Caliche is known to form in arid climates due to the cementing of soil by which substances?

Caliche forms primarily in arid climates as a result of the process where calcium carbonate and other salts accumulate in the soil, acting as a cementing agent. This phenomenon occurs during periods of evaporation, where water evaporates from the surface, leaving dissolved minerals behind. As water seeps through the soil, it carries these minerals, particularly calcium carbonate, down into the soil layers. Once the water evaporates, these minerals precipitate out and bind the soil particles together, creating a hard, cemented layer known as caliche.

This unique soil feature is indicative of dry environments where evaporation rates exceed precipitation, allowing the accumulation of these soluble salts, which not only contribute to the formation of caliche but also influence soil productivity and water retention in such ecosystems. Other choices do not accurately represent the primary substances involved in caliche formation; for instance, organic matter, while beneficial for soil structure in wetter climates, does not cement soil in the same manner as calcium carbonate and salts do.