How are salt flats called solonchaks formed in the Karakum Desert?

In the Karakum Desert, solonchaks—saline areas characterized by high concentrations of soluble salts—are primarily formed through the evaporation of subsoil water.1

This process occurs because, in arid regions, water containing dissolved salts often moves upward toward the land surface. As this water evaporates or is transpired by plants, the salts are left behind in the soil. Because these environments experience high evaporation rates and limited precipitation, the salts accumulate near the surface rather than being leached away.23

Additionally, human activity can accelerate this process; in the Karakum, large-scale irrigation projects have led to secondary salinization, where the rise of saline groundwater creates a salty crust that renders the soil infertile.4