How soil gets colour and what the colour indicating?
The soil colour gives an indication of the various processes going-on in the soil as well as the type of minerals in the soil.
The red colour in the soil is due to the abundance of iron oxide under oxidised conditions (well-drainage) in the soil; dark colour is generally due to the accumulation of highly decayed organic matter; yellow colour is due to hydrated iron oxides and hydroxide; black nodules are due to manganese oxides; mottling and gleying are associated with poor drainage and/or high water table.
Abundant pale yellow mottles coupled with very low pH are indicative of possible acid sulphate soils.
Colours of soil matrix and mottles are indicative of the water and drainage conditions in the soil and hence suitability of the soil for aquaculture.
Parameters: Soil colour is described by the parameters called hue, value and chroma. Hue represents the dominant wave length or colour of the light; value, refers to the lightness of the colour; chroma, relative purity or strength of the colour.