Lesson 13 -Fertilising turf
There is a wide range of legislation affected by the application of fertilisers among these are;

The Health and Safety at Work Act 1974 (HASAWA) places an obligation for workers to protect themselves
and others during work operations.

The Control of Noise at Work Regulations 2005 (employees must wear hearing protection if noise level is
above 85dB.)

Provision and Use of Safe Work Equipment Regulations 1998 (PUWER) (all machinery and equipment
must be fit for use and maintained as per manufactures instructions.)

Control of Substances Hazardous to Health 2002 (COSHH) employers need to assess the risks of all
materials in the workplace e.g. fertilisers etc. and take steps to protect staff from these risks. Staff must
then comply with any protective measures identified e.g. wear protective clothing etc.

Personal Protective Equipment at work regulations 1992 (PPE) staff must be provided with and wear any
PPE required to carry out work.

Environmental Permitting Regulations (2010) the purpose of this legislation is to govern the level of
pollutants entering surface and groundwater. Pollutants could be nitrates and phosphates from fertiliser
and pesticides residue from sprayers etc. (meaning workers must take care when applying pesticides and
fertilisers near ponds, streams etc.

Manual Handling Operations Regulations 1992 requires that staff are trained to lift safely (bags of
fertiliser) and that the risks of lifting are assessed and steps taken by employers to reduce those risks for
staff
The need for fertiliser
In order for grass plants to grow well they need the correct nutrients (food) which they obtain from the soil.
Merits or Reasons for applying fertilisers to turf are:
1. Correctly fed turf will be less likely to suffer from disease and problems such as drought stress in hot
weather.
2. Correct feeding will also help ensure a good cover of grass that will resist the invasion of weeds, added
to this is the ability of healthy turf to stand up to the wear and tear caused by players and maintenance
operations such as mowing.
3. Also to be considered is that fine turf is cut on a regular basis and the clippings removed, these clippings
contain nutrients that are lost from the soil. On areas where clippings are not removed i.e. fairways, the
requirements for fertilisers will be less and on some areas such as golf roughs it is unlikely that fertiliser
will ever need to be applied at all.
The limitations of applying fertiliser
It must also be remembered that over feeding turf is more harmful than under feeding it. Too much fertiliser will
result in excessive grass growth leading to increased build up of thatch and the encouragement of weed grasses
(such as Poa annua) and turf diseases such as Fusarium patch. Also to be considered is the extra mowing time
and costs that will arise as a consequence of overfeeding turf.
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What fertilisers do plants need to grow well?
Nutrient elements obtained from the soil
(Mineral nutrients). These are taken up by the plant as its roots absorb the soil water surrounding the plant.
The Macro or Major nutrients are
Nitrogen
Phosphorus
Potassium
(N)
(P)
(K)
The three most important nutrients for grass growth are known as the Macro or Major nutrients. These are as
follows:
Nutrient
Chemical
Effect on grass growth
symbol
Nitrogen
N
Used by grass plant to grow green tissue (leaves, stems etc.)
Phosphorus
P
Potassium
K
Needed only in very small amounts that are normally available from the soil. It is
sometimes used in small amounts prior to seeding or the laying turfing as it is used
by the grass plant to promote root growth
Used by grass plant to help the grass control water loss and resist cold, disease and
wear
It is these three elements that are often shown on the front of fertiliser bags as three numbers
N
P
K
I.e.
10
6
6
These numbers refer to the percentage of the nutrient in the bag (in this bag the amount of nitrogen is 10%).
After these they are 3 three secondary macronutrients:
Sulphur
Magnesium
Calcium
(S)
(Mg)
(Ca)
Sulphur
S
Essential plant food for production of protein.
Promotes activity and development of enzymes and vitamins.
Helps in chlorophyll formation for photosynthesis
Improves root growth and seed production.
Aids vigorous plant growth and resistance to cold.
Calcium
Ca
Essential part of plant cell wall structure, provides for normal transport and
retention of other elements as well as strength in the plant.
Magnesium
Mg
Vital part of the chlorophyll in all green plants and essential for
photosynthesis. It also helps activate many plant enzymes needed for growth
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After these are the micro nutrients or trace elements
Iron
Boron
Manganese
Zinc
Molybdenum
Copper
(Fe)
(B)
(Mn)
(Zn)
(Mo)
(Cu)
Iron
Zinc
Fe
Zn
Essential for formation of chlorophyll for photosynthesis.
Essential for the transformation of carbohydrates.
Regulates consumption of sugars.
Part of the enzyme systems which regulate plant growth.
