On an average 1 kg N, P₂O₅, K₂O is added to increase grain yield by

Nitrogen, phosphorus, and potassium are macronutrient uptake by crop yields and crop residues by attaining high-input potential yields compared to that low-input yields, and the number of fertilizers applied.
On an average 1 kg of N, P₂O₅ and K₂O are added to increase grain yield by 10 kg.