LOTS OF HORSE POWER IS NEEDED
Mechanical diggers were needed to provide a more efficient way of removing potatoes from the ground. These diggers eliminated the need to remove potatoes from the rows by hand, although there were some workers with hand diggers who could keep up with the early mechanical diggers.
Victor potato digger, Littleton, c. 1920
Southern Aroostook Agricultural Museum
Two horses were necessary to pull these early potato diggers. The mechanical parts of the digger were powered by the wheels, hence the wheel cleats that can be seen in the photo on the left.
The rotating arms on the digger on the right were also powered by the wheels. The arms would dig into the row and throw the potatoes and rocks off to the side. A person would not want to be in the way. It's likely that this type of digger bruised potatoes. Needless to say, this rotating arms design did not catch on.
Since horses both pulled the digger and powered the digger mechanism, the horses tired easily. They had to rest frequently or were replaced by another team of horses.