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 Front Cover
 Title Page
 Table of Contents
 Introduction & Mowing
 Turfgrass cultivation
 Management practices affecting...
 Summary
 Reference
 Back Cover














Group Title: Bulletin
Title: Cultural practices for Florida golf courses
CITATION DOWNLOADS THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00008527/00001
 Material Information
Title: Cultural practices for Florida golf courses
Series Title: Bulletin
Physical Description: 19 p. : ill. ; 28 cm.
Language: English
Creator: McCarty, L. B ( Lambert Blanchard ), 1958-
Cisar, J. L ( John L )
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1991
 Subjects
Subject: Golf courses -- Maintenance -- Florida   ( lcsh )
Turf management -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 19).
Statement of Responsibility: L.B. McCarty and J.L. Cisar.
 Record Information
Bibliographic ID: UF00008527
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltqf - AAA6789
ltuf - AHZ9451
oclc - 25123977
alephbibnum - 001687427

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Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Introduction & Mowing
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Turfgrass cultivation
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Management practices affecting putting green speed
        Page 16
        Page 17
    Summary
        Page 18
    Reference
        Page 19
    Back Cover
        Page 20
Full Text










Cultural Practices for

Florida Golf Courses

L. B. McCarty and J. L. Cisar























Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida
John T. Woeste, Dean


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Cultural Practices for

Florida Golf Courses

L. B. McCarty and J. L. Cisar
























Authors
L. B. McCarty and J. L. Cisar, Extension Turf Specialists, University of Florida.







Contents
Introduction ...................................... 1
Mowing ...... ........ ...............................1
Mowing height
Mowing frequency
Mowing equipment
Reel mowers
Rotary and flail mowers
Mowing pattern
Grass clippings
Turfgrass cultivation ................ .................... 8
Aerification or coring
Benefits
Disadvantages
Soil compaction
Types of aerifiers
Core removal
Frequency of cultivation
Recent developments
Vertical grooming
Vertical mowing
Topdressing
Topdressing frequency and amounts
Topdressing materials
Management practices affecting putting green speed .......... 16
Mowing
Nitrogen fertilization
Aerification and topdressing
Brushing and combing
Water management
Summary ............... ...............................18
References and additional reading . ..................... 19








Introduction
Currently, the 1100 golf courses in Florida enjoy
heavy play and receive numerous national presti-
gious awards and recognition due to their beauty
and playability. Many environmental and man-
made variables influence the function of a golf
course. Although man has little control over
weather conditions which influence a golf course,
many cultural or management factors are control-
lable and can be manipulated to suit the needs of
the course. The objective of this publication is to
outline those culture factors which influence Flor-
ida golf courses with a special emphasis on those
which regulate putting green quality and speed.

Mowing
Mowing is the most basic yet most important cul-
tural practice a superintendent can use to provide a
desirable turf. All other cultural practices and
many aspects of turf quality are affected by mow-
ing. Density, texture, color, root development, and



BROADLEAF (DICOTYLEDONOUS) PLANT


wear tolerance are some parameters influenced by
mowing. Failure to properly mow usually results in
weakened turf with poor density and quality.

Turfgrasses can be mowed close to the ground
due to their terminal growing point (crown) being
located at or just below the soil surface (Fig. 1).
Regrowth from cell division and elongation takes
place from growing points located below the height
of the mower blade. In contrast, upright growing
dicot plants have their meristematic tissue at the
top or tip of their stems. Consequently, mowing re-
moves this growing point and many upright dicot
weeds are eliminated since they do not have
enough recuperative potential to recover.

Turfgrass growth habit is also affected by mow-
ing. Tillering following mowing increases shoot
density. However, mowing decreases root and rhi-
zome growth because food reserves, following mow-
ing, are utilized for new shoot tissue development
at the expense of root and rhizome growth.



GRASS (MONOCOTYLEDONOUS) PLANT


Fig. 1. The prostrate growing point of turfgrasses allows close mowing without permanent damage while many broadleaf plants
have their growing points elevated and are damaged from removal by regular mowing.








Improper mowing exacerbates this problem. If the
correct mowing frequency is followed, then the turf
does not go through a period of shock from the im-
mediate loss of top growth and can recover quicker.
Infrequent mowing results in alternating cycles of
elevated crowns followed by scalping, resulting in a
further depletion of food reserves.

Mowing height
Mowing heights for golf course turf is governed
by the grass being used and the use of that grass.
For example, golf greens are mowed at or below 1/4
inch to provide a smooth, fast and consistent play-
ing surface that golfers desire. In contrast, golf
course roughs are mowed between 2 and 3 inches to
penalize a player for hitting into them. Other fac-
tors that influence mowing height include mowing
frequency, surrounding shade, mowing equipment,
time of year, root growth and stress.

