Fields of Green: Cabbages

Description from the publisher:

This card does something different than every other card introduced so far in the game. It has an Ongoing ability (as indicated by the blue frame and the word "Ongoing" at the bottom-right corner). Contrary to immediate effects which apply once when you play the cards, or Harvest abilities for which you have to pay the cost each Harvest phase, ongoing abilities are always "on". You can take advantage of them as many times as they allow you to!

In this particular case, the Cabbages ask you to build Livestock cards around them. The more you build, the more Food they will generate! (and don't forget those nice 2 victory points at the end).