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Field capacity

Field capacity has been defined as the soil moisture state when, 48 hours after saturation or heavy rain, all downward movement of water has ceased. It is the water content retained at low suctions (5-33kPa) depending on soil type, and is the upper limit of plant available water.

Fine texture

(i) A broad group of textures consisting of, or containing, large quantities of fine fractions, particularly silt and clay. Includes sandy clay, silty clay, and clay texture classes. (ii) When used in reference to family particle-size classes in U.S. and FAO soil taxonomy, is specifically defined as having 35 to 60 percent clay. See also soil texture.

Fluvioglacial deposits

Material moved from the margins of glaciers and subsequently sorted and deposited by streams flowing from the melting ice.


Science of landforms that studies the evolution of the Earth's surface and interprets landforms as records of geological history.


Al(OH)3. Mineral with a platy structure, that occurs in highly weathered soils and in laterite.

Glacial drift

Unstratified deposits laid down directly beneath the ice or dropped from the surface as the ice melted.


Large masses of ice that form by the compaction and recrystallization of snow under freezing conditions; glaciers often move downslope or outward in all directions because of the stress of their own weight; they may be stagnant or retreating under warming conditions.

Glaciofluvial deposits

Material moved by glaciers and subsequently sorted and deposited by streams flowing from the melting ice. The deposits are stratified and may occur in the form of outwash plains, deltas, kames, eskers, and kame terraces. See also Glacial drift and till.

Glaciolacustrine deposits

Material ranging from fine clay to sand derived from glaciers and deposited in glacial lakes by water originating mainly from the melting of glacial ice; many such deposits are bedded or laminated with varves.

Gley soil

Soil formed under naturally wet or waterlogged conditions as evidenced by grey colours stemming from the reduction, under anaerobic conditions, of ferric iron to the ferrous state.

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