Answer
Copper: 4-30g
Zinc: 15-100g
Potassium: 5-60kg
Iron: 25-300g
Work Step by Step
1 ppm=1 mg/kg. With 1000 kg of potatoes, each ppm gives a gram of nutrient at the end of the calculation (1mg/kgx1000kg=1000mg=1g). 1% of 1000kg=10kg, so for part C., just work proportionally.