What does the presence of iron or manganese nodules in soil indicate about its drainage capability?

The presence of iron or manganese nodules in soil serves as a significant indicator of poor drainage conditions. These nodules usually form in waterlogged environments where oxygen levels are low, leading to the reduction of iron and manganese compounds. When the soil remains saturated with water for extended periods, these elements precipitate out, resulting in the formation of the nodules.

In an environment with good drainage, these minerals would typically not accumulate since excess water would facilitate proper aeration and prevent the reduction processes needed for nodule formation. Thus, finding these nodules strongly suggests that the soil retains water, indicating that the drainage capability is inadequate. This understanding is crucial for evaluating soil health and making informed decisions regarding land use, agriculture, or landscaping.