Possible Clues:

• Fertiliser chemical
• Fool in front of judge? Take that with a pinch of salt perhaps!
• Treat in producing fertiliser
• Fertiliser can's rising cost
• Local fool in front of judge produced fertiliser
• Fertiliser cost is lower than man heard
• Measure of a quibbler’s output?
• Fertiliser can's tipped controlled amount
• Salt last of cheese pie at home, served up
• Acid salt