Skip to main content

Why Nitrogen Is Essential for Plant Growth

A botany graduate, Nithya Venkat enjoys writing about plants that help sustain life on planet Earth.


Nitrogen is a gas that is essential for plant growth. It is present in the surrounding atmosphere and is the most common gaseous element that accounts for 78 % of the earth’s atmosphere.

Even though Nitrogen is present in the atmosphere in abundance, plants cannot use nitrogen in its gaseous form. Plants can absorb Nitrogen from the soil only in the form of ammonium, nitrites, and nitrates.

About Nitrogen

Nitrogen is a gas with a chemical symbol N. It is nonmetallic, colorless, odorless, tasteless, and has an atomic number of 7 with an atomic weight of 14.0067. Nitrogen is slightly lighter than air and has a density of 1.251 grams/liter at 0 degrees Centigrade and a specific gravity of 0.96737.

Role of Nitrogen In Plant Growth

Nitrogen is an important component in plant cells that help perform metabolic functions essential for the growth and reproduction of plants. Presenting below how nitrogen helps plants to grow, flourish and reproduce.

Structure of a Chlorophyll (N represents Nitrogen)

Structure of a Chlorophyll (N represents Nitrogen)

Production of Chlorophyll

Chlorophyll is a green color pigment that helps in the process of photosynthesis. Photosynthesis is a process through which plants get the energy that they need to grow and reproduce.

During photosynthesis, chlorophyll in the leaves absorbs light energy from the sun and uses it to split water molecules into hydrogen and oxygen. The oxygen is released into the atmosphere, and hydrogen and carbon dioxide are used to form glucose that gives energy to the plants. Some of this glucose is stored in the plant to be used as and when needed.

Nitrogen is part of the chlorophyll molecule that gives the green color to the plants. In the absence of nitrogen, the chlorophyll content is depleted, and photosynthesis is considerably reduced. This results in stunted growth, yellowing of leaves, and wilting of plants.

Structure of Amino Acid (N represents Nitrogen)

Structure of Amino Acid (N represents Nitrogen)

Production of Amino Acids & Proteins

Nitrogen is a major component of amino acids that form the building blocks of protein.

Amino acids are organic compounds that are made of carbon, hydrogen, oxygen, nitrogen. These amino acids combine in different ways to form proteins.

There are twenty amino acids that plants combine to form proteins, and all these twenty proteins have to be produced by the plants. Without nitrogen, the plant cannot produce amino acids.

Lack of nitrogen will lead to reduced production of amino acids by the plant cells, which will lead to a lack of protein needed for the metabolic functions of plant cells.

Some proteins in plants act as structural units in cell walls, and cell membranes and other proteins act as enzymes that enable biochemical reactions essential for plant growth and reproduction.

Structure of DNA

Structure of DNA

Production of Genetic Material

The genetic material DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) present in plant cells are made of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorous. Without Nitrogen, the genetic material cannot exist.

The DNA contains the traits of a specific plant, and when the plant cells reproduce, this information is copied and passed onto the new cells—the RNA consist of the instructions passed on by the DNA for the manufacture of proteins.

Scroll to Continue


DNA is made of two linear strands twisted in the shape of a double helix. These strands are made of a phosphate-deoxyribose sugar backbone connected across by rungs of the nitrogenous bases such as adenine (A), Guanine (G), Cytosine (C), and Thymine (T). In the double-stranded helix, Adenine pairs with Thymine and Guanine with Cytosine.

The RNA is made of Ribonucleic acid, and it has the coding information passed on by the DNA for the manufacture of proteins. It is single-stranded and is made of phosphate-ribose sugars and the nitrogenous bases Adenine, Thymine, Guanine, and Uracil.

Nitrogen is vital for the formation of nitrogenous bases. Without the nitrogenous bases, the DNA and RNA molecules would be incomplete and not perform the functions vital to plants' existence.


How do plants obtain nitrogen from the air?

Nitrogen is the most abundant element in the air, but it is not present in a form that plants can use. The molecular nitrogen present in the air has two Nitrogen atoms that are triple bonded to each other. This bond is strong and difficult for the plants to break to obtain a form of Nitrogen that they can use.

The process of breaking down two Nitrogen molecules is called Nitrogen Fixation.

In a symbiotic relationship, the Rhizobium bacteria present in the roots of Leguminous plants fix the nitrogen in the atmosphere and convert it into ammonia, a form that plants can absorb and use for growth and reproduction. The leguminous plants, in turn, supply carbon to the Rhizobium bacteria.

A small amount of Nitrogen in the atmosphere is fixed during lightning and solar radiation.

Plants also obtain the Nitrogen that they need through Nitrogen fertilizers that are added to enrich the soil.

Nitrogen Fertilizers

Lack of Nitrogen in the soil can lead to a low yield of weak crops. Nitrogen fertilizers are added to the soil to enable healthy plant growth and ensure a better crop yield.

Farmers test the soil to determine the nitrogen content of the soil. Depending upon the crops grown and the yield to be achieved, the amount of nitrogen fertilizer added to the soil is calculated.

If plants are supplied with an excess of nitrogen, they begin to produce protoplasm at a rapid rate, but at the same time, they are not able to produce the cellular structures needed to enclose the protoplasm in cells. This results in weak plants that can be damaged easily, thereby leading to a low yield.

Nitrogen fertilizers are used to make up for the lack of Nitrogen in the soil. Nitrogen fertilizers must be used to not leach out from the soil and pollute the environment.

