Differences between mixed
fertilisers and complex
fertilisers
Inorganic, complex, mixed, liquid and pure fertilisers, and the composition of them
Henning Lyngsø FOGED (MSc Agriculture), enAgro, Denmark
2
Purpose of the presentation
 Terminology of fertilisers according EU’s Fertiliser Regulation
 Production of inorganic fertilisers
 Definition of inorganic fertilisers and sub-types
 Presentation of inorganic fertilisers and examples of their chemical
composition
 Differences between complex and mixed fertilisers
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
26-10-2015
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Those with
a green
border are
defined in
EU’s
Fertiliser
Regulation,
while the
others
generally
are
popular
terms
Terminology
Chelated fertiliser
Inorganic fertiliser
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
27-10-2015
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Inorganic fertiliser types
 Many soils require the addition of several essential nutrients to alleviate
plant deficiencies.
 Farmers may have the option of selecting a combination of single-nutrient
fertilisers or using a fertiliser that has several nutrients combined into each
particle.
 These combination (compound or complex) fertilizers can offer advantages
of convenience in the field, economic savings, and ease in meeting crop
nutritional needs.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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More or
less
synonyms
Terminology - grouped
Fertilisers on liquid form
and the way the
nutrients are blended
Inorganic fertiliser
Compound fertiliser
Fluid fertiliser
Mineral fertiliser
Straight fertiliser
Suspension fertiliser
Artificial fertiliser
Complex fertiliser
Solution fertiliser
Chemical fertiliser
Blended fertiliser
Liquid fertiliser
Mixed fertiliser*
Terms that relates to
the number of plant
nutrients the fertiliser
contains and how it is
produced. Unless
otherwise stated, on
solid form.
Pure fertiliser
Complete fertiliser
Terms that are used to
explain the way the
fertiliser works
Foliar fertiliser*
Slow release fertiliser
Start fertiliser
* Can also be organic
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Inorganic fertilisers raw material
 Inorganic fertiliser raw materials are also called primary fertilisers:
Production
price
depends
on energy
prices
 Nitrogen are via the Haber-Bosch process extracted from the atmosphere and fixated
in the form of ammonia. Ammonia can further react with nitric acid and become
ammonia nitrate.
 Phosphorus comes from phosphate rock, it is treated with sulfuric acid, producing
phosphoric acid. Some of this material is reacted further with sulfuric acid and nitric
acid to produce a triple superphosphate, an excellent source of phosphorous in solid
form. Some of the phosphoric acid is also reacted with ammonia in a separate tank.
This reaction results in ammonium phosphate, another good primary fertilizer.
 Potassium chloride is extracted from minerals sylvite, carnallite, and potash. It is also
extracted from salt water and can be manufactured by crystallization from solution,
flotation or electrostatic separation from suitable minerals. It is a by-product of the
production of nitric acid from potassium nitrate and hydrochloric acid. The
manufacturer converts it into a more usable form by granulating it. This makes it easier
to mix with other fertilizer components in the next step.
 Micro nutrients are typically mined.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
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Inorganic fertilisers raw material
 Inorganic fertiliser production explained in simplicity
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing Fertilisers, Cairo 26-27/102015
27-10-2015
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Chemical composition of primary
fertilisers
Type
Formula
Ammonia*
Ammonium nitrate*
NH3
82
(NH4)(NO3)
35
Triple superphosphate*
Ca(H2PO4)2•H2O
Ammonium phosphate
(NH₄)₃PO₄
Potassium chloride*
N, %
KCl
P 2 O5 , %
K2O, %
45
28
21
52
* Pure = straight = simple = single nutrient fertilisers
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing Fertilisers, Cairo 26-27/10-2015
27-10-2015
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Examples of other pure fertilisers
N, %
Urea
46
Ammonia sulphate
21
Prilled ammonium nitrate
34
Ammonium nitrate / calcium carbonate
Superphosphate
Potassium sulphate
P 2 O5 , %
K2O, %
21-26
18-21
52
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Fertilisers, Cairo 26-27/10-2015
