The Effects of Nitrogen Fertilizer on Plant Growth

International Journal of Trend in Scientific Research and Development (IJTSRD)
Volume 7 Issue 5, September-October 2023 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470
@ IJTSRD | Unique Paper ID – IJTSRD60048 | Volume – 7 | Issue – 5 | Sep-Oct 2023 Page 1024
The Effects of Nitrogen Fertilizer on Plant Growth
Dr. Pallavi Dixit
Associate Professor, Department of Botany, Mahila Vidyalaya Degree College, Lucknow, Uttar Pradesh, India
ABSTRACT
Nitrogen is an essential element for plant growth and development;
however, due to environmental pollution, high nitrate concentrations
accumulate in the edible parts of these leafy vegetables, particularly
if excessive nitrogen fertilizer has been applied. The consumption of
these foods can be harmful to human health, thus it's critical to design
an effective plan for applying nitrogen fertilizer to crops. This study
used organic, inorganic, and liquid fertilizers to look at how they
affected nitrate levels and lettuce growth. The healthy growth of trees
is ensured by nitrogen fertilization. The study's objective was to
determine how different nitrogen fertilization techniques affected a
few chosen criteria. This analysis was thought to be a hazy
representation of the demands of cherries produced in herbicide
barren fields. The amount of chlorophyll in leaves, the amount of
minerals in two layers of soil, and their effects on tree growth were
all examined. The effects of nitrogen fertilizer on plant growth will
be covered in this essay.
KEYWORDS: Nitrogen, Element, Plant Growth, Development,
Environmental, Pollution, Organic, Inorganic, Fertilizers, Soil,
Leaves, Tree
How to cite this paper: Dr. Pallavi Dixit
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INTRODUCTION
Nitrogen fertilizer is necessary for many plants. Even
though soil frequently contains nitrogen and other
essential elements, it is not usually sufficient to
promote robust, long-term plant development. The
three key nutrients nitrogen, phosphorus, and
potassium are present in the majority of fertilizers,
with nitrogen playing a particular role in plant
development. And you can use a nitrogen fertilizer to
give plants the nutrition they require since they
require less phosphate and potassium than they do
nitrogen. [1]
Effects on Plant Growth:
Nitrogen helps plants grow quickly and promotes the
healthy growth of fruit and foliage when added to
garden soil. In light of this, nitrogen fertilizer is
particularly suitable for young plants that require
rapid growth in order to establish themselves in the
soil. Since lawns only have green growth and no
flowers, they also need a high-nitrogen fertilizer. [2]
Types of Nitrogen Fertilizer:
Nitrogen must be present in fertilizer in one of two
forms: nitrate nitrogen or ammonium nitrogen.
Ammonium nitrogen can be absorbed by soil particles
because it has a positive charge. Within a month of
treatment, warm soil temperatures above 50 degrees F
convert ammonium to nitrate. Because nitrate does
not adhere to soil particles and is prone to being
leached from the ground, some plants require
reapplication at different periods of the year.
Leaching describes the process by which water
pushes nutrients deeper into the soil until plant roots
are unable to access them. [3]
Urea Nitrogen:
When nitrogen is added to the soil as urea, a chain of
events is triggered. Urea nitrogen is first converted to
ammonia nitrogen by soil enzymes, which then
combines with the soil to generate ammonium
nitrogen. The ammonium is subsequently changed
into nitrate nitrogen by the microorganisms in the
soil. This procedure typically takes two to four days,
excluding cold weather that inhibits the conversions.
It may be leached from the soil after it transforms into
nitrate. [4]
Soil Acidity:
Ammonium nitrogen fertilizers steadily reduce the pH
of the soil over time, increasing its acidity. Some
ammonia solutions, such as urea, can temporarily
raise the pH of soil and even burn plant roots.
However, as the ammonia turns into nitrate, acidic
residue is created, raising the acidity of the topsoil
IJTSRD60048

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above that of the deeper soil. The top 2 inches of the
soil should be tested around every other year to
ensure that it is not too acidic for good plant growth.
If it is, the soil will need to be amended with
limestone to prevent issues from this. [5]
In South Asia, where there is a lack of arable land and
a low ratio of cultivated land to population, nitrogen
fertilizers are being used more frequently to increase
crop yields and quality. This is because there is a high
demand for food due to the region's expanding
population.