Mowing height refers to height of topgrowth im-
mediately after the grass is cut. Determining this
height can be misleading to inexperienced mower
operators. Often height is adjusted and checked on
a level surface such as a workers bench or roadway
and is referred to as 'bench setting'. However,
when operated, mower wheels are forced down on
grass shoots resulting in the unit riding on top of
them and the mower is actually raised higher than
the bench setting. Conversely, when a mower is
operated on soft ground or when a thick, spongy
thatch layer is present, the mower cuts lower than


the bench setting, often resulting in undesirable
scalping. Recommended mowing heights for each
grass species and use are listed in Table 1.

Many factors influence the mowing height of
grasses. Shoot tissue is the site of photosynthesis
and any removal of this strongly influences the
physiological and developmental condition of the
turfgrass plant. If grass is mowed too low or too
infrequently, crown damage can occur and exces-
sive shoot tissue is removed. This reduces the
green plant tissue left, reducing the plant's ability
to carry on photosynthesis, and results in scalped,
off-colored turf (Fig. 2). Plants mowed too low re-
quire a substantial amount of time for roots to pro-
vide food needed for shoot tissue production for fu-
ture photosynthesis. Turfgrasses have a ratio of
shoot to root tissue that is optimum to support
growing grass. If turf is mowed too low at one time,
this results in an imbalanced ratio with more roots
available to support top growth than the plant
physiologically requires. This excessive root mass
is then sloughed off. Until the plant has time to
regenerate new shoot tissue, the plant will become
weak and more susceptible to environmental
stresses.

There is also a direct relationship between mow-
ing height and rooting depth. As the mowing
height is reduced, a corresponding reduction in
rooting depth occurs (Fig. 3). This ties back into
the physiological aspect of less rooting is needed to


Table 1. Recommended mowing heights for turfgrass species and their use.
Species Use Mowing height (inches)

Tifgreen and Tidwarf Golf greens, baseball infields, 3/16* to 1/2
bermudagrass bowling alleys, tennis courts, etc.

Tifway and Tifway II Golf Tees; 1/2 to 1.0
bermudagrass Fairways, baseball outfields, 5/8 to 1 1/2
and athletic fields

Ormond and Tifton 57 Fairways and athletic fields 3/4 to 1.0
bermudagrass

Common bermudagrass Fairways, baseball outfields, 1.0 to 1 1/2
and athletic fields;
Golf course roughs 2 to 3

Bahiagrass Golf course roughs and 2 to 3
St. Augustinegrass out-of-play areas
*Mowing heights below 3/16 inch are recommended only during tournament play and only for Tidwarf bermudagrass.








support less top growth when the mowing height
is lowered. Less rooting following a lower mowing
height is why golf greens need to be watered fre-
quently, many times on a daily basis, and why
frequent fertilizer is applied since the shallower
roots have a decreased depth to obtain moisture
and nutrients from the soil. Root growth is least
affected when no more than 30 to 40% of the leaf
area is removed at one mowing.

Other influences on mowing height and fre-
quency include shade, type of mower being used,
season of year, and environmental stresses imposed
upon the grass. Under shady conditions, grass
leaves grow more upright in order to capture as
much of the filtered sunlight for photosynthesis as
possible. Mowing height for grasses grown under
these conditions need to be raised at least 30- per-
"


cent in height of that normally used in order to
capture enough sunlight to support the plants. If
mowed continuously short, grasses grown under
shaded conditions gradually thin.

Mowing height is also influenced by the mower
type being used. Rotary and flail-type mowers cut
best at heights above 1 1/2 inches. Conversely, reel
mowers cut best at heights below 1 1/2 inches.
Reel-type mowers predominate those used on a golf
course play areas while rotary and flail mowers are
used mainly in roughs and out-of-play areas.

Mowing height may also be influenced by the
season of year or by environmental stresses im-
posed upon the turf. In early spring, turfgrasses
tend to have a more prostrate decumbentt) growth
habit, therefore they can be mowed closer than
other portions of the year without serious conse-
quences. Close mowing in early spring also con-
trols thatch, increases turf density, removes excess
residues or dead leaf tissue and promotes earlier
green-up. Green-up is hastened because close
mowing removes topgrowth and dead tissue that
shades, thus cools, the soil surface. Consequently,
greater amount of solar radiation reaches the soil
surface resulting in the soil surface warming up
more quickly than if the top growth is allowed to
remain tall. In summer, when days are longer, the
grasses tend to have a more upright growth habit
and are healthier if the mowing height is raised to
compensate for it. Higher mowirng height at this


Fig. 2. Scalping results in excessive clipping debris, turf dis-
coloration and reduced rooting.


UTILITY TURF


Fig. 3. A direct relationship exists between mowing height and turf rooting. Higher mowed grass generally require less additional
watering and nutrient applications.








time also increases turf rooting, therefore, reduces
watering needs and stresses imposed by increased
nematode activity. In fall, mowing height may also
need to be raised to reduce the chance of low tem-
perature damage during winter (north Florida) and
to provide cushion for grass crowns in winter when
bermudagrass is dormant.

