Freeze-thaw cycles: How not to mix soil

The repeated cycles of ground freezing and thawing that occur in many places don’t do a good job of churning the soil, a new study suggests.

Freeze-thaw cycles and the burrowing of animals are among the many natural phenomena that can mix the upper layers of Earth’s soil, says James M. Kaste, a geologist at Dartmouth College in Hanover, N.H.