Continuous application of nitrogen fertilizers to
nonlegume crops and high application rates in some
areas have resulted in unfavorable effects, including
decreased agricultural yields and deteriorated soil and
environmental quality due to soil acidification,
nitrogen leaching, and greenhouse gas (N2O)
emissions. This chapter covers the effects of N
fertilizer on crop yields, soil quality, and
environmental safety. [6]
Nitrogen in Plants:
In the tissues found above ground, healthy plants
frequently have a 3–4% nitrogen content. Compared
to other nutrients, this concentration is substantially
higher. Only three other nutrients are found in larger
concentrations: carbon, hydrogen, and oxygen. These
three nutrients don't often play a big part in soil
fertility management schemes.
Nitrogen is essential because it is a key component of
chlorophyll, which plants utilize to convert carbon
dioxide and water into sugars during photosynthesis.
It is also a crucial part of amino acids, which serve as
the building blocks of proteins.
Plants deteriorate and perish without proteins. In plant
cells, some proteins serve as structural components,
while others function as enzymes, enabling many of
the metabolic processes that are the basis of life.
Energy-transfer substances like ATP (adenosine
triphosphate) contain nitrogen as one of their
constituent parts. Cells can store and utilize the
energy produced during metabolism thanks to ATP.
The genetic material that enables cells (and
eventually entire plants) to develop and reproduce,
nucleic acids like DNA, include a considerable
amount of nitrogen. There wouldn't be life as we
know it without nitrogen. [7]
Review of Literature:
For crop growth and output, nitrogen is a crucial
mineral nutrient (Xu et al., 2012). In order to raise
crop yields over the past three decades, N application
rates have rapidly grown and excessive amounts of N
fertilizers have been employed. Excessive N
application, however, has the potential to damage the
soil environment and cause soil acidification, which
would ultimately have a detrimental effect on crop
growth and production. [8]
As a result, crop productivity was impacted. Nitrogen
fertilizer can also change plant physiological traits as
chlorophyll concentration, plant metabolic enzyme
activity, and soluble protein levels. The amount of
leaf chlorophyll is a crucial measure of
photosynthetic capacity for assessing the N status of
plants. Key enzymes in nitrogen assimilation include
glutamine synthetase (GS) and nitrate reductase (NR).
According to Yang et al. (2004), sucrose synthase
(SS) and sucrose phosphate synthase (SPS) activity is
correlated with sink strength and crop production
when N fertilizer is used. These enzymes are crucial
for converting sucrose to starch. [9]
Fertilizing with nitrogen can have a big impact on soil
qualities. Productivity is impacted by soil variables
because they are linked to nutrient cycling in the soil
and plant nutrient uptake. Invertase, phosphatase, and
urea play important roles in the N, P, and C cycles of
soil. Different biochemical reactions in the soil are
directly impacted by these enzyme activity. Crops can
directly take nutrients from the soil, which improves
the fertility of the soil. Some significant soil
activities, including soil respiration, soil aggregate
stability, and water holding capacity, are caused by
soil organic matter (SOM). These soil characteristics
are thought to be crucial in influencing soil quality
(Gong et al., 2015). [10]
The most common agricultural chemical in the world
and a vital mineral fertilizer for plant growth and
development is nitrogen. In Turkey and other nations,
various nitrogen forms are frequently employed in the
production of vegetables. In times of rapid growth, it
plays a crucial role as a fundamental component of
protein, nucleic acids, chlorophyll, and growth
hormones. However, farmers have raised the amount
of N fertilizers they apply to their land each year
without taking into account how different species
react to varying amounts and types of N. Utilizing
fertilizers in excess beyond what the crop requires has
detrimental effects on the environment, especially
groundwater pollution and the health risks it brings,
especially when it comes to N. (2008) (Korkmaz et
al.). [11]
Objectives:
 Easy to transport, store, and apply.
 For supplying a specific nutrient, we can select a
specific fertilizer due to its nutrient specific
nature.
 Water-soluble and can easily dissolve in the soil.
Hence, they are easily absorbed by the plants.
 They have a rapid effect on the crops.

 Increase the crop yield and provide enough food
to feed the large population.
 Predictable and reliable.
Research Methodology:
This study's overall structure was exploratory. Due to
the abundant availability of N fertilizers and their
superior capacity to boost yields compared to other
organic fertilizers, including manure and compost,
nitrogen fertilization is one of the most widely
employed practices to increase crop yields
worldwide. [12] Dry matter and grain production
increased as fertilizer rates and plant population grew.
The harvest index (HI) decreased as nitrogen dosages
increased, whereas the harvest index (HI) rose as
plant population density grew. [13]
Result and Discussion:
Figure 1: Fertilizers
Fertilizers are supplied to the crops with additional
materials to boost their output. Farmers utilize these
on a regular basis to boost crop productivity. These
fertilizers include nitrogen, potassium, and
phosphorus, which are crucial elements needed by
plants. They also increase the soil's fertility and its
ability to retain water.