Mowing frequency
Mowing frequency is often a compromise be-
tween what is best for the turf and what is practi-
cal for man. Growth rate of the grass should deter-
mine frequency of cut. Growth rate is influenced
primarily by the amount and source of nitrogen fer-
tilizer applied and by season or temperature.
Higher amounts of either result in faster top
growth and an increased mowing frequency needed.
By raising the mowing height, frequency of cut is
reduced and this helps compensate for faster grow-
ing turf. The traditional rule is to mow often
enough not to remove more than one-third of
topgrowth at any one time. Removing more than
one-third of topgrowth at any one time decreases
recuperative ability of plants due to extensive loss
of leaf area needed for photosynthesis. This reduc-
tion in photosynthesis (food production) can result
in weakening or death of a large portion of the root
system since carbohydrates in roots are then used
to restore new shoot tissue. Consequently, root
growth may stop for a period since the regeneration
of new leaves (shoots) always takes priority over
sustaining roots for food reserves following severe
defoliation. However, when one-third or less of
shoot growth is removed during one mowing,
enough carbohydrates are available to simulta-
neously sustain shoot and root growth without sig-
nificantly reducing either. As an example, a golf
course rough maintained at 3 inches does not need
to be mowed as frequently (once every 10 to 14
days) compared to a golf green mowed at 1/4 inch
which requires daily mowing to prevent more than
one-third of the height being removed at any one
period (0.08 inch). In order to determine the one-
third rule, managers should mow the grass when it
reaches 50% higher than the desired mowing
height. For example, a golf course fairway main-
tained at 1.0 inch should be mowed back to 1.0 inch
when it reaches 1.5 inches. One-third of 1.5 inches
equal to 0.5 inch removed. Table 2 lists typical
mowing heights and the resulting frequency need
during active growing periods to maintain turf
within the one-third rule of thumb mowing
frequency.


Table 2. Typical mowing frequencies needed for given height
to remove one-third of the leaf surface.
Desired Height reached Approximate
height above the desired frequency
(inches) before mowing (days)

<1/4 3/8 daily

1/2 3/4 2-3

1 1 1/2 4-5

2 3 7-10

3 41/2 10-14

If turf becomes excessively tall, it should not be
mowed down to the intended height all at one time.
Severe scalping that may result can stop root
growth for extensive periods. Tall grass should in-
stead be mowed at frequent intervals and the
height gradually reduced with each mowing until
the desired height is reached. If the one-third rule
is excessively violated, the turf usually results in
gradual thinning and a disappointing reduction in
turf quality.

Mowing equipment
Mowing equipment has continued to increase in
sophistication since mowing began with a scythe.
The first reel mower was developed in 1830 by
Edwin Budding, a textile engineer, who adapted
the rotary shear that was used to cut carpet nap.
Early mowers relied on hand or animal power to
operate them. In the early 1900's, gasoline pow-
ered units became available followed by diesel pow-
ered units. Today there is a vast array of mower
types, sophistication, and costs available. When
choosing a particular model, several considerations
should be examined first.

1. The terrain to be cut. Is it smooth and level
which are more conducive for reel mowers to be
used or is the terrain rough, hilly, swampy or
wooded? These conditions may be more suited
for a rotary or flail mower.

2. The size of the area. With the ever increasing
costs related to labor, it is more practical to buy
the largest mower available to perform the job
in the shortest amount of time. There are, of
course, limits to this. For example, a weight
limit or size limit restricts the type of mower
that can be used in high maintenance areas such
as golf greens or for those areas requiring trim-
ming types of mowers.







3. Simplicity of design, durability, and maneuver-
ability. Usually the simpler the mower design,
the easier it is to operate and adjust. However,
mowers need to be versatile enough to perform
the job, such as being able to hydraulically oper-
ate individual cutting units near stationary or
unaccessible objects. Likewise, mowers should
be well-braced and ruggedly built. Maintenance
should be easily and routinely performed in or-
der to minimize the power required to operate
the equipment. Machines with easily accessible
lubrication points, adjustments of belts, bear-
ings, chains, and shafts will likely be better
maintained by employees compared to designs
which are not or require extensive effort to
reach.

4. Turf type and/or use. Several types of mowers
are available and used by golf course superinten-
dents. These include reel, rotary, and flail mow-
ers. Fine textured turf species such as bermuda-
grass or zoysiagrass should be mowed with a reel
mower. This mower provides the finest, closest
cut and is mandatory for high maintenance ar-
eas such as golf greens, collars, and tees. Turf
species with wider leaf texture such as St.
Augustinegrass or centipedegrass or upright
growing species such as bahiagrass or tall fescue
are usually mowed with a rotary mower. Most
home lawns, and low maintenance areas such as
roadsides or golf course roughs are maintained
with a rotary mower. Flail mowers are also often
used in low maintenance areas which do not de-
mand the highest quality grass.

Care of equipment once it has been obtained is
almost as important as initially choosing the right
piece. Routine maintenance such as lubrication, oil
changes, blade sharpening, tune-ups, belt adjust-
ments, and proper cleaning are important in ex-
tending the useful life of equipment as well as low-
ering operating costs. Adequate, accurate records
need to be maintained and observed to help pin-
point costs of operation and to justify purchase of
new equipment. In addition, proper storage should
be available to minimize the exposure of equipment
to weather, to prevent accidents, and to maintain
security. When a job is finished, the unit should be
properly cleaned which includes rinsing, and stored
in a clean, dry and secure area.

