Bio-fertilizers are preparations that contain carefully selected, highly active living microorganisms. Through their natural activity in the soil, these microbes generate essential nutrients for the soil and crops, helping plants grow better.
When bio-fertilizers are applied, nitrogen-fixing and phosphorus-solubilizing microbes act like tiny “fertilizer factories” in the soil, producing natural nitrogen and phosphorus to feed plants directly. Using bio-fertilizers can replace 50 %–100 % of chemical nitrogen and phosphate fertilizers, depending on the crop. They also reduce nitrate (NO₃) residues in produce and lower the risk of chemical contamination. Compared with chemical fertilizers—especially urea—bio-fertilizers are less expensive and often deliver higher overall economic efficiency.
Bio-fertilizers can be used on virtually all crops—fruit trees, tea, rice, maize, vegetables, even ornamental plants. Because they release nutrients more slowly than chemical fertilizers, they are mainly applied as a basal (pre-planting) dressing for short-season crops. For seasonal crops, apply a top-up after each harvest. For fruit trees, apply twice a year during the spring rains (March–April) and the late-summer rains (July–August) to take advantage of soil moisture for optimal microbial activity.
Application guidelines (typical rates):
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Fruit trees & other perennials: Spread 1–2 kg per tree in a ring under the canopy after lightly hoeing the soil; cover with a thin layer of soil.
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Tea bushes: 0.2–0.3 kg per plant, in the furrow between rows.
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Rice: 10 kg per northern sào* can cut urea and phosphate use by 50 % (apply as basal and after the first weeding).
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Seedlings (rice nursery): Mix 2 kg per sào into the seedbed before sowing.
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Maize: Before sowing, apply 10 kg per sào plus 50 % of the recommended urea and phosphate. When plants have 3–4 leaves, apply another 10 kg per sào and hill up soil.
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Vegetables: Basal application 10–15 kg per sào can replace 50–100 % of urea and phosphate—about 50 % for leafy vegetables, 70 % for root crops, 100 % for fruiting vegetables.
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Potted ornamentals: Mix 1 kg bio-fertilizer with 2–3 kg fine soil to feed about 10 pots; keep soil moist for best effect.
(*1 northern sào ≈ 360 m².)
Best practices:
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Reduce chemical fertilizer use while applying bio-fertilizers.
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Because they contain live microbes, store in a cool, airy place: about 1 month in summer, 1.5 months in winter.
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Keep soil adequately moist so microbes stay active.
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For acidic soils, apply lime 2–3 days before using bio-fertilizer.
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Do not mix bio-fertilizers with chemical fertilizers or wood ash, which can kill the microbes.
Used correctly, bio-fertilizers not only improve soil fertility and crop yield but also lower costs and make farm products safer for consumers.