In the context of soil formation, what does the term "leaching" refer to?

Leaching refers to the process by which soluble substances are washed out from the soil due to the movement of water through it. As water percolates through the soil layers, it dissolves minerals and nutrients and carries them away, often moving them towards groundwater or removing them completely from the topsoil. This process is essential in soil formation and nutrient cycling but can also lead to a depletion of vital nutrients necessary for plant growth.

While other options discuss various aspects of soil science, they do not accurately define leaching. The movement of water through soil actually encompasses a broader concept than just leaching, as it includes any form of water passing through the substrate, whether it enhances or diminishes nutrient content. Accumulation of minerals, formation of organic material, and loss of soil nutrients all relate to soil composition and health but do not capture the specific mechanism of nutrient loss due to water action that leaching describes.