eli5 : If plants can make their food with water and carbon dioxide using photosynthesis why do they need manure and fertilisers ?

Question

eli5 : If plants can make their food with water and carbon dioxide using photosynthesis why do they need manure and fertilisers ?

In: Biology

Answer 1

Photosynthesis is like a factory. A factory needs raw materials to turn into finished products. Without them, a factory is useless.
Plants take nutrients in from soil and fertilizer, and the photosynthesis factory turns them into things the plant needs.