FMS enables you can have as many crops on any field as you like.  

You can even have multiple crops on a field in the same year.
All of the information you see on the Crop Records tab such as 
Crop Details, Seeding, Crop Insurance, etc pertains to the 
current crop for the selected field.

To view other screens, click on the appropriate link:
Field Details   Crop Records   Summer Fallow   Precipitation   Pictures
Crop Details   Seeding   Crop Insurance   Fertilizer   Chemical Application   
Crop Checking   Pests   Harvest