Possible Clues:

• Conclude Panama, say, is not productive
• Like poor soil
• It's not productive to make a deduction on old-fashioned hat
• Sounds as if it's a baron to conclude that one is on the roof
• Reason that hat needed for desert
• So can't father gather hat?
• Barren
• Conclude shingle is unproductive
• Deduce that one component of Scrabble is not productive
• Presume oriental settled back to be unproductive