Wed 07 Dec 11, 11:14am AEDT
By Anna Salleh
Fungi and other microbes can reorganise the structure of soil so it is able to absorb more water and carbon say researchers.
Biophysicist, Professor Iain Young, of the University of New England, and colleagues, report their findings today in the Royal Society journal Interface.
"If you just look at soil without life, the structure is pretty random but life actually makes order within the soil," says Young.
"Bacteria and fungi take on a little feng shui and they can rearrange the soil particles."
Young describes soil as "the most complex biomaterial on the planet".
"In a handful of fertile soil there are more individual organisms than the total number of human beings that have ever lived on the planet," he says.
"The life in soil defines the soil and its function and properties."
Scientists have long known that soil microbes exude glue-like chemicals that bind the soil and change its structure.
Young and colleagues hypothesised that microbes could improve the porosity of the soil, helping the flow of water and gasses, such as oxygen and carbon dioxide.
The researchers first confirmed this hypothesis with a computer model of soil and biology.
Then they tested it with a sample of agricultural soil.
Using high-resolution microtomography, which uses x-rays to visualise the soil in 3D, the researchers compared the pores in sterilised soil with those in soil that had microbes added to it.
"Hey presto, what we found was that the biology was doing a remarkable thing. It was actually increasing the porosity in the soil, particularly fungi," says Young.
The researchers found the soil with microbes had more pores, which were more ordered and connected.
Young says fungal hyphae (filaments) also stabilise the structure of soil, while bacteria exude surfactants that reduce surface tension, making it easier for plants to suck up water from the soil.
"Really microbes are the architects and plumbers of the soil," he says, adding that greater biological activity also increases the amount of carbon sequestered by soils.
Young says the new knowledge could be used to rehabilitate compacted soils and to create 'designer soils' with specific porosity and ability to sequester carbon.
"We've got the beginnings of a new science that allows us to try and manipulate the microbial activity to actually design the soils for the purposes we wish," he says.
Young is also involved with the Cooperative Research Centre for Polymers in designing synthetic biopolymers that mimic biology's ability to improve aeration and water retention of soils.