Types of Fertilizers:
Fertilizers are mainly classified into two main types,
organic and inorganic fertilizers.
Organic Fertilizers:
Organic fertilizers are unprocessed fertilizers that
come from plants and animals. It enriches the soil by
introducing carbonic molecules needed for plant
growth. In addition to increasing the amount of
organic matter in the soil and promoting microbial
growth, organic fertilizers can change the physical
and chemical makeup of the soil. It is considered one
of the crucial components for foods that are green.
Organic fertilizers can be obtained from the
following products:
 Agricultural Waste
 Livestock Manure
 Industrial Waste
 Municipal Sludge
Inorganic Fertilizers:
Inorganic fertilizers are those produced chemically
using processes that contain nutrients for crop growth.
The types of inorganic fertilizers are as follows:
Nitrogen Fertilizers:
Nitrogen fertilizers have the nitrogen that crops need to grow. Nitrogen, a vital component of chlorophyll, aids in
maintaining the process's balance during photosynthesis. It comprises protein and is a component of the amino
acids found in plants. Fertilizers containing nitrogen increase the quantity and caliber of agricultural output. [14]
Figure 2: Types of Fertilizers
Plant Nitrogen Needs and Uptake:
Plants can take up nitrogen from the soil as NH4+ and NO3 ions, but most of it is taken up as nitrate due to how
common nitrification is in agricultural soils. As plant roots take up water, nitrate readily travels in their direction.
Once inside the plant, NO3 is converted to NH2 and absorbed to create more advanced chemicals. In order to
allow for unrestricted uptake, a broad root system is necessary since plants require very high levels of nitrogen.

Even though the soil has an acceptable amount of nitrogen, plants with roots that are constrained by compaction
may exhibit indicators of a nitrogen shortage.
Table 1: Utilization of Nitrogen by Various Crops
Source: TFI
The majority of plants continuously uptake nitrogen from the soil throughout their lifetimes, and the requirement
for nitrogen typically rises with plant size. A plant that receives enough nitrogen develops quickly and produces
a lot of lush, succulent leaves. An annual crop, like corn, can develop to full maturity without being delayed if
enough nitrogen is present. Because it lacks the nitrogen required to produce sufficient structural and genetic
resources, a nitrogen-deficient plant often grows slowly and is modest in size. Because it doesn't have enough
chlorophyll, it typically has a pale green or yellowish hue. As the plant shifts nitrogen from less important older
tissues to more important younger ones, older leaves frequently develop necrotic and die.
On the other hand, when given too much nitrogen, some plants may grow so quickly that their ability to produce
sufficient cell walls and protoplasm is outpaced. These plants are frequently rather frail and may be vulnerable to
mechanical harm. One example of such a result is the development of weak straw and the lodging of small
grains. [15]
Fertilizer Management:
Nitrogen Cycle:
The crop to be grown, the desired yield, and the amount of nitrogen that the soil may be able to supply all
influence the nitrogen fertilizer rates. Rates required to attain various yields with various crops vary by region,
and such choices are typically based on advice and experience from locals.
Factors that Determine the Quantity of Nitrogen Supplied by the Soil:
 The quantity of nitrogen released from the soil organic matter
 The quantity of nitrogen released by decomposition of residues of the previous crop
 Any nitrogen supplied by previous applications of organic waste
 Any nitrogen carried over from previous fertilizer applications.
By assigning these variables nitrogen credits (shown in lb/acre), one can calculate their contributions. For
instance, using manure reduces the amount of nitrogen fertilizer required to achieve a specific production goal
when corn is planted after alfalfa rather than corn is planted after corn. Similar to rates, credits are typically
determined by regional factors.
More frequently, soil testing is recommended as an alternative to using nitrogen credits. The drier areas of the
Great Plains have long found it advantageous to test their soils for nitrogen, and in those areas, fertilizer rates are
frequently changed to take into account any NO3 that is discovered in the soil before planting. In the more
humid areas of the eastern United States and Canada, there has recently been some interest in testing cornfields
for NO3 using samples taken in late spring, after crop emergence, rather than before planting. This method,
known as the pre-side-dress nitrogen soil test (PSNT), has gained a lot of attention and appears to give some
insight into the necessity of additional side-dressed nitrogen.
Fertilizer Placement:
The availability of nitrogen to crops should be increased, and possible losses should be minimized. Because a
plant's roots often won't spread into another plant's root zone, nitrogen needs to be supplied in a location where

all plants can directly access it. Applications for broadcasting achieve this. When every crop row is immediately
adjacent to a band, banding is still effective. Because all rows have access to the fertilizer, banding anhydrous
ammonia or urea ammonium nitrate (UAN) in alternate row middles is typically just as effective as banding in
each middle for corn.
