Ammonium Sulphate Granular – Application & Fertilization Guide

I. Product Overview

Ammonium Sulphate Granular is a fast-acting ammonium nitrogen fertilizer with a nitrogen content of 20%–21%. It is chemically stable, has uniform particle size, and excellent water solubility. The product is suitable for most crops and various application methods.

Key Features:

• Rapid nitrogen availability

• Uniform granules, suitable for mechanical application

• Non-hygroscopic, free-flowing, and easy to store

• Contains sulphur, promoting protein synthesis

• Safe for chlorine-sensitive crops

Main Applications:

• Direct soil application

• Raw material for blended and compound fertilizers

• Foliar fertilization

• Seed treatment

II. Application Methods and Instructions

1️⃣ Direct Application (Primary Use)

Direct application is the most common method, suitable for both basal and topdressing fertilization of field crops and cash crops.

General Principle:
Deep placement, soil covering, and keeping fertilizer away from roots to avoid crop injury.

(1) Basal Application

• Method: Evenly broadcast during land preparation and plow into the soil at a depth of 10–15 cm.

• Recommended Dosage:

  • Field crops (rice, wheat, maize): 15–25 kg per mu

  • Cash crops (vegetables, fruit trees): 20–30 kg per mu

• Acidic soils: Apply 50–100 kg quicklime per mu to prevent soil acidification.

(2) Topdressing

• Methods:

  • Furrow application (5–8 cm deep)

  • Hole application beside plants (5–10 cm away from roots)

• Application timing: Peak nitrogen demand stages

  • Rice: tillering stage

  • Maize: tasseling stage

• Dosage: 10–15 kg per mu, applied 1–2 times

• Note: Cover with soil after application to avoid root burn.

(3) Fertigation

• Fully dissolve the granules in water and apply evenly through irrigation systems.

• Suitable for topdressing to improve nutrient uptake efficiency.

2️⃣ Blended and Compound Fertilizer Production

Due to its stable nitrogen form and non-hygroscopic property, ammonium sulphate granular is an ideal raw material for fertilizer blending.

(1) Industrial Compound Fertilizer Production

• Can be blended with:

  • Phosphate fertilizers (MAP / DAP)

  • Potash fertilizers (Potassium chloride or Potassium sulphate)

• Suitable for producing customized NPK compound fertilizers for various crops.

(2) On-Farm Fertilizer Blending

• Can be mixed with:

  • Well-decomposed organic fertilizer (improves soil structure and reduces acidification)

  • Single superphosphate (supplements phosphorus)

• Widely used for vegetables, fruits, tobacco, and other cash crops.

⚠ Important Notice:

• Do NOT mix directly with alkaline fertilizers (wood ash, quicklime, calcium-magnesium phosphate), as this causes nitrogen loss through volatilization.

• If both are required, apply separately with an interval of 7–10 days.

3️⃣ Foliar Fertilization (Emergency Nitrogen Supply)

Foliar spraying provides rapid nitrogen supplementation when root absorption is weak or nitrogen deficiency symptoms occur.

• Solution concentration: 0.5%–1%
  (0.5–1 kg ammonium sulphate per 100 kg water)

• Application rate: 50–60 kg solution per mu

• Spraying time: Early morning or late afternoon; avoid high temperature and strong sunlight.

• Frequency: 2 consecutive applications at 7–10 day intervals

• Suitable crops: Rice, wheat, vegetables, fruit trees, etc.

⚠ Precautions:

• Do not exceed 1% concentration to avoid leaf scorch.

• Do not mix with alkaline pesticides such as Bordeaux mixture.

4️⃣ Seed Treatment (Soaking and Coating)

Ammonium sulphate can be used for seed treatment to provide readily available nitrogen during early seedling growth.

(1) Seed Soaking

• Solution concentration: 0.2%–0.3%

• Soaking duration:

  • Wheat & rice: 6–8 hours

  • Maize: 4–6 hours

• Dry seeds after soaking before sowing.

(2) Seed Coating

• Moisten seeds lightly with water.

• Add ammonium sulphate powder at 0.5%–1% of seed weight.

• Mix thoroughly and sow immediately.

⚠ Notes:

• Strictly control concentration.

• Coated seeds should not be stored and must be sown on the same day.

• Not recommended for leguminous crops.

III. General Recommendations and Precautions

✔ Crop Compatibility

• Suitable for rice, wheat, maize, cotton, vegetables, and fruit trees.

• Safe for chlorine-sensitive crops such as tobacco, tea, potatoes, and sugarcane.

• Use with caution on legumes (soybean, peanut) to avoid inhibiting biological nitrogen fixation.

🌱 Soil Compatibility

• Best suited for neutral to slightly alkaline soils.

• Acidic soils require lime application.

• Use cautiously on saline-alkali soils to prevent salt accumulation.

🔄 Long-Term Use Recommendations

• Avoid long-term single application.

• Rotate with other nitrogen fertilizers such as urea or ammonium bicarbonate.

• Combine with phosphorus, potassium, and organic fertilizers to maintain nutrient balance.

📦 Storage and Transportation

• Store in a dry, well-ventilated place.

• Protect from moisture and rain.

• Avoid package damage during transportation.

• Do not store or transport together with alkaline substances.