Reel mowers
Reel mowers consist of blades attached to a cyl-
inder known as a reel. As this cylinder rotates,


grass leaves are pushed against a sharp, stationary
bedknife and are severed. A reel mower that is
properly adjusted cuts grass as cleanly as a sharp
pair of scissors and exhibits better mowing quality
than other type of mowers. Due to this superior
cut, higher maintained turf areas such as golf
course greens, tee, and fairways as well as athletic
fields should be mowed with a properly adjusted
reel mower.

Reel mowers also require less power, consume
less fuel and, therefore, are more efficient to oper-
ate than rotary or flail mowers. Reel mowers use
up to 50% less fuel per acre of cut than rotary mow-
ers when used at the same mowing speed.

Factors influencing quality of cut of reel mowers
include the mowing height, the number of blades on
the reel, the rotational speed of the reel and for-
ward speed of the mower. At mowing heights of 1/2
to 1 1/2 inches, a reel mower typically has 5 to 7
blades per cylinder. In order to use the same
mower at a lower height of cut, the reel would have
to be powered to revolve at a higher rate of speed
than at a higher cutting height or a wavy or rippled
appearance of the turf would develop. Nine or more
blades per reel or a hydraulically-powered reel are
required at mowing heights below 1/2 inch to pro-
vide a smooth cut. Golf green mowers typically
have 11 to 13 blades on a relatively small diameter
reel in order to provide the desired smooth surface
that is required for putting.

The wavy or rippled appearance associated with
an improper mower setting or height is a result of
exceeding the designed 'clip' of the blade. The clip
is defined as the horizontal forward distance cov-
ered between the time each reel blade engages the
bedknife. This is influenced by number of blades
and rotational speed of the reel and is independent
of reel diameter. As mentioned previously, the
greater the number of blades on a reel, the shorter
the distance the mower travels before the reel
again engages the bedknife and the smoother the
resulting cut. This is also influenced by rotational
speed of the reel in relation to ground speed. A
faster rotating reel will produce a shorter clip
length than a slower reel with the same number of
blades. Usually the most uniform cut occurs when
the clip equals the mowing height. Reel mowers
that are ground-driven have a constant clip and can
only provide a smooth cut at or above a certain
height and will result in ripples when attempted to
mow below that height. This rippling also occurs








when the forward speed of the mower is excessive.
Conversely, if the clip is appreciably shorter than
the mowing height, air movement generated by the
reel prevents proper contact of grass leaves to the
reel blades and results in a ragged, nonuniform cut.
Hydraulic driven reels provide a variable clip and
usually extends the mowing height range that a
reel mower can provide.

Operating a reel mower to obtain satisfactory
results requires that the bedknife be parallel with
the reel, the reel just barely making contact with
the bedknife as it turns, and that the bedknife and
cutting edges of the reel be sharp and straight.
A properly adjusted and sharpened reel should
cleanly and easily cut a piece of paper. Adjusting
the distance between reel blades and bedknife as
well as sharpening blades by the standard process
of backlapping are used to provide this desired cut.
Backlapping involves applying a emery powder
slurry to the reel as it is rotating backward to help
maintain a sharp cut between grindings. Reel
blades should have equal contact with the bedknife
along its entire length. A clean cut, not pinched,
piece of paper should occur along at least 3 points
the length of each blade.

During operation, tight turns should be avoided
or, at least, performed slowly. When the mower
strikes turf, it has a tendency to dip and dig into
the turf. This results in the mower being depressed
on the side opposite direction of the turn. Fast,
tight turns may result in scalping or severe grass
defoliation from this dipping.

Except during periods of adjustment or sharpen-
ing, reel mowers should only be operated when in
contact with grass. The dew on and juices within
grass acts as a lubricant for the metal-to-metal con-
tact between reel blades and bedknife. If the reel is
operated during transport or over nonvegetative
surfaces such as roadways or sidewalks, heat ex-
pansion of metal may result in severe wear or
warping.

Reel mowers do have some disadvantages. Most
notably is their inability to cleanly cut grass that is
maintained above approximately 1 1/2 inches.
Similarly, tall seedheads, weeds, and tough seed
stalks are not cleanly or uniformly cut with reel
mowers. Reel mowers, especially hydraulically
driven ones, are more expensive than other mowers
and usually require a higher level of maintenance
and skill to operate and adjust.


