What does the term "shrink-swell potential" refer to?

The term "shrink-swell potential" specifically pertains to the tendency of certain types of soil, particularly clay-rich soils, to undergo significant changes in volume in response to moisture content variations. When soil is saturated with water, it can absorb moisture and swell, increasing in volume. Conversely, when the moisture content decreases, the soil can shrink, resulting in a reduction in volume. This characteristic is particularly important in construction and agricultural applications, as it can lead to ground instability, cracking, and other structural issues if not properly accounted for.

The other choices refer to different properties of soil that do not align with the definition of shrink-swell potential. For instance, the potential of soil to lose moisture content is more about drying and does not capture the volume change aspect that is central to shrink-swell behavior. The capacity of soil to absorb contaminants relates to soil pollution and retention properties rather than physical dimensional changes. Finally, variability in soil density with moisture changes is a broader concept that discusses density fluctuations but does not specifically highlight the dimensional expansion or contraction associated with shrink-swell potential.