DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY
Leaf mould and commercial peat-based compost, on a background of garden soil in Norfolk, UK.The garden soil has many small stones, sand particles, and plant remains. In addition, unseen, it contains bacteria, fungi and animals including insects, worms and molluscs. Leaf mould (left heap) also contains animal life, is dark due to the presence of organic materials (humus), but poor in plant nutrients and not a good growing medium on its own. The peat-based compost (right heap) is high in organic material, retains water well, but has a low mineral content and requires artificial fertilisers to sustain good plant growth. Commercial composts are subjected to a sterilising process that kills weed seeds, soil animals and pathogenic micro-organisms. This process may also destroy beneficial micro-organisms such as Rhizobium species ( nitrogen fixing bacteria ) and mycorrhizal fungi.
Model release not required. Property release not required.