NPK ratio
Topic: Land Reforms, the Green Revolution and Farm Subsidies · NCERT: Beyond NCERT
Meaning
The NPK ratio is the ratio of nitrogen (N), phosphorus (P) and potassium (K) applied to the soil. The ideal ratio is about 4:2:1. India's use is heavily skewed towards nitrogen because urea, the main nitrogen fertiliser, is sold cheaply at a price fixed by the government. Phosphorus (P) and potassium (K) fertilisers fall under the Nutrient Based Subsidy (NBS, 2010) and cost more. This imbalance harms soil health and causes micronutrient deficiencies.
Example
In the rice-wheat belt, farmers apply a lot of cheap urea but little DAP or MOP. Over time this has caused zinc and sulphur deficiencies, and yields respond less to extra fertiliser. Soil Health Cards (2015) give each field a fertiliser recommendation to correct this.
Don't confuse with
- Nutrient Based Subsidy (NBS): NBS is a fixed subsidy per kg of nutrient for P and K fertilisers. Urea is outside NBS. The NPK ratio is a measure of how much of each nutrient is used, not a subsidy scheme.