Possible Clues:

• Agricultural system in formation of TUC, say?
• Practice of growing different things in a field in sequence
• French pig could be the product of this farm practice
• Farming technique for seasoned farmers (2 words)
• Common farming technique ... or a hint to solving this puzzle
• Element of farming activity that's more than half porcine?
• Method of raising farmland yields
• Cycling across the fields?
• Farm planting of different plants each year