Soil colour
is an important indicator of soil health including mineral composition, soil
organic matter, soil fertility, soil moisture, drainage etc as well as the past
and present oxidation-reduction conditions of the soil. Soil color is also used
to distinguish soil horizons. Soil displays a wide range of colors according to
presence of minerals and organic content in it. For example, soil having
brown/dark brown/black colour indicate the presence of organic matter, darker
is the colour more will be the organic matter; yellow/pale brown indicated presence
of iron oxides, poor organic matter and nutrients; white colour indicates
presence of calcium and silica, red colour indicates presence of iron. All soil
colors display darker under wet condition and lighter in dry condition, therefore determination
of soil colour should
be done under uniform conditions. Early morning and late evening readings are
not accurate. The soil colour is determined by using Munsell colour chart. In
his chart different colour chips are systematically arranged by three variables
namely Hue, Value and Chroma. Hue indicates the spectral colors like red, yellow, blue, green etc; Value indicates
lightness or darkness of the colour on a scale; Chroma indicates the range of
strength of colour on a scale. The combination of these three variables is used
to describe the colour of a soil. Â
Figure: Different Colored Soils
