NEET BIOLOGY

Detailed explanation-1: -The iron and manganese particles have been leached out due to high amounts of rainfall or drainage. This colour indicates good drainage. Iron found within the soil is oxidised more readily due to the higher oxygen content. This causes the soil to develop a ‘rusty’ colour.

Detailed explanation-2: -Brown soils, often referred to as brown forest soils or brown earths, are well drained with brownish subsoils where iron oxides created through weathering processes are bonded to silicate clays.

Detailed explanation-3: -Well or moderately well-drained soils appear brownish, while poorly drained soils appear gray. Somewhat poorly drained soils generally appear gray because they usually have gray clay films, many of which show in the wall of the pit.

Detailed explanation-4: -Soil color is produced by the minerals present and by the organic matter content. Yellow or red soil indicates the presence of oxidized ferric iron oxides. Dark brown or black color in soil indicates that the soil has a high organic matter content. Wet soil will appear darker than dry soil.

Detailed explanation-5: -Many soils are brown in color because they contain large amounts of carbon. In particular, carbon-containing polymers called humic compounds absorb most visible wavelengths of light and give soils a dark brown appearance.