Fermentation Layer

Part of the Organic Horizon, which mainly consists of partly decomposed plant material, typically leaves, but also including basal sheaths and twigs if on wooded areas of trees or shrubs. It sits below the Litter Layer. It is also called the F Horizon/Layer/Zone.

  Fertile Soil

A soil which has an adequate range and quantity of nutrients which are available for plant growth. In addition, the soil will have a good soil structure, will have adequate drainage to ensure waterlogging, if it occurred would be a short-term temporary feature, and a suitable quantity of organic matter would be present to ensure a good soil ecology is maintained.

  Field Capacity

The maximum amount of water retained by a soil after natural drainage from gravity has occurred. This is typically up to 3 days after a soil has been thoroughly wetted from heavy rainfall and it has worked its way through the soil profile. Field capacity is the starting point for what is termed Available Water Capacity, and it has also been known as Field Moisture Capacity.

  Field Moisture Capacity

Another name for Field Capacity.

  Fine Earth

All mineral particles (sand, silt and clay) which pass through a 2mm sieve. Particles greater than this are often called the Coarse Tail.

  Fines

Soil particles which are 0.125mm in diameter and less. This includes Clay, Silt, and Very Fine Sand. Fines help to retain water within a soil, but too many fines contribute to a poor drainage capability.

  Flocculation

The coming together of small soil particles into larger aggregates to provide an improved soil structure. Adding sulphur to an alkaline soil, or lime to an acid soil can encourage flocculation.

  French Drain

A trench which has a drainage pipe at the base and is infilled with gravel to the surface. These might typically be installed around field perimeter areas and especially at the base of embankments.

  Friable

A soil that is easily worked. It crumbles into a fine texture, without forming clods of soil.

  Gley Soil

A type of soil which is saturated / waterlogged for long periods during the year. These soils will often have a high content of clay particles with poor aeration and drainage. Gley soils will often smell due to wet decaying organic matter and from anaerobic decomposition. Gley soils are often a mottled colour being blue-grey to grey, with included orange mottling where iron is oxidised within the soil. Typically, the bluish colour is more related to longer or permanent periods of saturation, whilst the orange-brown mottling is more prevalent where saturation is more limited, primarily over

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