Which condition is characteristic of a traffic pan in soil?

A traffic pan in soil refers to a compacted layer formed due to the repeated pressure and weight applied by vehicles, machinery, or foot traffic. This compaction results in soil particles being pushed closer together, which creates a dense layer that significantly restricts the movement of water and air.

The characteristic feature of this compacted layer is that it hinders natural processes essential for healthy soil ecology, such as the infiltration of water and the exchange of gases. The inability of water to permeate through this layer can lead to pooling of water on the surface, adversely affecting plant roots and the overall health of the soil. This is particularly detrimental for plant growth, as roots require both water and air to thrive.

Other options describe conditions that do not align with the nature of a traffic pan. For example, promoting root growth or enhancing water retention suggests a soil condition conducive to plant health, which is opposite of what a traffic pan creates. Similarly, quick drainage is not characteristic of a compacted layer, as this layer creates barriers to drainage rather than facilitating it. Understanding these distinctions is crucial for effective soil management and land use planning.