Granular Ammonium Sulfate (21-0-0-24S) combines high nitrogen content with essential sulfur in a form that is easy to handle, store, and apply. Engineered for uniform spreading and excellent soil incorporation, our premium granules deliver 21% ammonium nitrogen and 24% sulfate sulfur to crops that demand both rapid growth and sustained quality. For growers seeking cost‑effective, chloride‑free nutrition with minimal environmental loss, granular ammonium sulfate is the trusted choice.

I. Why Granular Form Matters

Uniform Particle Size for Precision Application
Our granules are manufactured to a narrow 2–4 mm range, ensuring consistent flow through all types of broadcast spreaders, air seeders, and fertilizer blenders. The uniform size eliminates segregation during blending with other granular products and guarantees an even distribution pattern across the field.

Dust‑Free and Free‑Flowing
Special anti‑dust conditioning reduces airborne particles, improving operator safety and minimizing product loss on windy days. The granules are free‑flowing even after months of storage, with a hardness of ≥50 N that resists crushing in handling and application.

Ideal for Blending
Because the granules are close in density to other common fertilizer materials (MAP, DAP, potash), they remain well‑mixed and do not stratify during transport. This makes granular ammonium sulfate the preferred source of sulfur in bulk blends for custom applicators.

II. Core Agronomic Benefits

Dual Nutrient Supply in One Product
Provides 21% nitrogen in the ammonium form, which is held by soil colloids and resists leaching, and 24% sulfur in the sulfate form, immediately available for plant uptake. This combination is essential for crops with high sulfur requirements: canola, onions, cruciferous vegetables, and forages.

Physiological Acidity for Alkaline Soils
As an acidifying fertilizer, granular ammonium sulfate lowers soil pH in calcareous and high‑pH soils. This releases locked‑up phosphorus and micronutrients (iron, zinc, manganese), improving overall fertility. On neutral soils, the acidifying effect is minimal when used at recommended rates.

Low Volatility, High Efficiency
Compared to urea, ammonium sulfate has very low ammonia volatilization potential, even when surface‑applied without incorporation. More of the applied nitrogen stays in the soil for crop uptake, resulting in higher nitrogen use efficiency (NUE) and lower environmental impact.

Chloride‑Free and Crop‑Safe
Contains no chloride, making it safe for sensitive crops including tobacco, potatoes, fruit trees, berries, and greenhouse vegetables. It also has a low salt index, reducing the risk of seed or root injury when placed near the row.

III. Application Guidelines

Soil Application – Broadcast

• Rate: 200–500 kg per hectare, depending on crop and soil sulfur status.
• Timing: Pre‑plant or at early vegetative stages; light incorporation or irrigation within 24 hours maximizes efficiency.
• Field crops: 300–400 kg/ha as a top‑dress for wheat and barley at tillering.

Band Application (Starter Fertilizer)

• Rate: 50–150 kg per hectare placed 5 cm below and 5 cm beside the seed.
• For corn: 100 kg/ha in the band provides early sulfur for stalk strength and kernel fill.
• For canola: 50–75 kg/ha in the band meets high sulfur demand for oil synthesis.

Top‑Dressing for Cereals and Oilseeds

• Wheat: 200–300 kg/ha at jointing to boot stage. Increases grain protein and test weight.
• Canola: 250–350 kg/ha split at rosette and early flowering (sulfur before flowering is critical).
• Rice: 200–300 kg/ha in flooded paddies; the ammonium form is stable under anaerobic conditions.

Fertigation (Fine Granules or Dissolved)

• While standard granules are designed for dry application, soluble grades of ammonium sulfate can be dissolved (solubility 750 g/L at 20°C). Use in drip systems at 50–100 kg/ha per application, ensuring thorough mixing.

Turf and Specialty Crops

• Golf greens and sports turf: Apply 15–30 g/m² (150–300 kg/ha) two to three times per growing season to maintain deep color and density.
• Onions and garlic: Side‑dress 150–200 kg/ha at bulb initiation.

