Leaf mold (spelled leaf mould outside of the United States) is the

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...

produced by decomposition of shaded deciduous

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

and tree leaves, primarily by fungal breakdown in a slower cooler manner as opposed to the bacterial degradation of leaves.

Description

Leaves shed in autumn tend to have a very low nitrogen content and are often dry. Their main constituents, cellulose and

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...

, are two recalcitrant molecules resistant to degradation. Because of this, autumn leaves break down far more slowly than most other compost ingredients which may take a very long on their own. Specialised biota, such as molds, produce extracellular enzymes which can easily break down those complex plant polymers(cellulose, lignin and hemicellulose) into biologically accessible forms enriching the soil environment. The importance of this decomposition of the leaves and other shed plant litter is that their degradation and decomposition forms a critical step in the mineralization of organic nutrients and their recycling.

Time and process

Fungal decomposition of a heap of leaves in damp temperate climates can take between one and three years to break down into a dark brown fine powdery humic matter. A succession of different fungal species may be involved. A range of micro

detritivore Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

s are also involved in converting the leaf material into a fine-grained humus, including many isopods, millipedes,

earthworms An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...

, etc.

Uses

In the natural environment, the decomposition of leaves provides a moist growing medium for young plants and protects the ground from drying out during periods of low rainfall. It is a significant component of

soil organic matter Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal detritus at various stages of decomposition, cells and tissues of soil microbes, and substances that soil microbes synthesize. SOM provides numerous b ...

, particularly in temperate deciduous woodland. The slow rate of decomposition gradually releases plant nutrients bound up in the leaves back into the environment to be re-used by plants. Autumn leaves are often collected in gardens and farms into pits or containers for the resultant leaf mold to be used later. Oxygen and moisture are essential for leaf decomposition. Leaf mold is not high in nutrient content but is an excellent humic

soil conditioner A soil conditioner is a product which is added to soil to improve the soil’s physical qualities, usually its fertility (ability to provide nutrition for plants) and sometimes its mechanics. In general usage, the term "soil conditioner" is often ...

because its structure and moisture retention provide a good growing medium for seedling roots. Leaves collected from roads and pavements may be contaminated by pollutants which can become more concentrated as the leaves decompose into a smaller volume

References

External links

*BBC Gardening
How to Make Leaf MouldHow to Make Leaf Mould
- Greenfingers.com *UK Gardening
How to Make Leaf Mould
{{DEFAULTSORT:Leaf Mold Composting Soil improvers Permaculture Sustainable gardening Sustainable products Soil Leaves ja:腐葉土

Description

Time and process

Uses

See also

References

External links