One question, what is hard pan soil even though I have my ideas what it can be. We have a few. Black clay, you need hammer and chisel, pickaxe fails. We have a layer of sedimentary type of rock formation which becomes concrete when lime and other organic material starts its action on it. I consider it a kind of sandstone but brittle, not like black clay. Then we have a white clay, though it is not as hard as black but behaves like a waterproof plastic/rubber layer. We use it as a waterproof layer on our roofs.
Can the above be considered as hard pan or is it something else?
Regards,
Arif.
