This is an illustration for the month of March, from a 15th century illuminated book of hours commissioned by Jean, Duc de Berry (his residence can be seen in the background).
According to The Medieval Garden Enclosed, March was the time of the year when farmers began to plow their fields in preparation for sowing. This activity corresponds to the Ace of Pentacles, when one gets to work laying a foundation in order to reap a future harvest. It is the starting point of the labor necessary to achieve one's particular goals. This lovely image brings the ideas expressed within this Tarot card literally down to earth.