I have not heard that expression.
From ;
https://aglab.ars.usda.gov/let-s-get-to-work/plant-growth-and-root-development-resource-material#:~:text=Caliche%20is%20a%20shallow%20layer,semiarid%20areas%20throughout%20the%20world.
Caliche is used in construction worldwide.
Its reserves in the Llano Estacado in Texas can be used in the manufacture of Portland cement; the caliche meets the chemical composition requirements and has been used as a principal raw material in Portland cement production.
Caliche is often a challenge to agriculture.
It interferes with proper soil drainage, the formation of plant roots, and it also can contain soluble minerals that are not beneficial to plants.
The impermeable caliche prevents plant roots from penetrating to deeper soil layers, which limits the supply of nutrients, water, and space, making it difficult for the plants to develop normally.