It is vital for nutrient uptake that the soil be moist. Because roots are more likely to locate nitrogen in moist soil
with such placement, placement below the soil surface can boost nitrogen availability under dry conditions.
When dry weather follows side-dressing, injecting UAN may result in better corn yields than surface treatment.
Subsurface placement is less important in years where there is immediate rainfall after application.
Normally, subsurface placement is employed to limit nitrogen losses. To stop the gaseous ammonia from being
directly lost through volatilization, anhydrous ammonia must be positioned and sealed below the surface. By
incorporating or injecting, one can regulate the rate of volatilization from urea and UAN solutions. In no-till
settings where volatilization is increased by significant volumes of organic material on the soil surface,
incorporation of urea materials (mechanically or by rainwater quickly after application) is especially crucial.
However, it often poses little risk to use small amounts of "starter" nitrogen like UAN in herbicide sprays.
When phosphorus and nitrogen are combined, phosphorus uptake is frequently increased, especially when the
nitrogen is in the form of NH4+ and the crop is growing in an alkaline soil. The cause of the effect is unclear,
although it could be because nitrogen increases root activity and phosphorus uptake potential, and nitrification of
NH4+ produces acidity, which improves phosphorus solubility.
Minimizing Fertilizer Losses:
Denitrification, leaching, and volatilization are the main mechanisms for nitrogen fertilizer loss. While
volatilization most frequently occurs when soils are barely moist and are drying, denitrification and leaching
occur in extremely wet soil conditions.
Practices for Avoiding Nitrogen Fertilizer Losses:
Because the hydrogen ions (H+) generated during the nitrification of the NH4+ are the primary contributor to
soil acidity, using an NH4+ source of nitrogen causes the soil to become acidic. Acidification and a decrease in
soil pH can become significant over time.
The soil becomes significantly less acidic over time as a result of nitrogen fertilizers that contain NO3 but no
NH4+, but they are typically applied in considerably less quantities than the others. Agricultural fields are
significantly acidified by NH4 nitrogen, although this acidification can be easily regulated by following standard
liming procedures.
Table 2: Acidity or Basicity of Different Nitrogen Sources

*The amount of calcium carbonate equivalent in pounds needed to neutralize the acid produced by adding one
ton of the substance to the soil is indicated by a negative sign. (Take note that if ag-lime is used, nearly two
times this amount would be needed.) The material is basic in nature when there is a plus symbol. [16]
Figure 3: Nitrogen fertilizers
One of the fertilizers that we use most frequently today is nitrogen. Fertilizer is similar to food for plants,
however nitrogen-based compounds are typically the most affordable and widely used. Depending on the crops
that are grown, nitrogen fertilizers can have a range of contents between 26% and 32%. There are various
subgroups of nitrogen compounds, including urea and ammonium nitrate. Due to the inability of legume plants
to obtain nitrogen from the soil as they would if there were no other sources, this kind of fertilizer can only be
used on nonlegume crops like corn.
A crucial essential for plant growth is nitrogen. One of the most popular forms of fertilizers used to manufacture
nitrogen so that plants can thrive and grow strongly is nitrogen fertilizer. Ammonium nitrates, urea, tetra amines,
sodium nitrate, and chloride are typical sources of plant-based nitrogen. There are also "synthetic" sources (such
monoammonium phosphate) that solely contain one form of nitrogen. [17]
Using complete dried leaves and/or fresh petiole sap, the researcher can sample the plant during the growing
season to determine its nutrient concentrations. These samples will enable the researcher to demonstrate that the
yield response was correlated with the nutritional status of the plant. Normally, soil samples are not used because
there is a possibility that a fertilizer particle may be present in the sample or because it may be unclear where to
sample if the fertilizer is delivered through a drip tape or a band. Seasonal photos are helpful for capturing both
growth and potential signs of plant deficiencies. [18]
At the proper harvest time(s), the crop response of interest—typically marketable yield—is measured. Vegetable
fruits are graded in accordance with USDA criteria to identify any fertilization-related changes in fruit quality
(size, color, sugar content, etc.). The current commercial units per area of production are used to express yields
(for example, 28-lb boxes/acre, 42-lb crates/acre, bushels/acre, tons/acre, etc.). To understand the kind and size
of the reaction, the raw data should be shown in a scatter diagram (Figure 4). Plotting the raw data enables the
researcher to look for outwardly anomalous data points that might point to mistakes made during the data
entering process.
