as N and P which are needed for plant growth, making them unavailable and therefore requiring that expensive fertilizer be added. “We need plant growth for carbon sequestration as well, so we have this Alice in Wonderland proposition: we can’t grow soil carbon because it will prevent the growth of soil carbon,” he says. But the “C locks up N, P and S” Conundrum exists only in the world of Theoretical Soil Chemistry. It takes no account of the impact of carbon on factors such as water retention and Phosphorus availability, he says. “Again, conventional science sees sequestration as a zero/sum game instead of the win/win proposition that it is.” The research is funded by the Australian Government’s Climate Change Research Program and the Grains Research and Development Corporation.

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