Cabbages the size of footballs, onions that fill the palm of your hand and delicious gooseberries now grow on land where the soil was considered so poor that farming ceased 50 years ago. The secret is the 420 million year old volcanic rock dust waste which Moira and Cameron Thomson have mixed with municipal compost and spread on their smallholding on a hillside several miles out of Pitlochry (Scotland). The fruit and vegetables are highly nutritious (if soils are high in minerals, so is the produce grown in them) and more resistant to pests and diseases.

Moira and Cameron believe that re-mineralised soils take carbon dioxide out of the atmosphere more effectively than untreated soils. If proven, and the use of rock dust was adopted worldwide, it could play a part in reducing levels in the atmosphere. Global carbon levels could be reduced further by using rock dust rather than fossil fuel-based chemical fertilisers and pesticides.

The couple's experience and beliefs are now being put to the test. In 2003 the Scottish Executive invested over £95,000 in three years of field trials to monitor soil fertility, microbial activity, crop yield, nutritive cycling and the soil's potential for absorbing and holding carbon dioxide. If the trials show that adding rock dust to municipal compost improves its quality as a fertiliser, it would also be a boon for local waste authorities. Soon organic waste will not be allowed into landfill. When it rots down it produces methane, another greenhouse gas.

Their Sustainable Ecological Earth Regeneration (SEER) Centre is open to visitors from the 1st April to the 31st October from 10am to 6pm. For more information on the Centre and where you can buy rock dust, contact: SEER, Ceanghline, Straloch Farm, Enochdhu, Blairgowrie PH10 7PJ Tel.: 01250 870180 website: www.seercentre.org.uk

Ed.- (i) The Camerons were alerted to the potential of rock dust by John Hamaker and Don Weaver's book The Survival of Civilisation.

(ii) Highlights from rock dust research worldwide include:

• In Europe, remineralising soil with basalt dust resulted in a four-fold increase of timber volume after 24 years for pine seedlings. The improvement was maintained for 60 years from that one remineralisation.

• Australian researchers noted fivefold increases for some tree species. Potting out times reduced from five months to six weeks

• A study in Michigan, US, found that corn yields more than doubled without additional irrigation

(iii) Soil is a combination of particles of rocks, minerals and organic matter produced through weathering processes. Soil remineralisation mimics the natural processes of glaciation. During ice ages glaciers and walls of ice scrape backwards and forwards over the Earth's surface. Any soil is quickly lost, and the underlying rocks are ground into dust and fine material. This dust contains a wide range of minerals and is suspended in the ice in huge quantities. When the ice melts the mineral dust is deposited over the Earth’s surface. As plant life slowly returns. the dust mixes with leaves from early trees and forms soil.