Figure 4: Nitrogen Fertilizer Rate (Crop Yield)

Figure 4: Theoretical crop response to nitrogen fertilization (not real measured data). Each N rate was replicated
five times (some data points are obscured by others). Note the quick increase in production with the first few N
fertilization increments, followed by a leveling off and perhaps a hint of a drop in yield with too much
fertilization. Also take note that there is some output even when no fertilizer is used; in this example, it amounts
to around 20% of the maximum yield. The term "percent relative yield" will be used to describe this proportion
of the maximum yield. After 150–200 lbs./acre N, the yield seems to have plateaued. This example is provided
for illustrative purposes only; in actual field experiments, there is generally more variation between the
replications, particularly at lower fertilization rates. [19]
Conclusion:
The key nutrient that limits crop yields and quality is
nitrogen (N). N fertilizer is therefore frequently used
in enormous quantities to boost crop output all over
the world. In many developing nations, the use of N
fertilizers has enhanced crop yields and led to the
achievement of food self-sufficiency. However,
excessive N fertilizer use beyond what crops require
has had unfavorable effects, including soil, water, and
air quality damage.
References:
[1] Purdue University Cooperative Extension
Service: Types and Uses of Nitrogen Fertilizers
for Crop Production.
[2] Penn State Extension: Nitrogen Fertilizers.
[3] Sunset: Acid or Alkaline Soil: Modifying ph.
[4] University of California Integrated Pest
Management Program: Lawn Fertilizing.
[5] North Carolina Department of Agriculture and
Consumer Services: Plant Nutrients.
[6] Herrero M, Thorton PK, Noten Baert AM,
Wood S, Masangi S, Freeman HA, et al. Smart
investments in sustainable food productions:
Revisiting mixed crop-livestock systems.
Science. 2010; 327:822-825.
[7] Eickhout B, Bouwman AP, van Zeit’s H. The
role of nitrogen in world food production and
environmental sustainability. Agriculture,
Ecosystems and Environment. 2006; 116:4-14.
[8] Xu, G., Fan, X., and Miller, A. J. (2012). Plant
nitrogen assimilation and use efficiency. Annu.
Rev. Plant Biol. 63, 153–182. Doi:
10.1146/annurev-arplant-042811-105532.
[9] Yang, J., Zhang, J., Wang, Z., Xu, G., and Zhu,
Q. (2004). Activities of key enzymes in
sucrose-to-starch conversion in wheat grains
subjected to water deficit during grain filling.
Plant Physiol. 135, 1621–1629. Doi:
10.1104/pp.104.041038.
[10] Gong, L., Ran, Q., He, G., and Tiyip, T. (2015).
A soil quality assessment under different land
use types in Keriya river basin, Southern
Xinjiang, China. Soil Till. Res. 146, 223–229.
doi: 10.1016/j.still.2014.11.001.
[11] Korkmaz, K., H. Ibrikci, J. Ryan, G. Buyuk, N.
Guzel, E. Karnez, H. Oguz, T. Yagbasanlar,
2008. Optimizing nitrogen fertilizer-use
recommendations for winter wheat in a
mediterranean-type environment using tissue
nitrate testing. Communications in Soil Science
and Plant Analysis, 39: 1352–1366.
[12] Sainju UM. Cropping sequence and nitrogen
fertilization impact on surface residue, soil
carbon sequestration, and crop yields.
Agronomy Journal. 2014; 106:1231-1242.
[13] Whish MPJ, Sindel BM, Jessop RS, Felton WL,
2002. The effect of row spacing and weed
density on yield loss of chickpea. Australian
Journal of Agricultural Research, 53: 1335-
1340.
[14] Fertilizers: https://byjus.com/biology/fertilizers/
[15] Instinct is a registered trademark of Dow
AgroSciences LLC. ESN is a registered
trademark owned by Agrium Inc.
[16] Adapted from “The Efficient Fertilizer Use
Manual”, Nitrogen chapter by Dr. Don Eckert.
[17] What is nitrogen fertilizer;
https://nordfert.com/faq/what-is-nitrogen-
fertilizer.
[18] Dahnke, W. C., and R. A. Olson. 1990. "Soil
Test Correlation, Calibration, and
Recommendation." In Soil Testing and Plant
Analysis, 3rd edition, edited by R. L.
Westerman, 45-71. Madison, WI: Soil Sci. Soc.
Amer.
[19] Hochmuth, G. J., E. E. Albregts, C. C.
Chandler, J. Cornell, and J. Harrison. 1996.
"Nitrogen Fertigation Requirements of Drip-
irrigated Strawberries." J. Amer. Soc. Hort. Sci.
121:660-5.

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