Rotary and flail mowers
Two impact-type cutting mowers involve rotary
and flail mowers. Rotary mowers have blades that
are horizontally mounted to a vertical shaft which
cuts grass by impact at a high rate of speed. The
key to success with rotary mowers is to maintain a
sharp, balanced blade. Rotary mowers cut grass
similar to that of a machete and as long as the
blade is sharp and balanced, the quality of cut is
quite good. A dull mower blade shreds leaf blades
instead of cutting them and leaf tips become jagged
and frayed (Fig. 4). When leaf tissue is mutilated
from use of an unsharpened rotary blade, wounds
heal slowly and greater water losses occur through
evaporation since the leaf area exposed to the envi-
ronment is increased. Mutilated tissue also in-
creases the invasion points for diseases. If blades
are nicked from hitting hard objects, they should be
grounded or filed to restore the original cutting
edges.


Fig. 4. Frayed leaf tips resulting from mowing with a dull
rotary blade.

Rotary mowers have the advantages of being
relatively inexpensive and more versatile than reel
mowers. They can be used to cut very tall grass,
tough seed stalks, and weeds where reel mowers
can not. Rotary mowers are also more maneuver-
able to trim around trees and buildings than reel
mowers. Rotary mowers generally have lower ini-
tial costs and simpler maintenance requirements.
A replacement blade, for example, for rotary mow-
ers is generally much cheaper compared to a reel
mower blade.

Disadvantages of rotary mowers include their
inability to provide a quality turf at heights lower
than about 1 to 1 1/2 inch. Rotary mowers are also
dangerous in terms of hands or feet being acci-
dently placed under the mowing deck while the







blade is operating. The high speed in which blades
rotate also can be dangerous if objects such as rocks
or tree limbs are encountered. Rotary mowers are
also not usually designed to follow the surface con-
tour as exact as a reel mower. Therefore, at close
mowing heights, the rotary mower is more likely to
scalp turf as it travels across small mounds or
ridges that often compose the turf surface. All of
these characteristics combine to severely limit their
use on high maintenance turf such as golf courses
and athletic fields.

Flail mowers are another impact-type cutting
unit in which a number of small blades (knives) are
attached to a horizontal shaft. As the shaft rotates,
the knives are held out by centrifugal force. Cut
debris from flail mowers is recut until it is small
enough to escape the close clearance between the
knives and mower housing. Advantages of flail
mowers include their ability to cut tall grass into
finely ground mulch and the ability of each blade to
recoil without damage to the mower or creating a
dangerous projectile if it strikes a hard object such
as a rock. Disadvantages include the flail mower's
inability to provide a close, quality turf surface as
does a reel mower and the difficulty in sharpening
the small, numerous knives. Flail mowers are most
often used on low maintenance utility turf that is
mowed infrequently and does not have a high aes-
thetic requirement such as roughs or out-of-play
areas.

Mowing pattern
Mowing pattern imposed by operators can influ-
ence aesthetic as well as functional characteristics
of a turf surface. Aesthetic qualities are influenced
due to differing light reflections that occur in re-
sponse to mowing direction. This often results in
alternating light- and dark-green strips in response
to alternating mowing directions and are generally
more pronounced when walk-behind reel mowers
are used compared to the newer triplex-riding mow-
ers. Double-cutting at right angles produces a
checkerboard pattern on a green while alternating
mower direction every five yards on a football field
gives the appearance of light- and dark-green strips
as if two different grasses or nitrogen fertility levels
were being imposed.

Identical long-term mowing directions should not
be used even though this may produce the alternat-
ing color differences. Mowing turf repeatedly the
same direction results in grass leaning or growing
in the direction in which it is cut. This horizontal
orientation of grass foliage in one direction is called


grain. Grain results in an uneven cut, a streaked
appearance, and a poor quality putting surface on
golf greens. The ball tends to follow the grain and
when different grain is encountered, the ball reacts
by bouncing and having its path slightly altered.
Mowing continually in the same direction has the
additional detriment of scalping the same high
spots and increasing compaction and rutting by
mower wheels. Turning the mower at the same lo-
cation and in the same direction also encourages
severe wear and soil compaction.

Grain is easily prevented by varying the pattern
of successive mowings. This encourages upright
growth of the shoots which minimizes the amount
of leaf surface the rolling golf ball encounters, thus,
increases the putting speed and accuracy of the
green. Golf greens mowing patterns or directions
should be changed daily and clean-up lap reversed
or skipped on a routine basis. Often a rotating clock
pattern is followed for mowing directions and is
changed daily. Similarly, fairways should be
mowed side to side and diagonally as well as longi-
tudinally to minimize wear, compaction and grain
development.

Grass clippings
Clippings are a source of nutrients and often
compose 3 to 5% nitrogen on a dry weight basis and
also contain significant amounts of phosphorus and
potassium. If clippings are removed, this necessi-
tates the application of additional fertilizer to com-
pensate for those nutrients in the clippings. Re-
moving clippings also poses an environmental prob-
lem to many superintendents since most municipal
landfills no longer accept them, or if so, an addi-
tional fee is assessed. Emptying the catcher or rak-
ing the clippings also requires additional time and
labor. Under normal conditions, clippings should
be allowed to fall back to the turf. Only when clip-
pings are so heavy they smother the grass or inter-
fere with the playing surface, such as golf greens,
should they be removed.