Manganese
Mn
Functions with enzyme systems involved in breakdown of carbohydrates, and
nitrogen metabolism.
Molybdenum
Copper
Mo
Cu
Helps in the use of nitrogen
Important for reproductive growth.
Aids in root metabolism and the utilization of proteins.
Boron
B
Aids the use of nutrients and regulates other nutrients.
Used in production of sugar and carbohydrates.
Needed for seed and fruit development.
However, these are only required in very small amounts and are normally available from the soil the grass is
growing in. They are not normally applied by the Greenkeeper.
Applying fertilizers - The time of year and its effects on feeding:
Most fertiliser is applied to turf is when it is actively growing, this being in the spring and summer. Fertilisers
designed to be used at this time of year will have a high nitrogen content to promote grass growth.
Some fertilisers are designed to be applied in the autumn; these are known as autumn feeds and will have a low
nitrogen content. Do not use a high nitrogen fertiliser on fine sports areas (such as golf greens) in the autumn or
winter as it may cause soft lush growth leaving the turf open to attack from the fungal disease Fusarium.
How much fertiliser should be applied per year?
There is no answer to this question, as it will depend on soil type, the grass type and the sport being played.
Fertiliser should not be used to produce colour in turf and should be applied in amounts that keep the turf healthy
and able to resist the wear and tear of play. The more fertiliser you apply the more time you will spend mowing. If
you are always removing large amounts of grass clippings and your turf is always bright green you are most likely
applying far too much!
The Sports Turf research institute has carried out research and stated that for most soil-based rootzones, an
annual application of 8 to 16 g of nitrogen per sq. metre per year (g N/m2) is adequate. This would equate to four
applications during the main growing season of 4 g N/m2. However, on sand dominated rootzones, the amount
of nitrogen applied might need to be of 24 to 30g N/m2 in the growing season.
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Fertiliser terms explained
There are many types of fertiliser available to the Greenkeeper and Groundsperson and the choice can become
very confusing, the next section will try to explain some of the terms used by producers of fertilisers.
Slow release fertilisers - these fertilisers are designed to feed the plant for a long period normally 4-8 weeks but
some types can last a complete season. The benefits of slow release fertilisers is less labour is involved as they
may only need to be applied a couple of times a year.
Controlled release fertilisers
These are similar to slow release but are designed to have a set duration of effect and can be made to release
their nutrients only under certain conditions i.e. some might only work when the soil is at a certain temperature.
Quick release fertilisers - these release their nutrients in a short period of time (i.e. 1-2 weeks), they are useful for
kick starting growth in the spring. However, they do have to be applied more often meaning more labour time and
expense.
The previously mentioned fertilisers may come in a granular/prilled form or as a powder.
Granular fertilisers are easy to handle and apply, but can take a while to work into the turf
surface (risk of boxing off when mowing).
Powder fertilisers are messy to handle and are easily blown around in the wind (often
covering the operator), however, they work into the turf surface quickly.
Prilled fertilisers
A prill is a small mix of a material, most often a dry sphere, formed from a melted liquid.
Prills are formed by allowing drops of the melted substance to congeal or freeze in mid-air
after being dripped from the top of a tall tower. Fertilizers (ammonium nitrate, urea, NPK
fertilizer) are commonly manufactured as prills. They are easy to apply and tend to spread
very evenly.
Liquid fertilisers
These are fertilisers applied to the turf in a liquid form; they are absorbed quickly by the roots or in some cases
through the grass leaves (note fertilisers designed to act in this way are known as foliar feeds).
Liquid feeds are quick and easy to apply (provided you have a sprayer) also there is less risk of scorching the turf
surface.
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Organic fertilisers
If a fertiliser is said to be organic then it is made from plants or animals that once lived (or have passed through
something that lived) examples Hoof and horn, Bone meal, Refined chicken manure.
Inorganic fertilisers
If a fertiliser is said to be inorganic then it is man made from mineral or chemical sources i.e. Sulphate of Iron,
Sulphate of ammonia, Nitram etc.
Straight fertilisers
These are fertilisers that have only one nutrient in them e.g. only contain Nitrogen etc.
Compound fertilisersThis is a fertiliser that contains a number of nutrients i.e. Nitrogen, Phosphorus and Potassium
