In which situation do lower chroma colors increasingly appear?

Lower chroma colors are often associated with reduced conditions in the soil, which occur when iron oxides are transformed and released from the soil matrix due to changes in saturation and aeration levels. This process frequently happens in wet, anaerobic environments where the soil is overly saturated with water. Under such conditions, the presence of water can facilitate the leaching of iron, leading to the formation of colors that are less vibrant and lower in chroma.

When iron is removed from the soil, what remains is typically comprised of minerals and organic material that exhibit less color intensity, resulting in soil with a grayish or muted hue. This is in contrast to soils where iron is present, which often display richer reds and yellows indicative of higher chroma. Consequently, the correlation between the removal of iron and the appearance of lower chroma colors is well-supported by the understanding of soil chemistry and color development.