Time and Methods of Fertilizer Application by Mirza Hasanuzzaman

Time and Methods of Fertilizer Application by Mirza Hasanuzzaman

Time and Methods of Fertilizer Application provides essential guidelines for effective fertilizer use in agriculture. Authored by Mirza Hasanuzzaman, this resource outlines various application techniques, including basal application, top dressing, and placement methods. It emphasizes the importance of timing and nutrient availability for optimal crop growth and environmental sustainability. The document is particularly useful for agronomy students and farmers seeking to enhance crop yield while minimizing nutrient loss. Key topics include solid and liquid fertilizer applications, foliar feeding, and fertigation techniques.

Key Points

  • Explains basal application and top dressing methods for fertilizers.
  • Covers solid and liquid fertilizer application techniques for crops.
  • Discusses the importance of timing and nutrient availability in agriculture.
  • Includes strategies for minimizing nutrient loss and environmental impact.
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for students only
1
Methods of fertilizer application
AGRO 513 Mirza Hasanuzzaman Also available at: www.hasanuzzaman.webs.com
This hand-out is not an alternative of books and class lectures. FOR STUDENTS' USE ONLY
Time and Methods of Fertilizer Application
Mirza Hasanuzzaman
Assistant Professor
Department of Agronomy
Sher-e-Bangla Agricultural University
Concept
The method of application of fertilizers (organic manure or mineral fertilizers) is an essential
component of good agricultural practices. The amount and timing of nutrient uptake depends on
various factors, such as crop variety, planting date, crop rotation, soil and weather conditions. For
good agricultural practices, the farmer chooses the timing and the quantity in such a way that as much
as possible of the nutrients is used by the plants. For optimum crop use efficiency and minimum
potential for environmental pollution, farmers must apply the nutrients as near to the time the crop
needs them as is practical. This is of particular importance for mobile nutrients such as nitrogen,
which can easily be leached out of the soil profile, if they are not taken up by the plant roots.
In the cases of urea and diammonium phosphate application, losses may occur through emission of
ammonia to the air. Both these fertilizers must be incorporated into the soil immediately after
application, if there is no immediate rainfall or irrigation to wash it into the soil. This is of particular
importance on alkaline (calcareous) soils.
All primary and secondary nutrients should be incorporated immediately after application in regions
where intense rainfall is expected, to avoid losses due to run-off and erosion.
When fertilizer is applied by hand, extreme care should be taken to distribute nutrients uniformly and
at the exact rates. Where fertilizer application equipment is used, it should be adjusted to ensure
uniform spreading and correct rates. The equipment should be well maintained.
Fertilizers are applied by different methods mainly for 3 purposes:
1) To make the nutrients easily available to crops,
2) To reduce fertilizer losses and
3) For ease of application.
The aspects that require consideration in fertilizer application are listed below:
1) Availability of nutrients in manures and fertilizers.
2) Nutrient requirements of crops at different stages of crop growth.
3) Time of application.
4) Methods of application, placement of fertilizers.
5) Foliar application.
6) Crop response to fertilizers application and interaction of N, P, and K.
7) Residual effect of manures and fertilizers.
8) Unit cost of nutrients and economics of manuring.
The time and method of fertilizer application vary in relation to
1) The nature of fertilizer.
2) Soil type and
3) The differences in nutrient requirement and nature of field crops.
for students only
2
Methods of fertilizer application
AGRO 513 Mirza Hasanuzzaman Also available at: www.hasanuzzaman.webs.com
This hand-out is not an alternative of books and class lectures. FOR STUDENTS' USE ONLY
Time of Fertilizer Application
1. Basal application
A. Before preparatory tillage: Bulky organic manures, green manures, soil amendments and soil
conditioners are applied before preparatory tillage for thorough mixing with the soil.
B. Basal dressing: Application of manures and fertilizers before last ploughing/puddling or before
sowing or planting.
C. At sowing or planting: Concentrated organic manures, readily soluble and higher mobile
fertilizers, slow release fertilizers, starter dose of N fertilizer to legume crops and fertilizer for specific
nutrient deficient soil are applied during this time.
2. Top dressing: It is the application of manures and fertilizers to the established crop within crop
duration. Top dressing may be done to the soil or to the foliage. Split application of nitrogen and
potassium is done throughout the cropping period to increase the fertilizer use efficiency.
Methods of Fertilizer Application
A. Application of fertilizers in solid form
It includes the methods like:
1. Broadcasting
Even and uniform spreading of manure or fertilizers by hand over the entire surface of field while
cultivation or after the seed is sown in standing crop, termed as broad casting.
It is suitable for crops with dense stand, the plant roots permeate the whole volume of the soil, large
doses of fertilizers are applied and insoluble phosphatic fertilizers such as rock phosphate are used.
Broadcasting of fertilizers is of two types.
Depending upon the time of fertilizer application, there are two types of broadcasting:
a) Broadcasting at planting or basal application and
b) Top dressing.
a) Broadcasting at planting
Broadcasting of manure and fertilizers is done at planting or sowing of the crops with the following
objectives:
To distribute the fertilizer evenly and to incorporate it with part of, or throughout the plough
layer and
To apply larger quantities that can be safely applied at the time of planting/sowing with a
seed-cum-fertilizer driller.
It is adopted with the following condition:
When nitrogenous fertilizers like ammonium sulphate, ammonium sulphate nitrate,
concentrated organic manures, are to be applied to the soil deficient in N or where N is
exhausted by previous crops like maize, pearl millet.
When citrate soluble phosphatic fertilizers like basic slag and diacalcium phosphate, are to be
applied to moderately acid to strongly acid soils.
When potashic fertilizers like muriate of potash and potassium sulphate are to be applied in
potash deficient soil.
for students only
3
Methods of fertilizer application
AGRO 513 Mirza Hasanuzzaman Also available at: www.hasanuzzaman.webs.com
This hand-out is not an alternative of books and class lectures. FOR STUDENTS' USE ONLY
b) Top dressing
Spreading or broadcasting of fertilizers in the standing crop (after emergence of crop) is known as
top-dressing. Generally, NO
3
– N fertilizers are top dressed to the closely spaced crops like wheat,
paddy. e.g. sodium nitrate, ammonium nitrate and urea, so as to supply N in readily available from the
growing plants. The term side dressing refers to the fertilizer placed beside the rows of a crop (widely
spaced) like maize or cotton. Care must be taken in top dressing that the fertilizer is not applied when
the leaves are wet or it may burn or scorch the leaves. The top dressing of P and K is ordinarily done
only on pasture lands which occupy the land for several years.
In some countries, aero planes are used for fertilizer application in hill terrains where it is difficult to
transport fertilizers and where large amount are to be applied because of severe deficiency and under
following situations:
Where very small quantities of fertilizers are needed over large areas. E.g.: Micro nutrients.
When high analysis materials are applied.
When fertilizer application may be combined with insect control or some other air operation
and
As a labor and time saving device.
Disadvantages of broadcasting
The main disadvantages of application of fertilizers through broadcasting are:
Nutrients cannot be fully utilized by plant roots as they move laterally over long distances.
The weed growth is stimulated all over the field.
Nutrients are fixed in the soil as they come in contact with a large mass of soil.
2. Placement
It refers to the placement of fertilizers in soil at a specific place with or without reference to the
position of the seed.
Placement of fertilizers is normally recommended when the quantity of fertilizers to apply is
small, development of the root system is poor, soil have a low level of fertility and to apply
phosphatic and potashic fertilizer.
Placement method includes (a) plough sole placement, (b) deep placement or sub-surface placement,
and (c) Localized placement or spot application
a. Plough sole placement
In this method, fertilizer is placed at the bottom of the plough furrow in a continuous band
during the process of ploughing.
Every band is covered as the next furrow is turned.
This method is suitable for areas where soil becomes quite dry up to few cm below the soil
surface and soils having a heavy clay pan just below the plough sole layer.
By this method, fertilizer is placed in moist soil where it can become more available to growing plants
during dry seasons. It results in less fixation of P & K than that which occurs normally when fertilizers
are broadcast over the entire soil surface.
b. Deep placement or sub-surface placement
In this method, fertilizers like ammonium sulphate and urea, is placed in the reduction zone as in
paddy fields, where it remains in ammonia form and is available to the crop during the active
vegetative period. It ensures better distribution in the root zone, and prevents any loss by surface
runoff. It is followed in different ways, depending upon local cultivation practices such as:
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FAQs of Time and Methods of Fertilizer Application by Mirza Hasanuzzaman

