Question

give the reason for variation of soil colour at different places

Answer 1

Soil color 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 colour; gray, black, white, reds, browns, yellows and under the right conditions green.  The development and distribution of color in soil results from chemical and biological weathering, especially redox reactions. As the primary minerals in soil parent material weather, the elements combine into new and colorful compounds. Soil conditions produce uniform or gradual color changes, while reducing environments result in disrupted color flow with complex, mottled patterns and points of color concentration.