Fundamentals o f Soil Science
Course Code: Sol 114
Unit III- Lecture 11
AGNIBHA SINHA
Assistant Professor
Dept. Soil Science & Agril.
Chemistry
School of
Agriculture
Soil Crusting
Soil Density & Porosity
Concept
covered Soil Consistency and Plasticity
Soil Color
Soil Color
Soil color provides valuable information regarding the soil
conditions and some proportions of soils. For example, dark
colored soil absorb more solar radiation and warm up faster
than light colored soil.
Determination of soil color
A standard system of
accurate description of soil
color involves Munsell color
chart.
Each color chip is described
by 3 component.
Hue:- Dominant spectral
color
Value:- Relative lightness
or darkness of color.
{Value 0 means black} The notation of 2.5YR5/6 means
Chroma:- Purity of • Hue- 2.5YR
dominant color.[Strength • Value-5
of color] { 0 means • Chroma- 6
neutral grey
Factors Influencing the Soil Color
Mineralogy and chemical composition of soil:-
Presence of manganese oxides imparts black while
glauconite imparts green color and calcium carbonate
imparts white color
Iron compounds:- Yellow, red and brown are mostly
due to presence of goethite, hematite and magnetite
respectively.
Organic matter:- Organic soil present in the soil impart
dark brown to black color on it.
Soil moisture:- Moist soils are darker than the dry soils.
Soil texture and structure:- Coarse textured soil are
usually light in color while well structurted soils appear
to be darker in color.
