Desiccation is necessary to harvest crops in order to avoid wet/snowy seasons.  Farmers will lose their entire crop if it stays to wet or freezes.  The crop needs to be killed/dried for storage and for better combining.  90% of the crop you see never goes to a table, it goes to animal feed or in the case of corn, ethanol production.  

Millennial farmer or Larson farms on YouTube dispel alot of questions around agriculture and farming.  Great resources and entertainment.