Fertilizers

Wheat needs plenty of nitrogen, moderate phosphorus and some potassium — a common plan is DAP at sowing for phosphorus, MOP if the soil test calls for potash, and urea split into two or three top dressings (at crown-root initiation and tillering). Open the wheat crop portal or use the Fertilizer Finder above for a per-acre figure.

Urea is a straight nitrogen fertiliser (46% N) used mainly to push vegetative growth, top-dressed on a standing crop. DAP carries phosphorus (46%) plus some nitrogen (18%) and is applied at sowing, placed near the seed, because phosphorus does not move in the soil. You almost always need both — DAP at sowing, urea later.

It depends on the crop and, above all, on your soil test — that is exactly what the Soil Health Card is for. As a rough guide the Fertilizer Finder and the Fertilizer Calculator convert an ICAR-aligned dose into bags per acre, but a field test always beats a blanket rate and stops you paying for nutrients the soil already has.

You can apply them together at sowing, but do not mix and then store them — urea and DAP react over time and cake into a hard, unusable lump. Mix only what you will apply the same day.

N-P-K are the three nutrients crops need in the largest amounts: nitrogen (N) for leafy growth, phosphorus (P) for roots and flowering, potassium (K) for fruit, grain fill and stress tolerance. A fertiliser grade like 19:19:19 is the percentage of each in the bag.

Start with where the symptom is. Yellowing on the oldest leaves is usually nitrogen; a purple tinge is phosphorus; scorched leaf edges are potassium; pale bands on the newest leaves are zinc. The "Choose by problem" cards above link each symptom to a full diagnosis and its fix.

Flowering runs on phosphorus and potassium, not nitrogen — in fact too much nitrogen at this stage delays flowering and grows leaves instead. Make sure phosphorus was placed at sowing (DAP or SSP) and potassium is covered (MOP), and for poor flower or fruit set add boron, usually as a 0.1–0.2% borax foliar spray at the bud stage. On high-value fruit and vegetables a soluble grade like potassium nitrate (13:0:45) or NPK 19:19:19 through the leaf or drip helps at fruiting.

There is no single "yield" fertiliser — the biggest gains come from fixing whatever nutrient is actually short and getting the timing and placement right, not from adding more of what the soil already has. For most Indian fields the quiet wins are a balanced N-P-K based on a soil test, splitting nitrogen so the crop can use it, and correcting a hidden micronutrient shortage like zinc. A Soil Health Card test points you at the nutrient that will actually move your yield.

Both, split by nutrient. Phosphorus and potassium barely move in soil, so the full dose goes in at sowing as a basal, placed near the seed (DAP/SSP for phosphorus, MOP for potassium). Nitrogen leaches and volatilises, so only part goes in at sowing and the rest is top-dressed as urea at the crop’s peak-demand stages. The "Choose by growth stage" section above shows the four methods and when each is used.

Sometimes, but never assume it. Some water-soluble fertilisers and micronutrients tank-mix safely with certain pesticides, but many combinations react, clog the sprayer or scorch the crop. Check the pesticide label, do a small jar test first (mix a little and watch for curdling or sediment), and never mix zinc sulphate with a phosphate fertiliser. When in doubt, spray them separately.

It is a free government soil test that reports your field’s nitrogen, phosphorus, potassium and key micronutrient status and gives a crop-wise fertiliser recommendation. It matters because it stops you paying for nutrients the soil already has and flags the hidden shortage — often a micronutrient — that is actually capping your yield. It is the single best way to fertilise by need rather than by habit.

A complex fertiliser carries two or three nutrients chemically combined in every granule, shown as its N-P-K grade. Granular complexes like NPK 10:26:26 or 12:32:16 are basal fertilisers for phosphorus-and-potassium-hungry crops — one bag replaces separate DAP and MOP. Water-soluble complexes like NPK 19:19:19 are for foliar spraying and drip, not for broadcasting. A "straight" fertiliser (urea, MOP) carries only one nutrient; a complex is the convenience of a ready blend.

MOP (muriate of potash, 0-0-60) is the cheaper, standard choice and is fine for most field crops. SOP (sulphate of potash, 0-0-50) costs more but is chloride-free and adds sulphur, so it is worth it for chloride-sensitive, quality-sensitive crops — tobacco, some grapes, and many fruit and vegetables where taste, colour and shelf-life matter. For wheat, paddy or sugarcane, MOP is the sensible pick.

Fertigation needs fully water-soluble fertilisers so the drippers do not clog. The common ones are NPK 19:19:19 (and other soluble NPK grades), potassium nitrate (13:0:45), urea and calcium/magnesium/micronutrient solubles. Apply them in small, frequent doses through the season — "little and often" is the whole advantage of drip — and flush the lines with plain water afterwards. Do not put a granular field fertiliser like DAP through a drip system.

Sulphur matters for oilseeds and pulses — it builds oil and protein — and much of India’s soil is now short of it. The cheapest ways to add it are SSP (11% sulphur alongside its phosphorus), gypsum (18% sulphur plus calcium), and ammonium sulphate (24% sulphur with its nitrogen). Bentonite sulphur is a slower-release option. For mustard, groundnut and soybean, covering sulphur is often a bigger win than adding more N-P-K.