Of this, about 23 million tonnes end up in the nation’s municipal waste – more than double the amount in 1960. Disposing of it costs an estimated US$1bn a year, and less than 3% is recycled.

In addition, about 25 million tonnes of garden waste is generated every year. In 2000, 57% was recovered for recycling.

Unsorted, untreated organic waste is of little use in landfills, where it breaks down slowly, if at all, and contributes to the toxic substances washed out by rain water. In incinerators, its fuel value is low in comparison to other wastes.

But composted properly – allowed to decompose in optimum conditions – it is of potentially high value to a nation whose fertiliser use has more than doubled in the last 40 years.

Compost not only boosts soil fertility, it also increases water and nutrient retention in the soil, reduces erosion, moderates temperature and can suppress weed growth and plant disease.

Recycling organic wastes can be done at a range of levels, from homeowners simply leaving their grass clippings on their lawns to nourish the soil, to programmes for collecting, sorting and processing wastes at huge municipal compost heaps.

Even composting, however, is not without its environmental impacts. Decomposition produces carbon dioxide and, in some cases, methane - both greenhouse gases. Large-scale composting can be smelly, and the energy use and the emissions of the machinery used in collecting, shredding and turning the waste as it decomposes are also factors.

There are also environmental and health risks associated with the composting of contaminated waste. Washington State, for example, banned the herbicide Clopyralid on lawns after studies showed that compost made from treated grass clippings harmed some crop types.