I hate to admit the Million Dollar Rain thread brought some questions to mind.
Wherever you go people are talking about sub-soil moisture. On The Radio, on this forum, at the seed store, elevator farm supply stores and the list goes on and on.
Yes subsoil moisture has to do with the amount of moisture in soil.
But:1) at what depth is sub soil measured? 2) How is it measured? and what is adequate and at what level is it too low?
A quick check on the internet showed it is measured down to 5 ft in Iowa and 3 1/2 ft. in California. Likely it might be different in other states?
This might be an interesting exchange of ideas.