I believe that legally, the landowner has a right to keep any structures put on the place. It needs to be specified in the lease if you wnat to build and keep something. If it is a permanent structure, like an elevated permanent blind, the landowner has the rights to it when the lease expires unless otherwise specified.
It is sort of like if you rent a house and put up new blinds, shutters, put in new windows or ceiling fans. You can't "uninstall" the stuff when you move out.
I believe things like feeders, which are easily portable are the personal property of the leasee and can be taken when the lease expires.
That's my understanding.