This document provides an overview of fertilizers and the fertilizer industry. It discusses the types of plant nutrients and the role of major nutrients like nitrogen, phosphorus, and potassium. It describes the classification of fertilizers based on their chemical composition, nutrient content, physical state, and source. The document also covers the requirements of an effective fertilizer, straight and mixed fertilizers, fertilizer ratios, and the benefits of fertilizer use.

1. Chemical Process Technology
(Code: BCMPE501)
Professional Elective - I
5th Semester
Department of Chemical Engineering
Lecture 02

2. FERTILIZER INDUSTRY
INTRODUCTION
Fertilizers are the products that improve the levels of the available plant nutrients and/or the
chemical and physical properties of the soil, thereby directly or indirectly enhancing the
growth, yield and quality of the plant.
Fertilizers are compounds used to promote plants growth. They are usually applied either
through the soil, for uptake by plant roots, or uptake through leaves.
Fertilizers can be organic matter or inorganic chemicals or minerals. They can be naturally
occurring compounds such as peat or mineral deposits, or manufactured through natural
processes or chemical processes.
Fertilizers typically provide, the three major plant nutrients (phosphorous, nitrogen and
potassium), the secondary plant nutrients (sulphur, calcium and magnesium), and sometimes
trace elements (or micronutrients) with the role in plant nutrition: chlorine, boron, manganese,
zinc, iron, copper, and molybdenum.

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PLANT NUTRIENTS : Plants require following nutrient elements for their growth.
Natural nutrients :Carbon, hydrogen and oxygen are derived from air and water and so these are called
natural nutrients.
Primary nutrients : Nitrogen, phosphorus and potassium are consumed in large amounts by the plants for
their growth and so these are called primary nutrients.
Secondary nutrient :Calcium, magnesium and sulfur which occur to a limited extent in all soils, are called
secondary nutrients.
Micronutrients :Zinc, boron, copper, manganese, chlorine, iron and molybdenum are required in little
amount by the plants and so these are called micro nutrients.

4. FUNCTION OF NUTRIENT
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The role of various nutrients in the plant growth is as follows
Nitrogen :
Nitrogen supplied as nitrate ion or ammonium salt is one of the important constituent for synthesis of
amino acids which are then converted into proteins and enzymes. Proteins thus formed make part of the
protoplasm, while enzymes act as catalysts for various reactions taking place in the plants.
Nitrogen is also a special constituent of the chlorophyll, without which photosynthesis is not possible.
Nitrogen makes up 16-18% of the plant protein and constitutes 1-4% of the dry weight of plants and is
required in large amounts of any of the plant nutrients.
Sources of nitrogen :
1.Atmosphere
2.Organic nitrogen compounds formed in the soil by recurring natural processes
3.Fertilizers
The natural sources are not sufficient for adequate plant growth and so artificial nitrogen compounds in the
form of fertilizers are added to the soil.

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Phosphorus(P) :
It is required in much lesser amounts than nitrogen. Most soils contain phosphate in the form of
complex calcium phosphate, aluminum and iron complexes and organic compounds. Such
sources are insoluble and so the plants can make very little use of them.
Phosphates are involved in the respiratory and photosynthetic processes which provide energy
in some of the plants metabolic processes without which the plant could not live. The need of
phosphorus is also necessary for the health of the plant as it is constituent of nucleic acids,
phytins and phospholipids. It is also found in seeds and fruits.
The phosphorus has also been found to contribute to the formation of the reproductive parts in
the early life of the plant.
Potassium(K) :
It is necessary to the development of starches of potatoes and grains, the sugar of fruits and
vegetables and the fibrous material of plants.
An ample supply of potassium in the soil sometimes helps to prevent disease and to lessen the
effects of excessive nitrogen application.

6. NEED OF FERTILIZER
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It can be def i
ned as the quantity of additional nutrients required by a particular crop to
increase its growth to the optimal level in a given soil.
After repeated cultivation the soil reached to a stage where it becomes less productive, if
supply of the above nutrients is not provided.
Thus, in order to make up this def i
ciency, certain elements in the form of their compounds
have to the added to the soil to make it reproductive. These substances are known as
fertilizers.
Fertilizing the land is essential due to following reason
Provide nutrient essential for growth and better yield.
Maintain the pH of the soil in the vicinity of 7-8 to facilitate optimum growth
Provide food supplement to the plants

7. Classification
1. Based on their chemical composition :
Organic products: Produced out of wastes of animal husbandry (stable manure, slurry manure,
etc.), plant decomposition products (compost, peat, etc.), or products from waste treatment
(composted garbage, sewage sludge, etc.).
Mineral fertilizers: Contains inorganic or synthetically produced organic compounds.
Synthetic soil conditioners: It‘s main function is to improve the physical properties of the soil.
2. Based on their nutrient content
Micronutrient fertilizers: Containing nutrients required in small quantities by plants.
Straight fertilizers: Containing one primary nutrient, and/or one or more secondary nutrients.
Compound fertilizer: Also known as complex or multi-nutrient fertilizers. It contains several
primary nutrients and sometimes micronutrients.

