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Silt a soil texture with more than 80 percent silt. Alternatively, a particle size fraction ie a detrital particle finer than fine sand and coarser than clay, generally in the diameter range of 0.02 to 0.002 mm in international system and of 0.05 to 0.002 mm in USDA (United States Department of Agriculture) system. Actually it is a loose aggregate of rock or mineral particles of silt size. Silt is also an important inorganic constituent of soil particles present in mineral components in the solid phase.
Like sand, silt also originates in soil
as weathering products of primary rocks and fragments of rock. Silt is
also an integral part of soil texture and is directly related to properties
of the soil, like porosity, density, consistency etc. The properties of
silt fractions are somewhat intermediary between sand and clay. Because
of being finer in size, silt fractions cover large effective surface areas
which in turn possess absorptive and retention capacities for holding
moisture, gases and nutrients for soil flora
and fauna.
However, soils having a high proportion of silt are relatively difficult
to bring under cultivation. Most floodplain
sediments have a silt content. This is specially so in the case of brahmaputra,
jamuna
and meghna
sediments.
[Rameswar Mondal]
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