Nutrient Composition & Chemical Properties
NPK 13:40:13 is classified under the Fertilizer Control Order (FCO) as a 100% water-soluble complex fertilizer. The elevated phosphorus component (40% P2O5) provides immediately available orthophosphate directly to active root zones.
Its balanced presence of nitrogen (13% N) supports vegetative vigor, while potassium (13% K2O) regulates stomatal conductance and builds disease resistance during early development.
- Total Nitrogen (N): 13% w/w minimum (balanced nitrate and ammoniacal nitrogen)
- Available Phosphate (P2O5): 40% w/w minimum in completely soluble form
- Water-Soluble Potash (K2O): 13% w/w minimum derived from high-purity sources
- Solubility: Highly soluble in water without leaving insoluble particulate residues
Target Crop Stages & Agronomic Benefits
Because phosphorus is relatively immobile in soil, foliar or fertigation applications of NPK 13:40:13 bypass soil lockup in alkaline or acidic soils, ensuring rapid nutrient translocation.
It is particularly beneficial during the early seedling establishment, vegetative branching, and pre-flowering stages in crops such as cotton, sugarcane, pulses, chillies, tomatoes, and fruit orchards.
- Root Architecture: Stimulates deep taproot and lateral feeder root expansion in young transplants
- Tillering & Branching: Enhances tiller counts in wheat, paddy, and primary branching in legumes
- Floral Initiation: Provides high-energy phosphate needed for cell division and uniform floral bud set
- Cold & Drought Resistance: Enhances plant energy reserves (ATP synthesis) to withstand early-season climatic stresses
Application Guidelines & Tank-Mix Rules
For foliar spray, dissolve at standard dilution rates and apply thoroughly during cool hours. For drip fertigation, inject through a Venturi injector or fertigation tank following routine system filtration.
Do not mix water-soluble phosphorus fertilizers with calcium or magnesium fertilizers in concentrated stock tanks, as insoluble calcium phosphate precipitates can clog drip emitters.
- Drip Fertigation: Inject through drip systems, flushing with clean water for 15 minutes post-injection
- Foliar Spray: Apply as a fine mist; avoid spraying during midday heat to prevent leaf margin scorch
- Mixing Caution: Do not tank-mix with Calcium Nitrate in the same concentrated stock solution
- Storage: Keep bags tightly sealed in a dry, ventilated shed to prevent moisture absorption and caking
Official source
Check the latest rules, benefits and forms here. KisanPe is an independent platform and is not a government website.
Department of Fertilizers, Ministry of Chemicals and Fertilizers ↗Related on KisanPe
Common questions
What makes NPK 13:40:13 especially effective during early crop stages?
Its 40% soluble phosphorus content delivers readily available phosphate that accelerates root expansion, tillering, and energy transport during initial establishment.
Can NPK 13:40:13 be applied through drip irrigation?
Yes, it is a 100% water-soluble formulation specifically manufactured for drip fertigation and foliar spraying without clogging drip emitters.
Why should NPK 13:40:13 not be mixed with Calcium Nitrate?
Concentrated mixtures of soluble phosphate and soluble calcium form insoluble calcium phosphate precipitate, which clogs drip drippers and reduces nutrient availability.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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