The importance of soil carbon cannot be understated.
There is no alternative to soil.
Soil scientist John Crawford from the University of Sydney’s Institute for Sustainable Solutions calculates that the soil in the world’s agricultural land will run out in 60 years.
When you consider the amount of topsoil lost in the past 100 years the figure of 60 years starts not to look daft.
He is concerned with making sure the world’s seven billion people get something to eat.
Australia is at the forefront of soil carbon science and policy-makers here are ahead of the curve when it comes to thinking about ways to reward farmers for improving soil quality by building soil carbon content.
The Federal government is establishing a framework that will reward good agricultural practice. We need to give farmers the resources to manage the eco-system services that we’ve all taken for granted with soil being the major part.
Soil health is at the root of most of the challenges that society faces in the next 30 years – food security water supply energy climate change and health.
Soil is the basis for human health and agriculture is the basis for civilisation. There is great historical evidence that most of the great ancient civilisations fell as a result of decline in their soil.
We cannot achieve food security without improving the quality of the land whether climate change happens or not. Food production is number one but while we are putting carbon back in the soil it also mitigates climate change. If we could get a tiny increase in carbon content in soils across Australia’s range lands it would have a huge impact because we have so much range land.
Building soil carbon will involve paying farmers to return crop residues to the land. A carbon price for soil carbon of $20-$25 per tonne is realistic. This is not talking about a subsidy – it is talking about payment for eco-system services. To make the market operate with confidence an independent auditor is needed.
There is a threshold carbon level of between 1.1% and 1.5% in the surface layer of the soil and if the carbon content goes below that then the soil functions begin to deteriorate.
Most soils in Africa and Asia and some areas of Australia have a carbon concentration as low as 0.1%.
The techniques to return carbon to the soil are well known but it can be a long process.
Alex McBratney of the University of Sydney has developed a soil carbon mapping tool.