(NPK)
Note a fertiliser may fit several of the descriptions mentioned for example a fertiliser might be described as
follows- A slow release, compound fertiliser in a granule form
Turf conditioners
Some materials are known as turf conditioners and are used to improve the grass growth, colour etc. Among the
most common are:
Sulphate of Iron
Used to improve turf grass colour (turns grass deep green, useful prior to competitions
or when colour is required without grass growth. When used Sulphate of Iron also has
the side effect that it acidifies the turf surface, which discourages worms and helps
prevent turf diseases such as fusarium patch.
Seaweed
There is some evidence that seaweed encourages microbial activity, seaweed also
contains hormones that aid root growth.
How should I apply fertiliser and what is the importance of even application?
Fertiliser needs to be applied carefully and evenly if damage to the turf surface is to be avoided, following the
steps listed below will help ensure you do not damage the grass and just as important you get even growth and
colour:
1. Always read the label and obey the instructions on the fertiliser bag, wear any personal protective equipment
required.
2. Do not apply the fertiliser if there is a strong wind blowing or heavy rain is expected.
3. Always ensure that if you are using a machine to apply the fertiliser you calibrate it first.
4. Sweep up any spills of fertiliser from the turf quickly and water the area to prevent burning of the surface.
5. Avoid getting fertiliser onto surrounding plants or water (i.e. ponds etc.).
6. Never fill the distributor on the sports surface (more chance of spilling fertiliser onto the turf).
7. Apply the fertiliser evenly by using some kind of markers; many Greenkeepers apply it in 2 directions (half the
amount each way). A trick often used is to apply in the morning so you can see your wheel marks in the early
morning dew.
8. Always wash any equipment after use as fertilisers are corrosive and may damage machinery if not removed.
9. Wash your self and any personal protective equipment worn during the work.
10. Put any fertiliser safely back into storage (a dry place away from heat and fuels).
11. Make a record what you used and where you used it.
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Calibration of distributors and applying fertiliser
It is vital that fertiliser is applied evenly to turf surfaces at the rate recommended by the manufacturer. Failure to
do this can result in:
a. Burning of the turf sward by applying too much fertilizer.
b. Inconsistent colour of the turf sward.
c. Inconsistent growth rate of grass on the treated area resulting in a poor looking surface.
d. Increased costs as more fertiliser than is needed may be applied.
Calibration of a spinning disc (cyclone type) fertiliser distributor
The information below is a guide only and you will need to experiment with each type of machine you use, if in
doubt seek advice from your supervisor.
1. Look at the fertiliser bag and find the application rate (for this example 35 grams per Meter Square (35gpm2).
2. Lay out three 1 meter square sheets of cloth on a clean workshop floor (do not use plastic as the fertiliser will
slide off the slippery surface).
3. Set the distributor to the half way mark and run it over the sheets walking at the same speed you use when you
actually apply the fertiliser to the turf
4. Weigh the material on the center mat and continue trail runs until correct amount (35g per m2 in this case) is
thrown onto the mat. Don’t forget to clean off the mats after each trail run.
Once the required amount is laid on the center mat you must weigh the material produced on the outer mats. In a
perfect world it would be half the amount of the center mat and for this example we will assume that this is the
case. Note if the machine throws wider than 3m use more mats.
For the following example we will assume a spread of 3m and an application rate of 35grams per m2.
1st run on green
17.5g
35g
17.5g
Note most of the fertiliser has fallen on center mat.
17.5g
35g
17.5g
17.5g
35g
17.5g
Operator with
machine
3m width of spread
Return run on green with overlap
ensuring even application.
Note: Some modern disk type spreaders can be adjusted to throw the fertiliser evenly across the entire width of
spread. This may remove the need to overlap. In the above example the amount of overlap required will be 1m. In
real life you will need to experiment with the machine you are using and try to get the most even application of
fertiliser possible. Often it will be impossible to get it perfect but you will get close. Once you have calibrated a
machine, record the details so you do not have to do it all over again when you next use the same fertiliser.
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Drop Spreaders
These machines are easy to calibrate as they apply fertiliser evenly along the length of spread. There fore all that
is required is the laying out of a 1m square sheet and then run the machine over the sheet ensuring the whole
