As at other plantations in the Yoknapatawpha fictions, there is a gate, probably a fairly formal structure, where the drive up to the Sartoris' big house meets the public road.
The pasture at the Sartoris place would have been used for grazing and making hay to feed their livestock. In Bayard's memory of the summer before "Retreat" takes place, when he and Ringo ran across it to escape the Yankees, it seemed to be endless.