27-10-2015
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Comments on primary and pure
fertilisers
 Representative sampling is easy – it is uniform products
 The price of the nutrients are relatively low due to the low level of
processing
 They are costly to use, because the application of NPK to a field must be
done in at least three operations, and each operation takes time, costs
money (diesel, machinery depreciation and maintenance), and driving on
the field with machinery leads to compaction of the soil.
 The dosing can happen exactly so they comply with the norms
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
27-10-2015
Fertilising example with pure fertilisers
compared to complex fertilisers
11
1 ha wheat
Kg
Norm, kg per ha
184
Ammonium nitrate
527
Triple superphosphate
Potassium chloride
Balance
N
P 2 O5
K2 O
37
124
184
81
1 ha wheat
Norm, kg per ha
NPK 18-9-13
Kg
N
P 2 O5
K2 O
184
37
124
1022 184
92
133
0
+55
+9
37
239
124
0
0
0
Balance
What is
best???
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
27-10-2015
Mixed and
complex /
compound
12 are
fertilisers
artificial
fertilisers, which
is the same as
mineral
fertilisers. They
are often
complete
fertilisers,
containing all
three main
plant nutrients,
N, P and K.
They are
typically solid
fertilisers on a
granular form,
spread with a
disc spreader
like shown
here.
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Mixed fertilisers
 A mixture of two more straight fertiliser materials is referred to as fertiliser
mixture. Sometimes, complex utilises containing two plant nutrients are also
used in formulating fertiliser mixtures. Complete fertiliser refers to the
fertilisers containing three major plant nutrients, N, P2O5 and K2O.
 Mixed fertilisers are also called "Blended fertiliser“, meaning a fertiliser
obtained by dry mixing of several fertilisers, with no chemical reaction.
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Mixed fertilisers
 If the mixed fertilisers are
of different granule size
or density, the risk is that
the nutrients by
spreading are unevenly
distributed on the field,
because the largest and
heaviest granules tends
to fly longest, while dust
and small granules
dumps down shortly
behind the spreader and
is taken by the wind.
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Fertilisers, Cairo 26-27/10-2015
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The largest
granules are
flying longest
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Fertilisers, Cairo 26-27/10-2015
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Mixing fertilisers
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Mixed or complex – the difference is
visible
Mixed fertiliser
Complex fertiliser
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Changes that occur while manufacturing
mixed fertiliser
 The ingredients used in fertiliser mixtures vary widely in their physical and
chemical characteristics.
 When such widely varying materials in physical and chemical properties
are mixed together, naturally many changes are expected to take place
during or after the mixing.
 Some changes will be of physical nature and some will be of chemical
nature.
 The following are the most important physical changes that will take place
during or after the mixing of fertilisers.
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Changes that occur while manufacturing
mixed fertiliser
 Hygroscopicity
 It is a property of any substance which absorbs from air and gets converted to semi-solid or
liquid condition. Fertilisers like Ca(NO3)2, NH4NO3 and NaNO3 are capable of absorbing
moisture from air and become hygroscopic. In such cases handling will be very difficult for
such mixtures.
 Caking up
 Moisture present in some of the ingredients is responsible for caking up.
 Moisture dissolves some of the easily soluble ingredients and forms a saturated solution. This
saturated solution on evaporation gives out crystals which knit together forming larger lumps.
 The caking up can be prevented by the use of certain kind of materials called as
‘conditioners’. The commonly used conditioners are groundnut hulls, lime, clay etc. Another
was of preventing the caking up is manufacture of granulated fertiliser mixture.
 The granulation aims at preparation of uniform sized particles with reasonable stability, which
presents caking up.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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Changes that occur while manufacturing
mixed fertiliser

