3. • Soil color is a property that can be used to describe horizonation and soil
morphology.
• The change in soil color with depth is directly related to a variety of
processes that are occurring in the soil.
• The soil color doesn’t affect the properties of the soil, but provides insight
environmental conditions, formation processes and other influences on the
soil.
• Used in classifying soil.
Soil Color
4. • Soil color doesn’t affect the behavior and use of soil, however, it can
indicate the composition of the soil and give clues to the conditions that
the soil is subjected to.
• Soil can exhibit a wide range of colors like gray, black, white, red,
brown, yellow and green under different conditions.
Soil Color
5. Soil color is due to three main pigments:
• Black: From organic matter
• Red: From iron and Aluminum oxides.
• White: From silicates and salts.
Color can be a useful indicator of some of the general properties of a soil,
as well as some of the chemical processes that are occurring beneath the
surface.
Classification of Soil Color
6. Soil color is influenced by the amount of proteins present in the soil.
• Yellow or red color indicates the presence of iron-oxides.
• Dark brown or black color in soil represents that the soil has high organic matter
content.
• Wet soil appears darker than dry soil.
• The presence of water also affects the soil color by affecting the oxidation rate.
Soil that has a high water will have less air in the soil, specifically less oxygen.
• In well drained (oxygen-rich) soil red and brown color caused by oxidation are
more common, as opposed to wet (low oxygen) soils where soil usually appears
grey.
Causes of Soil Color
8. Soil Coloring
Soil color is influenced by the amount of proteins present in the soil.
• Yellow or red color indicates the presence of iron-oxides.
• Dark brown or black color in soil represents that the soil has high
organic matter content.
• Wet soil appears darker than dry soil.
9. Determination of Soil Color
The Munsell color book is used to determine the color of soil.
