Soil carbon protects crops against disease

Some farmers on Eyre Peninsula in South Australia lost up to 90% of their crops in 2007 to rhizoctonia, a disease that shrivels roots. But farmers in the mid-north Avon district were not affected. The difference between the two districts is soil carbon.

Adelaide University researcher Sjaan Davey, who is comparing soil from Eyre Peninsula and from Avon in the mid-north, said the mid-north has higher carbon levels, which could be making the difference. More rainfall and less soil disturbance are part of the answer. But no-till alone isn’t the answer: "Maybe despite the fact that a lot of people are maintaining residues and doing the direct drill and all of that there's just not enough carbon going back into the system," she said.