8. Classification
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3. Based on the physical state
Solid fertilizer: Packed in bags
Liquid fertilizers: Packed in containers
4. Based on the source
Fertilizers can be obtained from natural and artificial sources
a) Natural organic fertilizers
Animal matter: Powdered dry fish and red dry blood from the slaughter house are important nitrogenous
fertilizers.
Farm yard manures: Typical farmyard manure consists of cow dung, sheep dung and human excretions.
Guano: Guano is a classic example of complete fertilizer and it is a mixture of bird 's excrement, fish
refuge and fish hones.
Plant matter: Oil cakes from cotton seed meal; linseed meal and caster cake belong to this class and
contain 7%, 5.5% and 6% of nitrogen respectively.

9. Classification
b) Natural inorganic fertilizers
Rock Phosphates: Finely divided rock phosphate, although insoluble in water, weathers rapidly and may be
used directly. Bone metal is another source which supplies phosphorus but phosphorus is exclusively supplied by
the artificial sources.
Chile Salt petre : Chilean deposits would not last for more than 250 years, even at present about 83% of the
world's requirements of NaNO3 come from artificial sources.
Potassium Salts: Natural potassium sources are wood ash (containing 5-6% potash) and waste materials
of sugar beet crops.
These natural organic and inorganic fertilizers are not sufficient to make the soil productive, as they can no
wholly meet the demand. Hence fertilizers are made artificially.
c) Artificial fertilizers
One of the major problems for modern fertilizer industry is to determine the most effective and economical
materials for supplying the nutrients. These may be developed under three groups, according to the nature
of the element.
Phosphorus fertilizer Nitrogenous fertilizer Potassium fertilizer

10. Nitrogen is usually supplied either in the nitrate or in the ammonical form. For most
agricultural situations it makes little difference which form is used, because the ammonical
form is converted rapidly to nitrates in the soil by the action of nitrifying bacteria.
In special cases, e.g., in case of low soil temperature, nitrif i
cation may be delayed: For
example, urea requires a little longer time to reach nitrate stage, because it must f i
rst
hydrolyze to the ammonical form.
Phosphates are supplied in calcium phosphate or ammonium phosphate forms to the plant.
Dicalcium phosphate is the principal phosphate constituent in nitric phosphate and
ammoniated super phosphate.
Potash as source of potassium is available in natural deposits in low cost. So selection of
potassium fertilizer is not a great problem compare to nitrogen and phosphorous fertilizers.
Sulfur is supplied as ammonium sulfate and potassium sulfate, and in the calcium sulfate
found in one form of superphosphate. Micronutrients are usually supplied as soluble sulfate.

11. Straight and mixed fertilizers
Straight fertilizers are sometimes used in special situations, like giving the plant an
additional supply of nitrogen after it is used up, thereby reducing leaching loss and
ensuring an adequate supply of nitrogen throughout the growth period.
Potash is often added to pastures as a straight material. Phosphate is also applied
straight, but too much lesser extent than in mixed fertilizers. The amount of nitrogen in
straight form is more than six times as that of phosphate or potash.
More than one nutrient is required for most of crops application. The farmer could
purchase single nutrient materials and apply them separately or mix them together
before application. Mixed fertilizers are prepared by mixing appropriate amounts of
ammonium salts, superphosphate and potassium salts.

12. REQUISITE AS FERTILIZER
The chief requisites of a fertilizer are
Must be soluble in water
The element present in the compound must be easily available to the plant
Should be cheap
Should not be toxic to plant
Should be stable for long time
Should maintain the pH of the soil in the vicinity of 7 to 8.
The most important factor of fertilizers is the movement of water in the soil. Application of
lime opens the pores of the soil and enables a free circulation of water.

13. Fertilizer ratio
Commercial fertilizer has specific ratio of nutrients, or fertilizer ratio or plant food ratio.
It is the ratio of the number of fertilizer units in a given mass of fertilizer expressed in the
order N, P and K. Thus, it is the ratio of two or more nutrient percentages to one another.
For instance, a fertilizer with 5-10-15 grade has 1-2-3 ratio, whereas a fertilizer with 10-20
-20 grade has 1-2-2 ratio. Fertilizer ratio is also defined as the relative proportion of primary
nutrients in a fertilizer grade divided by the highest common denominator for the grade. For
example, the grade 16-12-20 has a ratio of 4-3-5 of N, P and K, respectively.

14. Fertilizer benefits
The fertilizer benefits to the human environment are as follows
a) Farming efficiency improvement
The farmer's income can be increased by the application of fertilizers. If the use of economic optimum
levels of fertilizer is consistent, negative consequences are minimized.
b) Improvement of soil quality with adequate fertilization
The aggregating action from enhanced root proliferation and a greater amount of decaying residues have
reportedly made the soil more friable, tillable and water retentive.
c) Crop quality improvement
The mineral, protein and vitamin contents of crops can be improved by balanced fertilization.
d) Water conservation
Plants well nourished by fertilizers, use water efficiently through their expanded root system, thereby
reducing water evaporation losses and conserving this natural resource.