This document classifies and describes various types of fertilizers. It discusses the classification of fertilizers based on their nutrient components (nitrogenous, phosphorus, potash, etc.) and their action in soil (direct, stimulant, mixed). Important individual fertilizers are described in detail, including ammonium sulfate, urea, superphosphates, and potassium nitrate. Their manufacturing processes and uses are explained. The document concludes with some ill effects of excessive fertilizer use such as nutrient imbalance, toxicity, and environmental pollution.

1. CLASSIFICATION AND ROLE OF
FERTILIZERS
INDUSTRIAL CHEMISTRY

2. CONTENTS:
Introduction
Classification
Important fertilizers
 Ammonium sulphate
 Urea
 Superphosphates
 Potassium nitrate
Ill effects of fertilizers

3. INTRODUCTION
 DEFINITION: A fertilizer is a substance used to supply essential elements like
nitrogen, phosphorus and potassium to the soil. The soil must have the sufficient
amount of these elements to producehigh yield of crop.
 The essential qualities of a good fertilizer are as follows:
i. The nutrient elements presentin the fertilizer should be readily available to the
plants.
ii. Itshould not damage the plants.
iii. Itshould be fairly soluble in the water so as to enable it to dissolvein the soil.
iv. Itshould be stable.
v. Itshould be able to adjustthe acidity of the soil.
vi. Fertilizers must to be converted in to a form which the plant can assimilate
easily.
vii. Itshould be cheap.
viii. Itshould not produce extra heat that can damage the plant.
CLASSIFICATION
Itcan be done in two ways:

4. 1. On the basis of the nature of the elements present,
2. And by its action on the soil i.e., it may be the direct sourceof the plant food
or it may facilitate the utilization of the nutrient already present in the soil
by the plants.
This classification based on the nature of the elements present in fertilizers
is as follows:
FERTILIZERS
a) Nitrogenous Fertilizers: These types of fertilizers generally supply
nitrogen to the soil.
Examples: Ammonium sulphate {(NH4)2SO4}, Calcium ammonium nitrate
(CAN), basic Calcium ammonium nitrate {Ca(NO3)2CaO}, Calcium cyanamide
{CaNCN}, Urea etc.
b) Phosphorus Fertilizers: These fertilizers providephosphorus to the soil.
Examples: Super phosphateof lime, triple super phosphate, phosphateslag,
Ammoniated phosphates, Nitro phosphates etc.
Nitrogenous
Fertilizers
Phosphorus
Fertilizers
Potash
Fertilizers
NP
Fertilizers
NPK or
Complete
Fertilizers

5. c) Potash Fertilizers: These fertilizers providepotassiumto the plants.
Examples: Potassiumchloride, Potassium sulphate, Potassiumnitrate etc.
d) NP Fertilizers: These fertilizers contain two elements i.e., nitrogen and
phosphorus. Theseareformed by mixing together both the fertilizers.
Examples: Dihydrogen ammoniated phosphateNH4
H2
PO4
and calcium super
phosphateCa(H2PO4)2 2Ca(NO3)2.
e) NPK or Complete Fertilizers: These types of fertilizers provide all the
three essential elements viz nitrogen, phosphorusand potassiumto the soil.
It is obtained by mixing all the three types of fertilizers in suitable
proportions.
Fertilizers can also be classifiedbased on the action of these fertilizerson theplant.
This classification is as follows:
FERTILIZERS
i. Direct Fertilizers: These include ammonium and potassium salts,
nitrates, superphosphates etc., which aredirectly utilized by the plants.
ii. Stimulant Fertilizers: These types of fertilizers improve the condition
of the soil. When they areadded to the soil, it neutralizes and makes it loose.
Examples: humus, lime, gypsumetc.
iii. Mixed Fertilizers: It contain two or three primary elements. When the
fertilizering materials mixed, it is known as mixed fertilizers. For example:
Direct
fertilizers
Stimulant
Fertilizers
Mixed
Fertilizers

6. expression like4-8-2 is used for a mixed fertilizer containing 4% nitrogen, 8%
phosphorus and 2% potash.
IMPORTANT FERTILIZERS
i. Ammonium sulphateor sindrifertilizer
ii. Urea (carbamideNH2CONH2)
iii. Double and triple superphosphates
iv. Potassiumnitrate or Nitre or Indian Saltpetre (KNO2)
 Ammonium sulphate or Sindri fertilizer:
 Itis manufacturedatSindrifertilizer factory,Bihar.Hence, it is called as Sindri
fertilizer.
 Manufacturing process: Air and steam are passed over red hot coke. Then a
mixture of CO, N2 and H2 gas is formed.
𝑪 + 𝒂𝒊𝒓 → 𝑪𝑶 + 𝑵 𝟐
𝑪 + 𝑯 𝟐 𝟎 → 𝑪𝑶 + 𝑯 𝟐
 These gases are then passed over hot Fe3O4 and Cr2O3 and N2 and H2 are
mixed in the ratio of 1:3 and then converted into ammonia by Haber’s
process.
 Ammonia is now passedinto a suspensionofgypsumin water and CO2 is also
passed and obtained by the heating of CaCO3.

