EAST LINTON, Scotland - A modern take on the age-old farming technique of plowing charred plants into the soil could help tackle climate change and even food security, according to researchers in Scotland.

Their study is looking at biochar, a charcoal like substance produced from heating farm or food waste, which when plowed into the soil can store the greenhouse gas carbon dioxide and may help retain nutrients and water.

The process of making biochar also produces low-carbon energy, including heat and an energy-rich gas which can be burned to produce electricity.

The farmer can use his agricultural residues to produce clean energy. He is off-setting the fossil fuel usage that he would ordinarily have, said Jason Cook, a PhD student at Edinburgh University.

By applying the char to the land he would (also) mitigate the need for oil-derived fertilizers, and lock away the greenhouse gas carbon dioxide.

We don't understand everything -- but it does have huge potential, he said. Some scientists have questioned the benefit of biochar for soil fertility.

Cook is in the second year of biochar field trials at Stonelaws Farm in picturesque East Lothian. It is farmed by Colin Hunter, who remembers a similar technique being used when he was a child.

The farm I was brought up on used to take the ash from the local village and put it on the soil and what we found was that we always got a higher yield on that area of the ground that had the ash put on it, he said.

Hunter has already adopted several environmentally friendly practices including minimum tillage which means he no longer ploughs his fields, reducing his carbon footprint and improving soil quality.

He has also diversified from simply growing oilseed rape, winter wheat and spring barley and now lets holiday cottages on the farm. He says he is particularly interested in harnessing the heat from the biochar production process for both the cottages and his grain drier.

SOIL

Biochar is made by heating plants or wood in airtight conditions to produce a carbon-rich residue. Plants absorb carbon from the atmosphere as they grow. Subsequently storing it in the soil removes the greenhouse gas from the atmosphere.

One scientist estimated that turning 27 percent of global crop waste into biochar and plowing this into the soil could store 0.2 billion tonnes of carbon annually, compared with more than 8 billion tonnes annual global emissions from burning fossil fuels.

Dr Simon Shackley of the UK Biochar Research Center says farmers should be paid for trapping greenhouse gases in the soil. U.S. Agriculture Secretary Tom Vilsack said that payments for low-carbon farm practices will be a vital component of a planned U.S. $80 billion cap and trade scheme.

But the idea of using charcoal to lock greenhouse gases in the soil has critics, ringing alarm bells among some environmentalists that it could spur deforestation. Its chief problem may be that it is barely proven on a commercial scale - something Cook wants to change.

Climate change is real, it is happening and things need to be done here and now about it and this seems a remarkable way of actually doing something about it, he said.
(Reporting by Stuart McDill; editing by Gerard Wynn)

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