You don't have to move splits, but if you don't the foragers will just return to the mother hive. If you move the bees outside their normal foraging range, usually around 3 miles, they will reorient to that new location because they don't recognize where they are. I've never done this, but I'd imagine you only need to leave them there one or two nice weather days to facilitate the reorientation, and then you could move them back. When you did, the foragers would re-reorient to that new location in your original yard and not return back to the mother hive they came from.
I don't have a second yard, so when I make splits, like I did today in fact, I just be sure to load them up with capped brood to replace the foragers lost back to the mother hive and enough food to last until those new bees are hatched.
Another method is to switch the positions of the hives in the yard, so the new split is at the location of the mother hive and vice versa, so the foragers return to the split instead of their original colony. This can deplete the original colony of foragers though, so in this situations it's the mother colony that will need capped brood and stores instead of the split.