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Nitrogen fertilizers with sulfur

Ammonium Sulphate AS 21

Nitrogenous fertilizer N(S) 21-(24)

Trade name: Ammonium Sulphate AS 21
Chemical name: ammonium sulphate
PKWiU: 20. 15. 32. 0
CN: 31 02 21 00

Grupa Azoty S.A. (Tarnów)

Crystalline fertilizer, cream to grey-beige in colour, without permanent caking characteristics.Ammonium Sulphate AS 21 includes 21% of nitrogen (N) in nitrates and 24% of sulphur (S) [which constitutes 60% calculated per sulphur trioxide (SO3)], soluble in water, in sulphate form.

Intended use and applicationSee more
Ammonium Sulphate AS 21, as a spring-time fertilizer, may be used under all cultivated plants: winter and spring crops, economic and root plants, on grassland and in cultivation of vegetables and fruit cultures. It is particularly recommended for early-spring fertilization of crucifer plants (rape, oil-yielding rape, mustard, cabbage, cauliflower, cabbage turnip), leguminous plants, potato, onion, leek, garlic and horseradish. It is recommended that Ammonium Sulphate AS 21 be used first prior to sowing or crop treatment, to be mixed with soil or for top dressing before expected rain.
On account of its hygroscopicity, Ammonium Sulphate AS 21 may be mixed immediately before spreading with ammonium nitrate, PODLIDAP®, POLIFOSKA® and POLIMAG® S, and with potash salt, provided that the fertilizers are dry.
AdvantagesSee more
Ammonia nitrogen is not washed out of the soil, is absorbed by plants slowly, enhances plant rooting, supports absorption of phosphorus and limits excess absorption of potassium. An advantage of this fertilizer is the possibility of providing plants with nitrogen and sulphur in spring. The high sulphate sulphur content, perfectly soluble in water, increases the immunity of plants and provides them with sulphur early in spring growth. It is important to remember that the highest, and ever more common, deficiencies of sulphur in soil occur in early spring, after it has been washed out of the soil in winter.
Using Ammonium Sulphate AS 21 results in good plant rooting, increases plant growth dynamism in early phases of development and improves strength, and is thus a factor in increase in yield and improvement in its quality.
Packaging and transportSee more
Ammonium Sulphate AS 21 is packaged in:
  • 25 or 50 kg ± 1% polyethylene bags with overprint;
  • Flexible containers at 500 kg ± 1% or more, the so-called big-bags; 
  • Bulk.
The fertilizer must be transported while protected against water, rainfall, direct sunlight and damage to the packaging.
Ammonium Sulphate AS 21 is not classified, i.e. it is not considered a hazardous material according to the UN Orange Book and international transport codes, for example RID (railway transport), ADR (road transport) and IMDG (sea transport).
With regard to transportation using the road vehicles of the recipient or of a carrier acting on the direct instructions of the recipient, it is the recipient or the carrier who is responsible for any deterioration in the quality of the fertilizer.
StorageSee more
Ammonium Sulphate AS 21 is a highly hygroscopic product and should be stored in clean and dry warehouse buildings with non-flammable floors ensuring good insulation against moisture.
Ammonium Sulphate AS 21 should be protected against:
  • Water and rainfall;
  • Direct sunlight;
  • Mechanical damage to packages;
  • Heating above 30°C.
Ammonium Sulphate AS 21 must not be stored in an open space owing to its low resistance to temperature changes and the impact of moisture and heat.
Polyethylene bags with overprint of a net content of 25 or 50 kg should be stored in horizontal layers, in 12 layers at the most. Fertilizer in flexible containers of less than 500 kg in weight may be stored in piles of up to three layers, and in two layers if over 500 kg. In the case of pallet storage, loading units should be made of one-layer piles.
PrecautionsSee more

If irritation occurs, wash skin and eyes with plenty of water. Dust masks and safety goggles are recommended. If swallowed accidentally, seek medical advice. Nontoxic, odourless, non-flammable fertilizer.

Support and consultingSee more

Aiming to provide the highest standards of customer service, the Grupa Azoty offers professional consulting, information support for farmers and food producers.

Support includesSee more


  • Client support with technical knowledge, that is, consulting in fertilizer use
  • Resolution of problems reported by the client (dosage, chemical composition of fertilizers, mechanisms of effect on cultivated plants and elements of the natural environment)
  • Provision of information on distribution centres in the country
  • Information on the current fertilizer product range of the Grupa Azoty


Paweł Franczyk - Director of the Bureau of Export Fertilizer
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