Farmville Crop Mastery

FarmVille has new game update which is Crop Mastery. Harvesting will now be rewarded with Mastery while in plowing and planting, you get an XP.

With Crop Mastery, you will notice that crops has 3 stars which is the crop level. For one star, you need to complete the mastery number of each crops. One mastery plot is equivalent to 1 mastery. While mastering a crop you can earn some special rewards. Master each of a crop’s 3 levels for a special bonus

Here's the official statement:

"Congratulations! We're happy to introduce Crop Mastery! Now
harvesting a crop will earn you a point towards that crop's mastery level.
Master each of a crop's 3 levels for a special bonus!"