Soil Health Card: How to Read Your Soil Test (pH, N-P-K & More)

Updated 2026-07-10 · Crop guides

Your soil decides your yield ceiling — and guessing at fertiliser wastes money and hurts the crop. A soil test (the Soil Health Card in India) tells you exactly what your soil has and needs. Here is how to read it.

pH — the master dial

pH controls whether your crop can even absorb nutrients:

• 6.5–7.5 — ideal for most crops.
• Below 6 (acidic) — common in high-rainfall areas; add agricultural lime.
• Above 8 (alkaline/saline) — add gypsum and organic matter, and choose tolerant crops.

Organic carbon — your soil’s engine

Organic carbon (OC) reflects soil life and long-term fertility. Below ~0.5% is low. Raise it with compost/FYM, green manure, crop residue and reduced tillage — this single number quietly drives water-holding, structure and nutrient supply.

N, P, K — the big three

• Nitrogen (N) — leaf and stem growth; usually the most limiting, deficiency shows as pale/yellow older leaves.
• Phosphorus (P) — roots and flowering/grain set.
• Potassium (K) — water regulation, disease resistance and grain filling.

The card rates each as Low / Medium / High and gives a fertiliser recommendation. Follow the recommendation, not habit — applying what the soil already has in plenty is money burnt and can even cut yield.

Don’t forget micronutrients

Zinc, iron, boron and sulphur deficiencies are widespread and cause hidden yield loss even when N-P-K looks fine. If the card flags one (e.g. low zinc), correct it — a small, cheap dose often gives a big response.