Explanation:
Fertilizers are chemically synthesized plant nutrients.
Nitrogen (N), Phosphorus (P) and Potassium (K) are macronutrients and are required in large amounts by plants. So, farmers use fertilizers in order to supply these nutrients. NPK 15:15:15 , NPK 20:20:20, NPK 15:30:15 are examples of fertilizers used to supply N, P, K to crops.
