The most difficult soil riddles

White Sands, having 442 total square kilometers of dune fields, is the world's largest surface deposit of gypsum. Unlike other desert sands, it is cool to the touch, due to the high rate of evaporation of surface moisture and the fact that the sands reflect, rather than absorb, the sun's rays.

In areas of harsh winters the depth of the permafrost can be as much as 1,493 m (4,898 ft) in the northern Lena and Yana River basins. The overlying active layer that seasonally thaws is just 0.6–4 m (2.0–13 ft) thick.

Moles are pests to agriculture and gardening. However, they do not eat plant roots; they only cause damage indirectly when they dig through soil to find earthworms and other small invertebrates in the soil.

Chernozem (pictured, literally black earth) is a soil containing a high percentage of humus. It is very fertile and produces a high agricultural yield. Chernozem occurs in many places in the world, but it is the most common and the deepest in Ukraine. Throughout its history, Ukraine has been one of the powerhouses of world agriculture due to its fertile conditions.