The landowner or other persons may enter the premises according to the provisions of the lease. The landowner does not have unlimited rights to enter the premises. Typically, the landlord is required to give reasonable notice to enter the premises for inspection or other purposes. If the parties agree that the landowner may enter the premises frequently and casually, this should be acknowledged in the lease. This arrangement gives the landowner a non-exclusive (shared) right to certain parts of the premises. For example, the landowner and the tenant may agree in the lease to have the landowner visit periodically to jointly inspect the premises, or the landowner may permit certain individuals to use an access road crossing the fields. See the FAQ: What rights might a landowner reserve?