By following the one-third rule on mowing fre-
quency, heavy amounts of clippings are not depos-
ited at one time and soil organisms that naturally
breakdown cellulose in grass clippings have enough
time to decompose them before accumulating.
However, if excessive growth occurs such as follow-
ing heavy nitrogen fertilization or that caused by
excessive scalping, natural decomposition may not
be able to keep up with the amount Qf clipping de-
posited. A thatch problem may develop under these
conditions.








Clippings collected from golf greens should be
disposed of properly to prevent undesirable odors
near the playing area and to prevent fire hazards
that can occur when clipping piles accumulate.
Compost piles can be developed by alternating lay-
ers of clippings with a mixture of soil and nitrogen
fertilizer. When composted, clippings can then be
used as a ground mulch in flower beds or inacces-
sible mowing areas. If not composted, clippings
should be dispersed so these piles are not allowed
to form.

Turfgrass cultivation
Heavy use areas such as golf course greens, ath-
letic fields and other turf areas often deteriorate
due to compacted soil, thatch development, and ex-
cessive use. Unlike annual crops which are periodi-
cally tilled to correct such problems, turf managers
do not have the opportunities available to provide
such physical disturbances without destroying the
playing surface. Soil related problems are usually
confined to the upper 3 inches of the turf and once
formed, may not be completely corrective where im-
proper site preparation occurred prior to establish-
ing the turf. However, over the years, a number of
mechanical devises that provide a degree of turf
cultivation with minimum disturbances to the turf
surface have been developed. Usually cultivation is
accomplished by core aerification, vertical mowing,
spiking, and topdressing.

Aerification or coring
Aerification or "coring" is the removal of small
soil cores or plugs from the turf surface, leaving a
hole in the sod. Holes are normally 1/4 to 1.0 inch
in diameter with their depth and distance depend-
ing upon type of machines used, forward speed, and
degree of soil compaction and soil moisture present.
Traditional aerifying machines penetrate the upper
2 to 4 inches of soil surface with cores spaced on
2 to 6 inch centers. Aerifiers penetrate less into
dry, compacted soils than into soils that have ad-
equate soil moisture. Characteristics associated
with coring include the following:

Benefits
1. Relieves soil compaction.

2. Allows deeper, faster penetration of water, air,
fertilizer, lime, and pesticides into the root zone.

3. Allows for atmospheric release of toxic gases (e.g.
carbon dioxide, carbon monoxide) from the root
zone.


4. Improves surface drainage to help dry out satu-
rated soils and prevent formation of puddles.

5. Improves penetration of water into dry or hydro-
phobic soils (e.g., localized dry spots).

6. Penetrates through soil layers that develop from
topdressing with dissimilar materials.

7. Thatch control by stimulating those environmen-
tal conditions which promote healthy soil micro-
organism activity which naturally decompose the
components attributing to thatch development.

8. Increased rooting by constructing an medium
more conducive for active root growth.

Disadvantages
1. Temporary disruption or damage to the playing
surfaces.

2. Increased turf surface desiccation as roots are
exposed.

3. Coring holes provide a better habitat for cut-
worms and other insects to reside.

Soil compaction
The primary goal of core aerification is to relieve
soil compaction. Compacted soil occurs when min-
eral particles have been pressed close together and
usually results from excessive or concentrated traf-
fic, especially when soil is wet. Compaction is much
more likely on fine-textured clayey soils than on a
coarser, sandy soil. Soil compaction reduces oxygen
(porosity) levels in the soil. A soil should ideally be
composed between 25 and 40% air on a volume ba-
sis but may result in as little as 5% in severely
compacted soils. Root function decreases under
such conditions due to lack of oxygen needed for
respiration and due to build up of toxic gases such
as carbon dioxide. Roots may also be unable to
physically penetrate such a tightly packed soil
mass.

Compacted soil surfaces also reduce water infil-
tration and percolation. Dry soils in compacted ar-
eas are difficult to rewet and conditions such as lo-
calized dry spots often develop, especially on high
sand content areas. On the other hand, compacted,
saturated soils may not drain excessive water and
often turn into mud with continued use. Such soils
often remain wet for extended periods of time and
become covered with an undesirable layer of algae








or moss. Success of highly maintained turf areas
such as golf greens is dependent on the superinten-
dent having control over soil moisture content of
the turf area.

Reducing or redirecting the concentration of traf-
fic is the first method of relieving soil compaction.
For example, correct placement of cartpaths and
sidewalks is important. Cartpaths should normally
be a minimum of 8 ft. wide to allow two way traffic
and larger maintenance vehicles such as trucks ad-
equate passageway. Barriers such as curbs or rail-
roads cross-tides should be used adjacent high traf-
fic areas such as tees and greens to prevent carts
straying from the path.

Traffic should also be minimized or prevented
when soil is wet. Water in soil acts as a lubricant
and traffic during these periods further aggravates
soil compaction and a resulting reduction in turf-
grass growth and vigor. Traffic should be regulated
after heavy rains as well as any mowing with large,
heavy units. Wide turf tires should be used on all
equipment to help distribute weight of such ve-
hicles over a larger area than allowed by regular
tires.

