What is the requirement for coloration in a spodic horizon?

The characteristic coloration of a spodic horizon is typically described as dark brown or black. This is due to the accumulation of organic matter, particularly humic substances, which can create a visibly dark color in the soil profile. Spodic horizons are formed under specific conditions, often in sandy or acid soils, where organic matter and iron oxides accumulate, further contributing to this dark coloration.

This coloration is a critical identifying feature of spodic horizons in soil classification and indicates a specific pedogenic process that involves leaching and the movement of materials within the soil profile, highlighting the horizon's development in relation to its environmental conditions. The other color options do not accurately reflect the typical appearance of a spodic horizon, which is inherently linked to its organic content and the processes occurring in that layer.