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Mushroom Growers and Researchers Use Coal and Quarry Waste to Save Rare Peat Bogs

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25.05.2004

Researchers at the University of Warwick have found a way of using some the most difficult waste material from coal mines and quarries that will also significantly reduce the rapid depletion of the world’s best peat resources.

The researchers in the University of Warwick’s horticultural research arm, Warwick HRI, have been able to develop new substitute products from quarry and coal mine waste which can replace some of the 250,000m³ of peat are used each year for growing mushrooms in Britain and Ireland and even more peat used for “blocking compost” in propagation of other plants.

One of the new products, developed by University of Warwick researcher Professor Ralph Noble at Warwick HRI, uses very fine quarry waste from Staffordshire to replace peat used in “blocking compost” for some plants. The other product uses very fine coal tailings waste Yorkshire to replace 30% of the heavy black peat in the “casings” used in mushroom growing.

Both these waste materials are very difficult to dispose of normally as their very fine nature can make them unstable when put into landfill. This new use for this otherwise difficult to dispose off material is doubly environmentally friendly as the material saves vast quantities of our rarest and most valuable peat boglands.

The coal tailings product is now being sold by Tunnel Tech Ltd and has already captured about 20% of the mushroom casing market. Mushroom growers use it not just because of the ecological benefits it brings but also because it brings clear economic and growing benefits. The use of the coal tailings also reduces the need to add lime to the mix, produces a very clean mushroom, and produces very good yields of mushroom crops.

The environmental benefits of the technology have also been the salvation of the oldest mushroom house in the world still in production. National Trust’s Hanbury Hall in Worcestershire, built in 1860, it still uses the original slate shelves for growing beds of mushrooms. With the National Trust adopting a peat-free policy by the end of 2002, the production of plants in all its gardens had already been successfully transferred to peat-free growing media, the exception to date being mushroom production. The lack of a viable peat alternative in mushroom casing consequently threatened the continuing production of mushrooms at Hanbury Hall. The Warwick HRI scientists were able to create a mix of 70% bark and 30% coal tailings that completely replaced the peat and allowed the world’s oldest mushroom house is to be able to continue growing mushrooms under the National Trust’s peat-free policy.

The initial research was funded by the Department for Environment, Food and Rural Affairs (Defra) and the mushroom industry, through the Horticultural Development Council (HDC), have provided £350,000 of funding to research alternatives.

Peter Dunn | Source: University of Warwick
Further information: www.newsandevents.warwick.ac.uk/index.cfm?page=pressrelease&id=1918

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