Glossary of Terms in Soil Science

valley train

An outwash terrace extending down a valley away from the ice front.

value color

The relative lightness of color, which is approximately a function of the square root of the total amount of light. See also Munsell color system, hue and chroma.

variant ( soil)

A soil whose properties are believed to be sufficiently different from other known soils to justify a new series name, but comprising such a limited geographic area that creation of a new series is not justified.

varve

A distinct band representing the annual deposit of sedimentary materials regardless of origin. It usually consists of two layers; a thick light-colored layer of silt and fine sand laid down in the spring and summer and a thin dark-colored layer of clay laid down in the fall and winter. Because low temperatures are important in delaying the settling of the clay particles it is assumed that varve formation can occur only with glacial waters. The salts of seawater prevent the formation of varves of this kind. The electrolytes in seawater cause flocculation resulting in a homogeneous mass.

vermiculite group

A group of hydrous platy clay minerals similar to the smectite group but having a higher net permanent charge and often larger particle size.

vertical zonation

Altitudinal zonation of soils. See also latitude zonation.

very coarse sand

See separates, soil and texture, soil.

very fine sand

See separates, soil and texture, soil.

very fine sandy loam

See texture / soil.

void

Space in a soil mass not occupied by solid mineral matter. This space may be occupied by air, water or other gaseous or liquid material.

void ratio

The ratio of the volume of void space to the volume of solid particles in a given soil mass.

volume weight (Obsolete)

See bulk density.