We have a lot of rocks here, so in the springtime we roll the alfalfa fields with a cultivator and roller (see some of my previous videos).
In this video, we're using a 1947 (48 model year) John Deere Model A to pull a weighted roller. The purpose of the roller is simple--to push rocks down into the ground to assist in less damage to the swather (windrower) and other equipment.
It was also a good excuse to get the Model A out and put some seat time on the machine.