sheet is evenly covered. Weigh the amount on the sheet and repeat the process adjusting the spreader until the
correct amount of fertiliser is applied to the sheet.
How to apply the fertiliser to the turf surface
Drop spreader type
Spinning disc type
Start
Start point
End
Drop spreaders are easy to use as they drop
fertiliser evenly along the length of the machine.
There is no risk of fertiliser being thrown onto
plants or ponds. However, it must be noted that
any overlap is a 100% over application and will
most likely scorch.
Note: The diagram shows a drop spreader being
used on a bowling green with 1 pass being made.
Note some turf managers make 2 passes to avoid
missing areas if this is done then it is vital to
remember to calibrate the machine to apply half of
the required application rate on the fertiliser bag.
The above diagram shows a spinning disc type
spreader being used on a golf green, marker posts
being used to help avoid missing areas. In some
cases, the posts are replaced by a fellow worker
who acts as a marker taking a set number of steps
after each run. As with the drop spreader often
two runs are made at right angles to ensure no
missed areas are left. If you choose to apply from
2 directions remember to calibrate the machine to
apply half of the required application rate on the
fertiliser bag.
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Types of equipment for applying fertiliser
Pendulum type spreader
designed for large areas.
is
The hopper holds large amounts of
fertiliser that flows to the large
pendulum that moves rapidly from
side to side throwing fertiliser
evenly onto turf surface.
Modern Scotts
distributor.
Spinning
disc
Fertiliser falls from the hopper
onto a flat disc that spins when the
machine is pushed forward.
This spinning motion throws the
fertiliser onto the surrounding turf.
These types of machines require
careful calibration as they often
require the operator to slightly
overlap each run.
Scotts Drop spreader.
These spreaders drop fertiliser off a
conveyer belt or from between
revolving rollers. The material drops
straight to the turf and so is less
affected by wind than a spinning disc
spreader.
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Understanding fertiliser, a little better
It is important that greenkeepers and grounds persons understand the basics of turf nutrition.
Fertilisers contain food for plants known as nutrients (chemicals that plants require for growth) the nutrients that
plants require most for growth are as follows:
Nitrogen, Phosphorus and Potassium (known by the elemental symbols of NPK). These are known as the Macro
nutrients.
It is the letters NPK that you most often see on the front of a fertiliser bag or a set of numbers such as 12.6.9 this
means the bag contains 12% nitrogen 6% phosphorus and 9% potassium.
Left- a typical bag of sports turf fertiliser, note the numbers 14.2.7
these refer to the amounts of NPK in the bag. As the bag contains
fairly high nitrogen rate (14%) the fertiliser is for use in the spring
or summer period. This is because the warm soil temperature will
promote good grass growth and to get the best growth the turf
will need nitrogen for green tissue growth.
Storage and transport of fertilisers
Fertilisers can present a serious fire and explosive risk.
They should always be stored well away from any sources of fire or fuel.
Fetilisers should also be kept in a dry place; if they are allowed to absorb moisture they may deteriorate and or
set as hard as concrete when they dry out making them useless.
They should be transported carefully i.e. ensure trailers etc. are loaded evenly to keep weight distributed. Ensure
they cannot slide around and become torn leading to spillage. Ensure they are protected from the rain during
transport.
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The importance of reducing waste when applying fertiliser
It is important to apply fertilisers carefully as this will help avoid waste this will
 save money
 protect the environment
Careful calibration of fertiliser distributors and careful storage of fertilisers will help reduce waste and
environmental damage.
What is the importance of checking for and clearing sports turf surfaces of debris when applying fertilisers/turf
conditioners?
The area should be checked for debris to avoid damage to the machines or turf surface. Also large amounts of
leaves on the surface may result in an uneven application of fetiliser.
How should machines and equipment be cleaned, maintained and stored securely and correctly
Equipment should be cleaned using water, compressed air etc. Heavy deposits of fertiliser will need to be
removed to prevent corrosion. Machinery should be stored with fuel turned off and any parking brakes etc.
applied. The key should be removed and stored as required. The importance of safe and secure storage is the
need to comply with health and safety, prevent accidents and vandalism.
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