Segregation
 This relates to separation of different sized particles individually.
 When ingredients of different sizes and densities are included there will be the tendency for the segregation
(sorting out to different sizes) to take place.

The following are some of the most important chemical changes that take place either during or
after the manufacture of fertilizers mixtures. These changes are found to be influenced by
temperature, moisture content and particle size of the in gradients:
a.
Double decomposition: The reaction is between two compounds without a common ion in the presence
of moisture. New compounds are formed which may have different physical and chemical properties.
b.
Neutralization: This reaction takes place when free acids present in some of the fertilisers are neutralised by
alkalis or Ca containing salts included in the mixture
c.
Hydration: The process of tying up of water by the anhydrous form of salts is called hydration. Some of the
fertilisers are found to have this property.
d.
Decomposition: Under certain conditions of moisture and temperature, there will be break down in the
composition of molecules forming new compounds.
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Changes that occur while manufacturing
mixed fertiliser
 The following important principles must be taken into consideration while
preparing mixed fertilisers.
1. All fertilizers containing ammonia are not mixed directly with the alkali fertilisers
(e.g. rock phosphate and limestone) as reaction will take place resulting in the
loss of gaseous NH3.
2. The water – soluble phosphates are not mixed with those materials which
contain free lime (e.g.) lime stone, CaCN2) as there will be reaction towards the
reversing of water – soluble phosphate to water – insoluble phosphates.
3. Hygroscopic fertilisers are not included as they will facilitate caking up.
4. The acidic fertilisers are likely to produce some free acids which may damage
the container or packing materials.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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With other words: mixing fertilisers is not
for amateurs
 However, if blended / mixed fertilisers
are marketed, they shall according the
EU Fertilisers Regulation be marked as
such, and they must be blended in a
way so that no chemical reaction takes
place after the blending.
 Ammonia nitrate is explosive!
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Mixed fertilisers - advantages
 Mixed fertilisers allow to design the fertiliser exactly to the need of each
crop/field, so that
 Each nutrient is in balance with the norm (but it does seldom happen in practice)
 One field application is enough – saves time and money
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Complex fertilisers
 Complex fertilizers - are fertilizers during the production of which a chemical
reaction occurs among the components which react reciprocally, whereby a
homogenous product of uniform composition is created, representing certain
chemical compounds.
 They may also be produced with elements that provide some of the lesscommon plant nutrients (known as secondary or trace nutrients, such as sulphur,
calcium and magnesium).
 Compound fertiliser can be packaged and distributed in liquid or granular form.
 A numbering system is used to define the percentages of the three essential
plant nutrients. For example, a 20-20-10 fertilizer would contain 20 percent
nitrogen, 20 percent phosphorus and 10 percent potassium. Secondary nutrients
and trace elements are typically listed.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
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Complex fertilisers
 Example of complex
fertilisers in a granular form
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Fertilisers, Cairo 26-27/10-2015
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Complex fertilisers
 Complex fertilisers are made using basic fertiliser materials, such
as NH3, ammonium phosphate, urea, S, and K salts. There are
many methods used for making these fertilisers, with the specific
manufacturing processes determined by the available basic
components and the desired nutrient content of the finished
product. Here are three brief examples.
 Compaction methods (agglomeration) involve binding small fertiliser
particles together using compaction, a cementing agent, or a
chemical bond. Various nutrient ratios can be combined using
undersized particles that may not be suitable for other applications.
 Accretion-based fertilisers are made by repeatedly adding a thin film
of nutrient slurry which is continually dried, building up multiple layers
until the desired granule size is reached.
 Pipe-cross reactors are used to chemically melt NH3, acids containing
S or P, and other nutrients—such as K sources and micronutrients—
into a solid fertiliser with the desired nutrient content.
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Complex fertilisers
 Complex fertilisers contains multiple nutrients in each individual granule.
 This differs from a blend of fertilisers mixed together to achieve a desired
average nutrient composition.
 This difference allows complex fertilizer to be spread so that each granule
delivers a mixture of nutrients as it dissolves in the soil and eliminates the
potential for segregation of nutrient sources during transport or application.
 A uniform distribution of micronutrients throughout the root-zone can be
achieved when included in complex fertilisers.
 These fertilisers are especially effective for applying an initial nutrient dose in
advance of planting. There are certain ratios of nutrients available from a
fertiliser dealer for specific soil and crop conditions. This approach offers
advantages of simplicity in making complex fertiliser decisions, but does not
allow the flexibility to blend fertilisers to meet specific crop requirements. Turf
managers and homeowners often find complex fertilisers desirable.
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Complete
fertilisers
Complex
fertilisers
with two
nutrients /
binary
Examples of complex fertilisers
N, %
P 2 O5 , %
K2O, %
NPK 16-16-16
16
16
16
NPK 6-26-30
6
26
30
DAP NP 18-46
18
46
NP 26-13
26
13
Basfoliar
20
19
FoliQ MikroMax
0.64
19
1.29
Mg, %
0.5
S, % Ca, %
Na, %
Mn
B Zn Fe
Cu
Mo
0.8
 




