Best Fertilizer for Soybean in India
Soybean is a major kharif oilseed and a legume that fixes nitrogen through Rhizobium nodules. It needs only a small starter dose of nitrogen but responds strongly to phosphorus, potash and s
Overview
Soybean is a major kharif oilseed and a legume that fixes nitrogen through Rhizobium nodules. It needs only a small starter dose of nitrogen but responds strongly to phosphorus, potash and sulphur. As an oilseed, sulphur is especially important because it raises oil content and yield. A good Rhizobium and PSB seed treatment supplies much of the nitrogen and saves fertiliser, while heavy urea reduces nodulation. Almost all fertiliser is given as a basal dose at sowing. Soybean also enriches the soil with nitrogen for the next crop. Always base your dose on a soil test or Soil Health Card and confirm local rates with your KVK, as soils differ widely.
Recommended NPK dose for Soybean
The IISR recommended dose is 20 to 25 kg N, 60 kg P2O5, 40 kg K2O and 20 kg sulphur per hectare, which is roughly 8 to 10 kg N, 24 kg P2O5, 16 kg K2O and 8 kg sulphur per acre. Note the low nitrogen and high phosphorus typical of legumes, plus sulphur for the oilseed. This can be met by about 50 kg DAP plus 27 kg MOP plus 10 kg bentonite sulphur per acre, or single super phosphate which also supplies sulphur. These are general ranges only. Get a soil test or Soil Health Card done and follow the dose advised by your KVK.
Application schedule
Soybean needs all its fertiliser as a single basal dose at sowing. Apply the full nitrogen, phosphorus, potash and sulphur in the seed furrow or just below the seed before sowing, so the young roots reach it quickly. No nitrogen top dressing is required because nodules supply nitrogen through the season. If the crop looks pale at flowering on poor soils, a 2 percent urea or DAP foliar spray at flowering and pod-filling can help, but avoid broadcasting heavy urea which suppresses nodulation.
Organic & bio-fertilizers
Mix 4 to 5 tonnes of well rotted FYM or compost per acre, about 10 tonnes per hectare, into the soil before sowing. Treat seed first with fungicide, then with soybean-specific Rhizobium at 5 g per kg seed plus PSB at 5 g per kg seed, dry in shade and sow the same day. Soybean Rhizobium is crop-specific, so use the right culture. This supplies much of the nitrogen and unlocks soil phosphorus. Vermicompost at 1 to 2 tonnes per acre can replace part of the FYM.
Micronutrients & deficiency signs
Sulphur is the key nutrient for soybean as an oilseed; apply about 8 kg per acre through gypsum, bentonite sulphur or single super phosphate to raise oil content and yield. Zinc deficiency, seen as yellowing between veins of upper leaves and stunted growth, is corrected with 10 kg zinc sulphate per acre or a 0.5 percent spray. Iron and manganese deficiencies appear as yellow new leaves in alkaline soils; spray 0.5 percent ferrous or manganese sulphate. Apply boron only if a soil test confirms a shortage.
Tips & cautions
Use the correct soybean-specific Rhizobium and treat seed with fungicide first, then Rhizobium and PSB, sowing the same day. Do not overuse nitrogen; it suppresses nodulation. Never miss sulphur, as it directly raises oil content. Place phosphorus near the seed for better uptake. Avoid waterlogging which kills nodules. Test your soil every two to three years and follow your KVK for the local dose.
These are general recommendations. For the exact dose, follow your Soil Health Card / soil test and local KVK, and avoid over-applying urea.
FAQs
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