What are the different methods of fertilizer application?
Fertilizer application methods include basal application, top dressing, and placement techniques. Basal application involves adding fertilizers before planting or during tillage, ensuring nutrients are mixed into the soil. Top dressing refers to applying fertilizers to established crops, which can enhance nutrient uptake during growth. Placement methods focus on positioning fertilizers close to plant roots to improve efficiency and reduce nutrient fixation in the soil.
How does timing affect fertilizer application?
Timing is crucial for effective fertilizer application, as it aligns nutrient availability with crop growth stages. Applying fertilizers too early or too late can lead to nutrient loss through leaching or runoff, particularly for mobile nutrients like nitrogen. The document emphasizes that fertilizers should be applied as close to the time of crop need as possible to maximize uptake and minimize environmental impact.
What is foliar application of fertilizers?
Foliar application involves spraying nutrient solutions directly onto the leaves of plants. This method allows for rapid absorption of nutrients, particularly micronutrients like iron and zinc. The document highlights that foliar feeding can be especially beneficial for young plants or during periods of nutrient deficiency. However, care must be taken to control the concentration of the spray solution to avoid leaf damage.
What are the advantages of localized placement of fertilizers?
Localized placement of fertilizers ensures that nutrients are applied directly to the root zone of plants, enhancing nutrient uptake efficiency. This method reduces competition from weeds for nutrients and minimizes the fixation of phosphorus in the soil. The document outlines that localized placement promotes rapid early growth and allows for better weed control during intercultivation.
What is fertigation and its benefits?
Fertigation refers to the application of water-soluble fertilizers through irrigation systems. This method allows for precise nutrient delivery directly to the root zone, improving nutrient uptake and reducing waste. The document notes that fertigation is particularly effective for nitrogenous fertilizers, as it helps maintain optimal moisture levels while providing essential nutrients to crops.

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