Soil carbon calculators emerging

The scientific community is working hard to make the soil carbon opportunity real. Soil carbon calculators put knowledge intothe hands of the land manager. We will cover as many as we find.

C-Calc is a calculator that compares the amount of carbon added to the soil from management practices. It calculates carbon input based on paddock yields. The benefits of different rotations over a decade or longer can be revealed so that practices that improve soil structure are selected.

DPI principal research scientist Peter Fisher, who headed the project, says the project was driven by landholder concern over soil degradation. UC-Calc lets growers select paddocks vulnerable to soil problems and choose rotations to build up soil carbon.

"Growers can start to understand how much carbon they're applying, what difference that will make in the long term and how they can change it," he says in Ground Cover. The amount of carbon being added to the soil, as this is the key controllable factor.

Dr Fisher says soil with a carbon level below 2% will degrade. "A level of two per cent or above prevents soil degradation on most soils, and if you're above that threshold you get other benefits, such as increased nutrients, soil resilience and water-holding capacity - the value of soil carbon can explain about 60 per cent of the variation in soil structure."

Dr Fisher found most high-organic-matter paddocks outperformed their paired site over a number of seasons across 14 irrigated wheat, canola, rice and maize paired sites in northern Victoria and southern NSW.

The researchers found that increasing organic matter by 2t/Ha/year for 10 years, organic carbon levels will be 0.4% higher than if the extra organic matter had not been added.

Dr Fisher says perennial pasture maintained the highest carbon levels. Maintaining stubbles, increasing pasture in rotations, growing higher-yielding crops or plants with larger, more active root systems boost organic matter and carbon levels.

The project was funded by the Victorian Department of Primary Industries (DPI) and the GRDC.


More information: Peter Fisher, 03 5833 5341, peter.fisher@dpi.vic.gov.au