To Summarize

Nitrogen is a gas that enables plants to perform metabolic functions essential for their growth and reproduction. Nitrogen is the most abundant element in the air, but it is not present in a form that plants can use.

Plants obtain the nitrogen that they need through a process called Nitrogen Fixation. A small amount of nitrogen is fixed during lightning. Leguminous plants get the Nitrogen that they need through a symbiotic relationship with the Rhizobium bacteria. Plants also obtain nitrogen through the fertilizers that are added to the soil.

Nitrogen is a part of chlorophyll, amino acids, proteins, and genetic material in plants essential for the growth and survival of plants.

Without access to the optimum level of nitrogen, plants will not grow, flourish, and reproduce.



Mosaic-Crop Nutrition

Journal of Experimental Botany

© 2017 Nithya Venkat


Nithya Venkat (author) from Dubai on February 18, 2019:

Audrey thank you for your appreciation.

Audrey Hunt from Pahrump NV on February 14, 2019:

Thank you for this informative hub about Nitrogen. I've learned a great deal by reading your well-written article. I had no idea how important nitrogen is to the growth of plants.

Nithya Venkat (author) from Dubai on June 01, 2018:

Shalloo thank you.

Shaloo Walia from India on June 01, 2018:


Nithya Venkat (author) from Dubai on May 31, 2018:

Nell Rose thank you.

Nell Rose from England on May 29, 2018:

Really interesting and something I knew little about, great hub!

Nithya Venkat (author) from Dubai on May 07, 2018:

Thank you Frank Atanacio.

Frank Atanacio from Shelton on May 06, 2018:

A very informative and educational piece Vellur... thak you for sharing...

Nithya Venkat (author) from Dubai on April 27, 2018:

manatita44 thank you, I enjoy reading Linda Crompton’s articles.

manatita44 from london on April 24, 2018:

Very good article on nitrogen and its usefulness with so many things. You remind me of Linda Crompton. Different as you should be, but complimentary. Excellent Article!

Nithya Venkat (author) from Dubai on April 08, 2018:

Peggy yes the chemical fertilizers do differ depending on the season. Thank you for stopping by.

Peggy Woods from Houston, Texas on April 01, 2018:

This was interesting to read regarding nitrogen and its use in successfully growing plants. The ratios of nutrients are always different in spring fertilizers verses those put down in fall if using chemical fertilizers.

Nithya Venkat (author) from Dubai on January 15, 2018:

Hari Prasad S thank you.

Nithya Venkat (author) from Dubai on January 15, 2018:

Jackie Lynnley thank you.

Hari Prasad S from Bangalore on December 21, 2017:

Very informative and useful hub nithya.

- hari

Jackie Lynnley from the beautiful south on December 19, 2017:

Keep up the good work and Merry Christmas!

Nithya Venkat (author) from Dubai on October 28, 2017:

Jackie Lynnley thank you and am glad you enjoyed reading.

Nithya Venkat (author) from Dubai on October 28, 2017:

Linda thank you, Nitrogen as such has many different properties. It is interesting to read about Nitrogen.

Nithya Venkat (author) from Dubai on October 28, 2017:

Eric Dierker am glad that this article helped you decide the type of fertilizer to use.

Jackie Lynnley from the beautiful south on October 27, 2017:

Wow, something lighter than air. I can't imagine it, other than a ghost! You write so well to understand. I enjoyed this educational article so much. Thank you!

Linda Crampton from British Columbia, Canada on October 27, 2017:

Thank you for sharing so many details about nitrogen in this very informative article, Nithya.

Eric Dierker from Spring Valley, CA. U.S.A. on October 27, 2017:

Perfect timing. I need to do some fertilizing right now. You have helped me decide which to use with nitrogen and less yukky stuff. Thanks much.

Nithya Venkat (author) from Dubai on October 27, 2017:

Bill thank you, you are a great farmer and your farm is amazing.

Nithya Venkat (author) from Dubai on October 27, 2017:

Chitrangada Sharan thank you and am happy that you found this article informative.

Nithya Venkat (author) from Dubai on October 27, 2017:

Devika thank you for taking the time to read and leave a comment, much appreciated.

Nithya Venkat (author) from Dubai on October 27, 2017:

Ann Carr thank you, you are so kind and generous with your appreciation. I am so happy that you enjoyed reading this article.

Nithya Venkat (author) from Dubai on October 27, 2017:

FlourishAnyway thank you and am glad you found it interesting. The love of nature drew me towards the study of plants.

Bill Holland from Olympia, WA on October 27, 2017:

As a gardener and urban farmer, I always love articles like this one, to help me to better understand the process of growing. Thank you for some great information.

Chitrangada Sharan from New Delhi, India on October 27, 2017:

Great educational hub, very well written and presented!

I learnt a lot about how plants absorb nitrogen and how it helps in their growth.

Thanks for sharing this information!

Devika Primić from Dubrovnik, Croatia on October 27, 2017:

Informative and useful. I read from your knowledge and glad to have learned this much about a topic seldom talked about in our world.

Ann Carr from SW England on October 27, 2017:

Thanks for this detailed information. I enjoy gardening and this gives me some important background as I'm no scientist! You've explained it without 'blinding me with science' and you are obviously very knowledgeable - the diagrams are great.


FlourishAnyway from USA on October 27, 2017:

Glad to see you added a profil picture! This was interesting. I do not have a green thumb at all. I’m so impressed you have a degree in botany. I’d love to know what inspired your love of plants and what you plan to do with your degree.

Related Articles