Which one of the following crops would require a minimum quantity of NPK or urea for its proper growth?
Cabbage, sugarcane, wheat, soyabean.

17 Patches of white powdery material are seen on the bags of wheat stored in a godown. What does it indicate? 18 State the factors, which have helped us to raise food production. 20 Name one biotic and abiotic factor, which is responsible for the damage of stored food grains. 21 A farmer grows maize crop in a field year after year. He finds that the yield becomes low. Give one possible reason for it.