0.64
 




Liquid, foliar
fertilisers
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Liquid fertilisers
 90% of all fertilisers used globally are solid, and 10% liquid;
 Liquid fertilisers are said to have a quick effect, and it is logically given to
growing crops, often in the stage of peak growth.
 Liquid fertilizers comprise anhydrous ammonia, aqueous solutions of ammonia,
aqueous solutions of ammonium nitrate or urea
 Liquid fertilisers can roughly be divided into
 Conventional complex fertilisers of solution or suspension type – these fertilisers are
spread on the crops via irrigation systems, and the operation called fertigation;
 Foliar fertilisers are applied directly to leaves. The method is almost invariably used to
apply water-soluble straight nitrogen fertilisers and used especially for high value crops
such as fruits. Some foliar fertilisers contain chelated micronutrients;
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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Liquid fertilisers
 UAN is an abbreviation for urea and
ammonium nitrate.
 It is a solution of urea and
ammonium nitrate in water.
 The table shows different grades of
the UAN fertiliser.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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Foliar fertilisers
 Foliar fertilisers may be spread
with a field sprayer, and in some
cases even sprayed out in a
mixture with pesticides, provided
the mix is compatible.
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Ways of storing liquid fertilisers
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Liquid fertilisers
 From a dealers
homepage.
 As seen, also sold in
small canisters for
garden owners.
 Examples of the
formulation is seen
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
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Liquid fertilisers
 Liquid fertilisers are generally easy to sample in a representative way.
 However, segregation can have taken place in case the nutrients are
included in a suspension.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
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Liquid fertilisers
 Example of a fertiliser that can be
described as
 based on waste, in this case fish
waste;
 Organic;
 Liquid;
 Not all nutrient N is soluble,
meaning part of it is suspended,
and this is also why it is
recommended to stir well before
using - the same shall be done
before sampling;
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
26-10-2015
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Summing up on differences on complex,
mixed and other inorganic fertilisers
This presentation has provided information about


Terminology of fertilisers, and a presentation of the way inorganic fertilisers are produced;

There are for fertilisers used many terms with more or less identical meaning. EU’s fertiliser regulation provides a legal definition of
the terms in EU.

All inorganic fertilisers are made of the same primary fertilisers; N and K production is based on energy consumption, while P and
most micronutrients are mined.

Primary and pure fertilisers can be applied completely in accordance with the norms, but are typically to costly to spread,
wherefore farmers have an interest to use fertilisers with a combination of nutrients, here under binary and complete fertilisers.
Mixed fertilisers;


Complex fertilisers;


Mixed fertilisers are relatively cheap but has many disadvantages, such as a requirement to avoid unwanted chemical reactions
and segregation, being a challenge also for representative sampling.
Complex fertilisers are easy to use (and to sample), but they are more expensive and it is in fertilisation almost impossible to avoid
imbalances of nutrients.
Liquid fertilisers;

Liquid fertilisers, here under foliar fertilisers are not used much, and the use is typically for high value productions, such as flowers
and fruit plantations.
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
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Contact
Henning L. Foged
[email protected]
Mobile +45 6141 5441
TAIEX Workshop INT MARKT 60089 on Methods of Sampling and Analysing
Fertilisers, Cairo 26-27/10-2015
27-10-2015