The Science on Soil Carbon is NOT in

The 19 finalists in this year’s Carbon Cocky of the Year Award all have one thing in common: they mix and match a combination of land management practices to enrich their soils. “This could explain why carbon farmers report higher rates of carbon sequestration in their soils than government research agencies that only ever study the effect of a single practice at a time,” says Michael Kiely of awards organiser Carbon Farmers of Australia. For example, the winners of the Carbon Cocky of the Year Award, Yass district graziers John and Robyn Ive, combine controlled grazing with water-spreading, strategic tree plantings, and soil additives (such as sewage ash and poultry manure). Braidwood grazier Martin Royds, winner of the Best Practice Award, combines grazing management, pasture cropping, and soil treatments, including Biodynamic preparations, compost teas, and worm juice. Spring Ridge mixed farmer Cam McKellar, winner of the Outstanding Leadership Award, combines direct drill, controlled traffic, fish emulsion, humates and molasses/sugar as a microbial stimulant, as well as composting and cover cropping.

This is the on-farm reality that has yet to be studied and, until it is, we must say that the science of soil carbon is not yet in. When research reports tell us our soils can only accumulate carbon at a tiny amount per year, they are actually saying ‘We can only manage to sequester this much using this one practice’. While the CSIRO has measured soil carbon increases up to 0.3tonne/hectare as the maximum possible, carbon farmers such as pasture cropping pioneer Col Seis from Gulgong have recorded increases of up to 9 tonnes/hectare using the same laboratories for analysis. It is common for skilled carbon farmers to report 2%-3% increases in soil carbon over the past decade, which included the worst drought in living memory.

Carbon Graziers often combine grazing management with pasture cropping and soil amendments. Carbon Croppers combine no-till with mulching and crop rotations, cover crops, composts, and even animals as four-legged composting units. In the 5 years the Awards have been running, a rising trend has been the adoption of on-farm composting or production of worm juice nutrients and the integration of trees in the landscape. The Ives have counted 250,000 new trees on their 250 ha property, with direct production benefits. The Carbon Cocky of the Year Award was judged by experts from the Department of Primary Industries and the Department of Environment, Climate Change and Water, plus last year’s winner, and presented at a gala dinner as part of the Carbon Farming Conference, 28-29 September, 2011 in Dubbo NSW.

There was a high level of innovation among the entries: “One finalist composts almond hulls and back-loads his truck with hulls for delivery as a feedstock to a feedlot where he collects manure for his composting operation. Another has invented a process called ‘delving’ which brings clays up into the top horizon of sandy soil for better carbon sequestration,” he says.

The Carbon Cocky of the Year Awards started 5 years ago with the support of the Central West and Lachlan CMAs as a means of encouraging practices that promote soil health. This year the Awards attracted entries from Western Australia, South Australia and Victoria as well as NSW.

Despite the image of innovative farmers lacking the data required by ‘evidence-based science’, the finalists were keen to prove their claims by providing data.

If we could only allow entries featuring grazing and cropping practices that are based on ‘best available science’ we could not hold these awards because science has yet to study the combinations that carbon farmers use. In fact the best available science is being conducted by farmers in the biggest laboratory of them all: in the paddocks of Australia where a practice either works or it doesn’t and the amount on the cheque the farmer receives is the final test result. Word of mouth does the rest.

Most of the practices chosen by carbon farmers are not endorsed by peer-reviewed science. Yet most of the winners of all the ‘farmer of the year’ awards programs use grazing management which is not supported by research.