AMMONIUM SULPHATE, ONE OF THE MOST PRACTICAL NITROGEN FERTILISERS TO USE

Ammonium sulphate is not just a fertiliser used in agriculture.
It is an industrial component also used as a flocculant, which is a substance that encourages flocculation, i.e. the combination or aggregation of suspended solid particles.
The flocculation process involves destabilising colloidal particles by adding the flocculant.

It also has all these industrial applications:

• Acid solution purifier.
• Glyphosate enhancer.
• Flame retardant.
• Food additive.
• Protein purification through fractional precipitation.

 

WHAT IS AMMONIUM SULPHATE?

Ammonium sulphate is a salt formed by the reaction between Ammonia and Sulphuric acid. Commercially, it can be found in white to beige crystals or granules.
Its content is as follows:

• 21% Nitrogen
  
• 60% Sulphur
  

It is the most accessible source of low-concentration Nitrogen, is widely used in agriculture, and is also a relevant component in the production of balanced fertilisation formulas.
It is widely applied directly to the soil as a single product
, is an excellent source of fertilisation
in crops which extract large quantities of sulphur from the soil,
such as forage crops, vegetables (cruciferous vegetables, onions and garlic), cereals (wheat and barley) and grasses (maize, sorghum and sugar cane), among others.

It mainly contains Ammonium (NH
₄⁺) and Sulphate (SO
_4-2), and it is an acid pH product that is recommended for application in limestone and alkaline soils due to its strong acidifying effect.
Its use as a fertiliser is due to the fact that the need for sulphur is closely related to the amount of nitrogen available for the plant. Therefore, Ammonium Sulphate provides a balanced supply of both nutrients.

In conventional agriculture, it is still used en masse, especially for less profitable crops and as an important source of Nitrogen accompanied by Sulphur, a precursor in its assimilation.
It is therefore not an organic fertiliser, as its process is obtained through synthetic transformations and, as such, is not covered by European organic farming regulations.

In the field, it is known as a good fertiliser used in both extensive and intensive crops with a dual action, as it provides two macronutrients added to its Sulphur content that promotes the physical and chemical conditions of the crop soils.

 

Optimising the dose and application to crops in the soil, Ammonium Sulphate is a very good source of supply of this element, and is easy to mix and use.
The form of Ammonium is usually quickly assimilated by crops, although in large volumes it can become phytotoxic to the plant.
In fact, in hydroponics, its use is limited to a maximum of 15-20% of the total fraction of Nitrogen, the remaining being 80-85% Nitric Nitrogen.

Inorganic soil sulphur is absorbed by plants mainly as anion Sulphate and, due to its negative charge, it is not attracted by soil clays and inorganic colloids;
Sulphur remains in the soil solution, moving with the water flow and, therefore, is easily leachable
. In some soils, this leaching accumulates Sulphur in the subsoil, making it usable by deep-rooted crops.
The risk of leaching is higher in sandy soils than in clay-textured soils.

Soils with low organic matter content (<2%) commonly have Sulphur deficiencies, and every one percent of organic matter releases approximately 6 kg of it per ha per year.

In plants, Nitrogen and Sulphur have a very close relationship in their nutritional role.
This is because both nutrients are constituents of the 5 proteins (amino acids) and are associated with the formation of chlorophyll (involved in the photosynthesis process).

 

OBTAINING PROCESS

The obtaining of Ammonium Sulphate as an industrial product is the transformation of Gaseous Ammonia (NH₃), mixed with water vapour to create saturation, and the incorporation of Sulphuric Acid.

This controlled reaction is transformed into the mixture of Sulphur (SO₄) and Ammonium (NH₄), which, because it is attacked with an acid, one more Hydrogen (H) is added to the formula.

 

CHEMICAL PROPERTIES

All the Nitrogen in this fertiliser is presented in ammoniacal form.
Although it is highly digestible by the plant, it should preferably be absorbed in nitric form.

Its behaviour in soil is good and, because it has a positive charge, it is fixed in the clay-humus complex and does not leach so much to deep fields (as the nitric form does).

The presence of nitrifying microorganisms (nitrobacter and nitrosomonas, among others) facilitates its transformation to nitric.
As it has an acid reaction, it is used to acidify soils with an alkaline pH and a high presence of non-soluble Calciums and Magnesiums.
In addition, the Sulphur incorporated into the fertiliser improves the availability of Nitrogen and has a synergistic effect in its assimilation.

 

TYPES OF AMMONIUM SULPHATE

1. Powdered Ammonium Sulphate: Its presentation is in solid form, but in easily soluble powder.
   Its application is very frequent and is suitable to prepare liquid solutions in Fertirrigation.
   Because it is highly soluble, this fertiliser must always be applied as top dressing, i.e. when we already have crops planted.
2. Liquid Ammonium Sulphate: This is highly soluble, but less so than other fertilisers such as Ammonium Nitrate.
   There are cases in which farmers prefer to work with already soluble liquid formulas of Ammonium Sulphate.
   A concentrated formula would be to dilute up to 40% of the fertiliser for a Nitrogen concentration of 8.4% w/w and Sulphur concentration (SO₃) of 24% w/w
3. Granulated ammonium sulphate: Its main characteristic is that it is slowly soluble and used in pre-seeding or in tree crops.
   When water cannot be incorporated through fertirrigation (period of rainfall or puddling).
   It contains the same richness as any other formula, and its contribution to crops such as almond, olive or fruit trees is quite common, especially at the time of budding and the development of new leaves.

