WRAP, the government’s Waste and Resources Action Programme will be examining the risks of applying waste-derived compost to grazing land following concern from farmers and retailers.
At the time of going to press, risk assessments for both green waste compost and food waste compost were expected to start. The latter may include field trials.
The work stems from concerns raised by Quality Meat Scotland (QMS), the certification body for cattle and sheep farms. In October it placed a moratorium on its members using waste-derived compost "until key answers can be provided to legitimate questions on human and animal health".
It is concerned about the presence of viruses like foot and mouth, and noxious weeds like ragwort. These, it says, could survive the temperatures achieved by the composting process. "Nobody’s looked at the application of compost to grazing land," said Andy McGowan, QMS’s industry development manager. "Given what our industry’s gone through before - with foot and mouth likely to have come from catering waste - there’s enough cause for concern."
Composting capacity is expected to grow by two million tonnes in the next five years according to draft figures from the Composting Association. About 3.4 million tonnes of waste was composted in 2005/06, producing just over 2 million tonnes of compost, with half used in agriculture. Some 12% of that was supplied to grassland.
Given these figures, a moratorium on compost’s use on grazing land might not have a major impact on the market for waste-derived compost, but some producers would need to increase supply to landscape or land restoration projects, said Emily Nichols, the Composting Association’s technical manager.
In December, the British Retail Consortium backed QMS’s concerns. In a policy paper, published on its website, it said "further research and thorough risk assessments should be conducted before committing to the use of compost on a much wider scale".1 It has few concerns about the use of compost from green waste on cereal crops or grazing land, although it would like "clarification" on "the possible ingestion by cattle of toxic plants", the possible presence of pesticide residues and the microbiological load of waste-derived compost. Some crops - especially those eaten raw - could be affected by high loads. Farmers may need guidance on application rates for grazing land, it adds.
However, it has "major concerns" about compost made from food waste containing meat. "We know that the BSE prion is not eliminated by heat," it says, "and as BSE was linked to animals ingesting other animal proteins, we are concerned about the spreading on grassland of this type of material." A review of the current residence time and temperature requirements for composting kitchen waste is needed, it said.
ADAS, the consultants conducting the risk assessments for WRAP, is confident it can assuage the farming industry’s concerns, but Mr McGowan said farmers are unlikely to want to take the risk of applying food waste compost to land regardless.
WRAP is "in discussions" with the BRC about developing a framework for the application of different types of compost to different crops and soil types.