IV. Technical Specifications

Chemical Properties

• Total nitrogen (N): 21.0% minimum (ammonical)
• Sulfur (S): 24.0% minimum (as SO₄)
• Free acid (as H₂SO₄): ≤ 0.05%
• Moisture: ≤ 0.5%

Physical Properties

• Granule size: 2–4 mm (90% within range)
• Crush strength: ≥ 50 N
• Bulk density: 1000–1100 kg/m³
• Dust content: < 0.1%
• Solubility: 750 g/L at 20°C (fully soluble)

Quality Standards

• Heavy metals: Cd ≤ 1 ppm, Pb ≤ 5 ppm, As ≤ 1 ppm
• Chloride (Cl): ≤ 0.01%
• Insoluble matter: ≤ 0.05%

V. Crop‑Specific Benefits

Wheat and Barley
Sulfur is required for the formation of gluten proteins. Granular ammonium sulfate applied at 300 kg/ha before stem elongation increases grain protein by 1–2% and improves milling and baking quality. Test weight increases by 2–3 kg/hL.

Canola
Canola has one of the highest sulfur demands among field crops. A total of 350–400 kg/ha of 21-0-0-24S, split between pre‑plant and rosette, increases oil content by 3–6% and seed yield by 15–25% in sulfur‑deficient soils.

Corn (Maize)
Sulfur deficiency shows as interveinal chlorosis on younger leaves. Banding 100–150 kg/ha of granular ammonium sulfate at planting supplies sulfur for protein synthesis and kernel development, often increasing yield by 10–15%.

Potatoes
Apply 250–350 kg/ha pre‑plant or at emergence. The sulfur component improves specific gravity, reduces internal brown spot, and enhances processing quality for french fries and chips.

Onions and Garlic
Side‑dress with 150–250 kg/ha during bulb initiation. Sulfur is a precursor of allicin and other flavor compounds, significantly improving pungency, storage life, and market value.

Forage and Pasture
Broadcast 150–250 kg/ha after each cutting or grazing. Sulfur boosts crude protein content and dry matter yield, while the ammonium nitrogen provides quick regrowth. For grass‑legume mixes, the ammonium form encourages legume nodulation.

VI. Environmental and Handling Benefits

Reduced Ammonia Loss
Ammonium sulfate’s low pH and ammonium form keep nitrogen in the soil. In side‑by‑side trials, ammonia volatilization from surface‑applied granular ammonium sulfate was less than 5%, compared to 20–25% for urea. This translates to more nitrogen per dollar.

Minimal Leaching Potential
The ammonium cation is positively charged and adsorbs to clay and organic matter. Unlike nitrate‑based fertilizers, the nitrogen does not readily leach following heavy rain or irrigation. This makes granular ammonium sulfate ideal for sandy soils and high‑rainfall regions.

Easy Storage and Handling
Our granules are coated with a non‑hygroscopic agent that resists caking for up to 24 months. Bags can be stacked without fusing, and the product flows freely through all types of spreader mechanisms.

Safe for the Environment
With low heavy metal content and no chloride, granular ammonium sulfate is approved for use in organic systems (when sourced from appropriate raw materials) and in environmentally sensitive watersheds.

VII. Quality Assurance and Certifications

Our granular ammonium sulfate is produced in ISO 9001:2015 and ISO 14001:2015 certified facilities. Each batch is analyzed for nutrient content, granule size distribution, crush strength, and heavy metals. Certificates of Analysis accompany every shipment. Anti‑dust and anti‑caking treatments are applied at the manufacturer’s standard.

VIII. Why Choose Our Granular Ammonium Sulfate

Consistent Performance
Uniform granule size and high hardness ensure accurate spreading and even crop response across the entire field.

Superior Logistics
Available in 25 kg bags, 1‑ton FIBCs, and bulk vessel shipments. Multiple warehouse locations across the Americas, Europe, and Asia guarantee short lead times.

Technical Support
Our agronomists help you determine the correct rate and timing, interpret soil sulfur tests, and integrate granular ammonium sulfate into your overall fertility plan.

IX. Ordering and Contact

Product Availability

• 25 kg multilayer moisture‑proof bags
• 50 kg woven sacks
• 1000 kg bulk bags (FIBC)
• Bulk truck or container loads