 

BENEFITS FOR CROPS

• It is a cheap source of nutrients.
• It allows for more uniform solid mixtures with other granulated products.
• It is very versatile in its application, both in time (spring, summer, etc.) and in soil types.
• It supports rapid growth, crop yield and profitability.
• It is very environment-friendly, protecting aquifer environments and reducing nitrate washing losses.
• It increases the availability of phosphorus and increases the availability of micronutrients.
• It especially enhances soils with an alkaline pH or calcareous soils.

 

AMMONIUM SULPHATE AS A FERTILISER

• If the correct dose is applied, it provides an optimal nutritional source, which is very easy to mix and use.
• In hydroponic crops, its use is limited to a maximum of 15-20% of the total fraction of Nitrogen, the remaining being Nitric Nitrogen.
• Its process is obtained through synthesis transformations and, as such, is not covered by European organic farming regulations.
• The form of Ammonium is quickly assimilated by each crop, although in large volumes it can become phytotoxic to the plant.

 

APPLICATION METHODS

There are three types of application of ammonium sulphate:

• Surface: Distributed over the surface, broadcasted and in strips.
• Via irrigation water: Its high solubility allows it to be used for fertirrigation.
• Underground: Applied in strips alongside or under the seeds.

 

APPLICATIONS

WINTER CEREAL
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
Dry: Budding Irrigation: Half budding, start of sprouting	1500 – 2500	150 – 200	150 – 200
	2500 – 5000	200 – 350	200 – 350
	5000 – 7000	350 – 500	350 – 500

 

SPRING RICE CEREAL
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
Start of Budding	7000 – 8000	700 – 800	175 – 200
	8000 – 9000	800 – 900	200 – 250
	9000 – 11000	900 – 1000	250 – 300

 

SPRING MAIZE-SORGHUM CEREAL
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
Long cycle: Half at 30cm, rest per month Short cycle: Single application at 50cm	8000 – 10000	500 – 650	500 – 600
	10000 – 12000	650 – 775	600 – 750
	12000 – 14000	775 – 875	750 – 850

 

INDUSTRIAL SUNFLOWER CROP
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
Depending on humidity, followed by thinning	1500 – 2000	200 – 250	100 – 150
	2000 – 3000	250 – 350	150 – 250

 

INDUSTRIAL COTTON CROPS
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
50% after thinning 50% 30 days later	3000 – 4000	250 – 350	650 – 750
	4000 – 5000	350 – 450	750 – 850

 

MISCELLANEOUS INDUSTRIAL CROPS
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	TOP Kg/Ha
Applied twice throughout the cycle	30000 – 40000	350 – 450	350 – 450
	40000 – 50000	450 – 550	450 – 550
	50000 – 60000	550 – 650	550 – 650

 

OLIVE GROVE
APPLICATION	PRODUCTION Kg/Ha	AFTER COLLECTION Kg/Ha	TOP Kg/Ha
Spring if it rains, has rained, or is going to rain	20 – 30	3	1.5
	30 – 40	4	2
	40 – 50	5	2.5
	50+	6	3

 

VINES
APPLICATION	PRODUCTION Kg/Ha	DEEP Kg/Ha	WINTER DRESSING
One application in winter	8000 – 10000		500 – 700
	10000 – 12000		700 – 900

 

CITRUS LIMON VERNA-LATE VARIETIES
APPLICATION	PRODUCTION Kg/Ha waterlogged	DRESSING 1 Kg/Ha waterlogged	DRESSING 2 Kg/Ha waterlogged	DRESSING 3 Kg/Ha waterlogged
	3000 – 4000	60 – 70 January	30 – 40 July-August	30 – 40 October
	4000 – 5000	70 – 80	40 – 50	40 – 50

 

CITRUS CLEMENTINES – SATSUMAS – NAVEL – SALUSTIANAS
APPLICATION	PRODUCTION Kg/Ha waterlogged	DRESSING 1 Kg/Ha waterlogged	DRESSING 2 Kg/Ha waterlogged
Dressing 1: February/March Dressing 2: July/August	3000 – 4000	75 – 100	70 – 80
	4000 – 5000	100 – 125	80 – 100

 

 

ALMOND
APPLICATION	PRODUCTION Kg/Ha	A. WINTER Kg/Ha	WINTER DRESSING
Apply twice in feeding phase	5000 – 7000	400 – 500	200 – 250
	7000 – 9000	500 – 600	250 – 300
	9000 – 11000	600 – 700	300 – 350

 

APPLE – PEAR – QUINCE
APPLICATION	PRODUCTION Kg/Ha	A. WINTER Kg/Ha	WINTER DRESSING
Apply twice in feeding phase	20000 – 25000	450 – 500	500 – 600
	25000 – 30000	500 – 550	600 – 700

 

 

CHERRY – PLUM – PEACH – APRICOT – NECTARINE – SATURN PEACH
APPLICATION	PRODUCTION Kg/Ha	A. WINTER Kg/Ha	WINTER DRESSING
Apply twice in feeding phase	10000 – 15000	600 – 650	500 – 650
	15000 – 25000	650 – 700	650 – 800
	25000 – 30000	700 – 750	800 – 950

 

Remember that DFGRUPO remains at your disposal to recommend the products that best meet the needs of your crops and to answer any questions you may have. Please contact us, and we will be happy to discuss it with you!