What does "leaching" refer to in the context of soil?

Leaching refers specifically to the process where substances, often including nutrients and minerals, move downward through the soil profile as a result of water movement. This process can be influenced by rainfall or irrigation, where water carries dissolved materials away from the upper layers of soil to deeper layers or into groundwater.

This downward movement can significantly impact soil fertility and water quality, as essential nutrients may be washed away from the root zone of plants. Understanding leaching is crucial for effective soil and water management in agricultural practices, especially in aquatic environments where runoff can carry pesticides and fertilizers into water bodies.

The other concepts, while related to soil or water, do not accurately describe the process of leaching. Accumulation of nutrients signifies retention, while erosion relates to the physical removal of soil rather than movement due to water. Evaporation refers to the transformation of water from liquid to vapor, which is a separate process from the downward movement of substances through the soil.