DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY DR JEREMY BURGESS / SCIENCE PHOTO LIBRARY
A sample of gardener-made leaf mould, against a background of garden soil, in Norfolk, UK. Leaf mould is made by raking fallen leaves in the autumn and stacking them in heaps, or, for small quantities, enclosing them in black plastic bags. Degradation of the leaves takes place due to the presence of fungi, bacteria and small animals, including worms. This picture shows the stage of the process after 12 months. This is insufficient time for the total degradation of twigs. Leaf mould made this way contains large amounts of humus, and small amounts of mineral particles such as sand. It is low in plant nutrients, but improves soils to which it is added by introducing micro-organisms, together with a carbon source for them. The picture shows that garden soil has larger stones within it, and that its carbon content is lower ( giving rise to a lighter hue).
Model release not required. Property release not required.