- Home
- About Us
- Products
- News
- Exhibition
- Download
- Video
- Contact Us
Views: 0 Author: Site Editor Publish Time: 2026-04-29 Origin: Site
NPK compound fertilizer is a product that contains the three primary plant nutrients: nitrogen (N), phosphorus (P₂O₅), and potassium (K₂O). Unlike single‑nutrient fertilizers (e.g., urea), NPK compound delivers balanced nutrition in each granule or prill. Hebei Wangdalei Trading Co., LTD supplies NPK compound fertilizers in various ratios to meet crop and soil requirements. This article explains the composition, manufacturing methods, common ratios, and application principles.
An NPK compound fertilizer is defined as a fertilizer where each granule (or unit) contains all three primary nutrients in a fixed ratio. This is distinct from a physical blend (e.g., mixing urea + DAP + MOP), which can segregate during handling. Characteristics of true compound NPK include:
Homogeneity – Coefficient of variation (CV) of nutrient content across individual granules is typically <10%, compared to >25% for blends.
Uniform granule size – Usually 2–4 mm, ensuring even spreading.
Consistent physical properties – Hardness, moisture, and bulk density are controlled.
Customizable ratios – Common formulations include 15-15-15, 17-17-17, 20-20-20, and low‑chloride formulas for specific crops.
The three numbers on the label indicate the percentage by weight of:
Nitrogen (N)
Available phosphorus pentoxide (P₂O₅)
Soluble potassium oxide (K₂O)
For example, an NPK 15-15-15 bag contains 15% N, 15% P₂O₅, and 15% K₂O. The remaining 55% consists of filler, binder, moisture, and coating.
Three main processes produce true NPK compound fertilizer:
Steam granulation (rotary drum) – Powdered raw materials (urea, MAP, MOP, etc.) are fed into a rotating drum with steam (60–80°C) to form round granules. This is the most common method, accounting for about 65% of Chinese NPK production. Advantages: low dust, high granulation rate (85%), and smooth granules.
Slurry granulation – A liquid slurry of N, P, and K is sprayed into a granulator (spray dryer or fluidized bed). Produces very uniform, hollow granules. Common in Western Europe but less common in China due to higher energy cost.
Compaction (dry granulation) – Dry powders are pressed between rollers into flakes, then crushed and screened. No moisture added, so drying not required. Advantages: low moisture (<1.5%), suitable for moisture‑sensitive formulas.
| Ratio | Typical application | Application rate (kg/ha) |
|---|---|---|
| 15-15-15 | General purpose for field crops (corn, wheat, rice) | 250–400 |
| 17-17-17 | Higher concentration for similar balance | 200–350 |
| 20-20-20 | High concentration, often water‑soluble for fertigation | 150–250 |
| 12-12-17 | Low chloride (K from SOP) for potatoes, tobacco, citrus | 300–500 |
| 16-16-8 | Lower potassium for cereal crops with high soil K | 300–450 |
| 13-40-13 | High phosphorus for root establishment (starter fertilizer) | 100–200 |
| 10-26-26 | Balanced for oilseed rape (canola) | 200–350 |
Soil testing is recommended to select the optimal ratio. For example, a soil with high residual potassium but low phosphorus would benefit from a low‑K, high‑P ratio such as 20-20-0 (but that is an NP compound, not NPK).
Pre‑plant broadcast – Apply to soil surface and incorporate by disking or harrowing. This is the most common method for field crops. Example: For corn with target yield of 9 t/ha, apply 350 kg/ha of NPK 15-15-15.
Row or band application – Place fertilizer in a band 5 cm beside and 5 cm below the seed at planting. Use 100–200 kg/ha of a balanced NPK. Reduces total fertilizer use compared to broadcast.
Fertigation (drip or sprinkler) – Only fully water‑soluble NPK compounds (e.g., 19-19-19, 20-20-20) are suitable. Inject at a concentration of 0.5–2 g/L of water.
Top dressing – For rice, broadcast NPK onto flooded paddies. For wheat or barley, broadcast just before rain or irrigation. Avoid leaf contact to prevent burn.
NPK compound fertilizers are generally water‑soluble (80–95% solubility) and release nutrients within 1–2 weeks of application. However, the phosphorus component (P₂O₅) may fix to soil particles, reducing immediate availability. A 2023 study found that:
In a silt loam soil (pH 6.5), 70% of applied N from compound NPK was available within 14 days.
P availability was 40% at day 14, increasing to 55% at day 30 due to microbial activity.
K availability was 90% at day 7, as potassium is highly soluble and not strongly fixed.
For slow‑release requirements, coated NPK compounds (polymer‑sulfur coated) are available, with release durations of 60–120 days.
| Aspect | NPK compound | Physical blend |
|---|---|---|
| Nutrient uniformity | High (CV <10%) | Low (CV 25–40%) |
| Segregation during transport | None | Occurs, especially with differing granule sizes |
| Application accuracy | High | Variable |
| Cost per ton | Slightly higher (5–10%) | Lower |
| Suitability for precision ag | Excellent | Poor |
For large farms using precision spreaders, the extra cost of compound NPK is often offset by higher yield consistency.
Properly stored NPK compound fertilizer (in sealed bags, dry warehouse <30°C) retains its nutrient content for 24 months. However, physical quality degrades:
After 12 months, caking tendency increases by 10–15%.
After 24 months, crushing strength may decrease by 20% due to recrystallization.
Quality indicators to check before use:
Appearance: Free‑flowing granules, no lumps.
Smell: No ammonia odor (indicates nitrogen loss).
Color: Uniform (varies by formula; 15-15-15 is typically grey or pink due to MOP).
Dissolution test: Place 10 g in 100 mL water at 25°C. Stir for 5 minutes. >80% should dissolve (for standard grade).
Hebei Wangdalei Trading Co., LTD supplies NPK compound fertilizer in the following product lines:
High‑concentration series – 15-15-15, 17-17-17, 20-20-20 (granular, 2–4 mm)
Specialty series – 12-12-17 (low chloride, SOP‑based), 10-26-26, 13-40-13
Water‑soluble series – 19-19-19, 20-20-20 (100% soluble, for fertigation)
Slow‑release coated NPK – Polymer‑coated, release 60–90 days (custom)
Each shipment includes a batch certificate with analytical data, moisture level, granule size distribution, and crushing strength. Third‑party inspection (SGS, Bureau Veritas) is available.
NPK compound fertilizer provides balanced, homogeneous nutrition for crops. Its uniform granule composition and consistent physical properties make it suitable for mechanized precision agriculture. Buyers should select the ratio based on soil tests and crop needs. Hebei Wangdalei Trading Co., LTD offers a range of NPK compound fertilizers with documented quality, serving both conventional and specialty farming systems.