7. 𝑪𝒂𝑪𝑶 𝟑 → 𝑪𝒂𝑶 + 𝑪𝑶 𝟐
2NH3 + H2O + CO2 + CaSO4 → (NH4)2SO4 + CaCO3 + ppt
Ammonia Soluble
 The precipitate of CaCO3 is filtered off and filtrate containing (NH4)2SO4 is
concentrated and cooled in the vacuum.Thesecrystalsarepacked in thejute
bags for sale.
 Calcium carbonateobtained as by productand can be used as a raw material
in cement industry.
 This fertilizer contains 24-25% ammonia which is converted to nitrates in the
soil by nitrifying bacteria. These nitrates are easily taken up by the plants.
 Itis mainly used for rice, potato crops and basic soils. In acidic soil, it should
be used in combination with ground lime stone or chalk to neutralize the
acidity of the soil.
 It should not be used along with the seeds as it harmfulfor the germinating
seeds.
 Urea (carbamide, NH2CONH2):
Itis an excellent nitrogenousfertilizer and is manufactured byreacting
ammonia and carbon dioxide.
𝑪𝑶 𝟐 + 𝟐𝑵𝑯 𝟑 → 𝑵𝑯 𝟐 𝑪𝑶𝑶𝑵𝑯 𝟒
Ammonium carbamate
𝑵𝑯 𝟐 𝑪𝑶𝑶𝑵𝑯 𝟒 → 𝑵𝑯 𝟐 𝑪𝑶𝑵𝑯 𝟐 + 𝑯 𝟐 𝑶
Urea
 Urea separates as a dry powder and contains 47% of nitrogen. It has the
higher nitrogen content than other fertilizers.

8.  Its costof production is less and it can be used in all types of crops and soils.
 Urea has the disadvantage of being hygroscopic and hence requires better
quality package.
 If urea contains more than 2% of impurities, it cannot be used as a fertilizer
because it is not very stable.
 Urea should be applied at the sowing time but it should not come in contact
with the seeds.
 Itcan be used in combination with the dry soils.
 Double and triple superphosphates:
Now-a-days, double and triple superphosphates are prepared by
treating rock phosphate with phosphoric acid in a mixer. The reaction
productis allowed to flow on conveyor belt when it sets into a solid mass of
triple superphosphate.
Ca3(PO4)2 + 4H3PO4 → 3CaH4(PO4)2
Calcium phosphate Superphosphate
 It is a mixture of calcium dihydrogen phosphate Ca(H2PO4) and dihydrate
calcium sulphate (gypsum) CaSO4.2H2O.
 This fertilizer is water soluble and is readily assimilated by the plants.
 Ithas somedisadvantages also. Itis relatively dilutefertilizer, hencerequires
relatively heavy freight and handling charges and a large number of
expensive bags.
 Ithas setting tendency and is converted into heavy lumps.
 The acidity of this fertilizer causes the packageto rot.

9.  Potassium nitrate or Nitre or Indian Saltpetre (KNO2):
Crude Nitre occurs as efflorescence on the surface of the earth in
tropical countries. It is obtained from a mixture of solid salt petre (NaNO2)
and potassiumchloride(KCl).
𝐍𝐚𝐍𝐎 𝟐 + 𝐊𝐂𝐥 ⇌ 𝐊𝐍𝐎 𝟐 + 𝐍𝐚𝐂𝐥
The above equimolecular solution of NaNO2 and KCl is allowed to
evaporate by boiling and more amount of Sodium chloride gets separated.
When enough of Sodiumchloride has been separated, the solution is cooled
to crystallizeout potassiumnitrate.
It dissolves in soil, water, well etc. and is taken by the plants in the
formof solution through their roots.
These show good resultin sandy and chalky soil. Itis specially used for
meadow grass, tobacco, cotton, clove, coffee, corn and potatoes.
ILL EFFECTS OF FERTILIZERS
a) Micronutrient loss and imbalance
b) Nutrient toxicity
c) Deteriorates soilquality
d) Impairs water quality
e) Causes environmental pollution
f) Effect of fertilizers on crop yield and quality
g) Eutrophication

10. REFERENCE:
Fundamentals of Applied Chemistry: Dr. J. Ghosh
S. Chand and company ltd.
New Delhi

11. THANK YOU