Mishná sur Péa 6:13

The following divide a field for peah: a stream, a pool, a private road, a public road, a public path, a private path in constant use in summer and the rainy season, fallow land, a plowed field and a different seed. One who harvested for animal fodder, [the plot] serves divides, the words of Rabbi Meir. But the sages say: it does not stop for peah unless it is plowed.