What does mottling in soil indicate?

Mottling in soil refers to the presence of irregular spots or stains of different colors, which typically indicate variations in moisture levels. This phenomenon occurs when soil has been saturated during certain periods, leading to changes in its chemistry and physical characteristics. The mottles often reflect the oxidized (drained) and reduced (saturated) states of soil minerals, which can signal fluctuating water levels over time.

This is particularly important in assessing the drainage capacity of soil, as patterns of mottling can help inform land use decisions, agricultural practices, and the design of engineered systems like onsite wastewater treatment. Understanding mottling allows for better predictions of water movement and retention within the soil profile.

In contrast, other options might discuss aspects of soil chemistry or drainage, but they do not capture the primary significance of mottling as an indicator of moisture status and variability.