One of the most important means of preventing
soil compaction on areas receiving intense traffic,
such as golf course greens, tees, and athletic fields,
should be their construction with a predominately
sandy soil. Usually a coarse-textured soil consist-
ing of 80% or more sand is necessary to achieve
these desired results. Soils containing a significant
amount of clay or silt is unacceptable for golf green
construction and all soils should be tested before
use. Proper surface contouring and subsurface
drainage in the form of tile lines also hasten the
removal of excessive surface water.

Types of aerifiers
Many types of core aerifiers or cultivators are
available. Most fall into one of two types of catego-
ries: vertical- and circular-motion units. Minimal
surface disruption accompanies vertical-motion
core cultivators and are the preferred choice on
closely mowed turf surfaces such as golf greens
(Fig. 5). Vertical units have the drawback of being
relatively slow due to linking of vertical and for-
ward operations, however, improvement in speed
and operator ease have been achieved in recent
years.


Circular-motion cultivators have tines or spoons
mounted on a drum or metal wheels (Fig. 6). Tines
or spoons are forced into soil as the drum or wheels
turn in a circular motion. Hollow drum units are
available which remove extracted cores from the
soil surface while other units deposit cores back di-
rectly onto the soil surface. Circular-motion culti-
vators are preferred for aerifying large areas since
the rotating units can cover more ground in a given
time period than vertical-motion cultivators. How-
ever, circular-motion cultivators disrupt the turf
surface more and do not penetrate as deeply as ver-
tical-motion cultivators. Weights are often placed
on top of these cultivators to increase penetration
depth.


Fig. 5. Vertical-motion soil aerifier which minimizes surface
disruption.


Fig. 6. Circular-motion soil cultivator used for aerifying larger
areas.







Core removal
A question commonly asked is whether or not to
remove cores that result from aerifying. Cores do
not have to be removed if thatch control, temporary
compaction reduction, or air and chemical entry are
desired and the underlying soil is acceptable. If the
root-zone mixture (soil) present is acceptable then
the cores should be broken up by lightly verticut-
ting or dragging the area with a mat, brush, or
piece of carpet and the remaining debris blown off
or picked up with a follow-up mowing. Before soil
cores are matted, they should be allowed to dry
enough so they easily crumble between fingers. If
cores are too dry when matted, they are hard and
not easily broken up. If they are too wet, they tend
to smear and be aesthetically undesirable. Recent
advances in mechanization allows quick and easy
windrowing of soil cores and their subsequent me-
chanical removal. In the past, these operations
were very time and labor consuming. Following
coring, light topdressing may be needed to help
smooth the playing surface. Topdressing will be dis-
cussed later in this publication.

Frequency of cultivation
Frequency of core cultivation should be based
on intensity of traffic the turf is exposed to as well
as to the soil makeup, hardness of the soil surface,
and degree of compaction. Areas receiving intense,
daily traffic such as golf greens, approaches, land-
ing areas, aprons and tees require a minimum of 3
to 4 core aerifications annually. Additional
aerifications may be needed on exceptionally small
greens where traffic is more concentrated, areas
consisting of heavy soils high in silt and/or clay
that do not drain well, or soils exposed to saline or
effluent water use. Such areas may need aerifica-
tion with smaller diameter tines (3/8 inch or less)
every 4 to 6 weeks during the active bermudagrass
growing months. Failure to maintain an aggressive
aerification program in such situations will prob-
ably result in poorly drained soils, thin grass
stands, and continued problems with algae and
moss. Bermudagrass should only be aerified when
the turf is actively growing and is not subjected to
heat, cold and water stress. Topdressing and irri-
gation immediately following aerification may re-
duce desiccation potential, but may not be totally
effective during periods of hot temperatures. Less
intense traffic areas should be aerified on an as-
needed basis. Most golf course fairways should be
aerified twice yearly with the first timed in mid-
spring once the bermudagrass is actively growing


and the chance of a late freeze has passed. The sec-
ond aerification should be in late summer. If the
area is to be overseeded with ryegrass, then the
second aerification should be timed approximately
4 to 6 weeks prior to seeding. Aerification is not
recommended within 6 to 8 weeks before the first
expected frost in north Florida in order to allow
enough time for bermudagrass recuperation before
cold weather ceases growth.

Solid-tines are sometimes used for coring instead
of hollow-cone tines. Solid tines do not remove soil
cores and may compact soil along the sides and bot-
tom of the holes more severely than hollow tines.
The uplifting and jarring of soil using solid tines is
claimed by many manufacturers to improve soil
aeration. However, unless the soil's bulk density is
reduced by removing the soil cores, areas receiving
solid tine aerification will probably enjoy only tem-
porary benefits.

