private property

How does crp fall under cultivated land? If land is turned into crp, does that land need to be posted private or are you to assume that all crp is cultivated land and therefor private property no hunting?

I would like to know how crp falls under the cultivated land description in the regulations. Do hunters just need to assume that any crp is cultivated and private? Much of the land around idaho has been turned over to crp and is not fenced nor are there any signs posting it as private. How should a hunter/ fisherman know if the land can be accessed without special permission from a landowner?