Recent developments
Two recent developments in aerification technol-
ogy involve the introduction of deep tine cultivators
(Fig. 7) that are able to extract a 3/4- to 1-inch di-
ameter core to a depth of 8- to 12-inches and the
use of high pressure water injection aerifiers. Deep
tine units enable the superintendent to relieve the
soil compaction layer that develops when tradition-
ally used aerifiers penetrate constantly to 3 inches.
Soil profiles consisting of many undesirable layers
that develop with the use of different materials for
topdressing are also penetrated. This enhances wa-
ter penetration, soil aeration and rooting. The soil
profile of an undesirable green can also be im-
proved by topdressing following deep aerification
with desirable soil.

, c- 4


Fig. 7. Deep tine aerifier which extracts soil cores 8 to 12
inches deep.







Drawbacks of deep aerification involve more sur-
face damage occurring than shallow depth models.
The initial expense also prevents many clubs from
purchasing a unit since it is more of a renovation
tool than a regularly scheduled maintenance prac-
tice. However, these units are generally available
for rent or contract use or several clubs may choose
to share the cost and use of purchasing a unit.
Care must also be used when aerifying golf greens
built to those specifications as outlined by the
United States Golf Association as not to penetrate
the 2 to 4 inch coarse sand layer that is located 12
to 14 inches deep. This would destroy the theory
behind these greens maintaining a 'perched' water
table for the turf to be grown in.

The newest aerification technique involves using
high pressure water injection. Fine streams of high
velocity water are injected over the turf surface re-
sulting in little, if any, surface disruption. Play,
therefore, is not disrupted from aerification holes
unlike traditional machines. These high pressure
units will also be beneficial in wetting hydrophobic
soils such as localized dry spots. Disadvantages are
the initial high cost, a water source must be avail-
able at all aerification sites, and effectiveness
may be reduced on heavy soils where the high pres-
sure water stream can not adequately penetrate.
Thatch control is also minimum and sand cannot be
incorporated back into the green's profile since
holes produced are not generally large enough. The
hole spacing and penetration depth is, however,
adjustable through multiple pulses, changing of
nozzle spacing, or varying speed. Water-injection
cultivation should be used as needed as a supple-
ment to traditional core aerification and not as a
replacement.

Vertical grooming
Two other cultural practices available to help re-
lieve surface compaction and promote better water
penetration and aeration are spiking and slicing. A
slicer has thin, V-shaped knives bolted at intervals
to the perimeter of metal wheels that cut into the
soil (Fig. 8). Turf is sliced with narrow slits about
1/4-inch wide 2 to 4 inches deep (Fig. 9). Slicing
can be performed much faster than coring and does
not interfere with turf use since there is no removal
of soil cores, thus no cleanup is necessary after the
operation. Slicing is also typically performed on
fairways and other large, trafficked areas during
mid-summer stress periods when coring may be too
injurious or disruptive. Slicing, however, is less ef-


fective than coring and is most effective when used
in conjunction with coring. As with coring, slicing
is best accomplished on moist soils.



2


Fig. 8. A slicer with V-shaped blades mounted on a rotating
wheel.


Fig. 9. Slicing pattern on golf greens.

A spiker provides an effect similar to a slicer but
the penetration is limited to approximately 1 inch
and the distance between perforations along the
turfs surface is shorter. Because of these reasons,
spiking is practiced primarily on greens and tees.
Solid tines are associated with a spiker and holes
are punched by forcing soil downward and laterally.
This results in some compaction at the bottom and
along the sides of the holes. A spiker is used for: a)
breaking up soil surface crusting; b) breaking up
algae layers; and, c) improving water penetration
and aeration. Since only minor disruptions of soil
surfaces occur, spiking and slicing can be per-
formed more often (e.g. every 7 to 14 days) than
core aerification (e.g. every 4 to 8 weeks).








Vertical mowing
A vertical mower has a series of knives vertically
mounted on a horizontal shaft. The shaft is rotated
at high speeds and the blades slice into the turf and
rip out thatch and other debris (Fig. 10). Different
objectives can be met with vertical mowing depend-
ing on the depth of penetrating knives. Grain of
greens is reduced when knives are set to just nick
the surface of the turf. Shallow vertical mowing
also is used to break up cores following aerification
which facilitates a topdressing effect. Deeper pen-
etration of knives stimulates new growth when sto-
lons and rhizomes are severed and results in re-
moval of accumulated thatch. Blades should be set
at a depth to just cut stolons and no deeper if new
growth stimulation is the objective. Desired depth
of thatch removal will necessitate depth that blades
are set when dethatching is the objective. The bot-
tom of the thatch layer should be reached by verti-
cal mowing, and preferably the soil surface beneath
the thatch layer should be sliced. However, there is
a limit to the depth blades should be set or exces-
sive removal of turf roots, rhizomes, stolons, and
leaf surface may occur. Vertical blade spacing for
thatch removal in bermudagrass should be between
1 and 2 inches. This range provides maximum
thatch removal with minimal damage to bermuda-
grass. Seedbed preparation prior to overseeding is
also accomplished by vertical mowing.

_.19 1 W


Fig. 10. Narrowly spaced, power driven blades of a vertical
mower used to remove excessive thatch in turf.

Deep vertical mower penetration requires the
use of a heavy-duty machine which can penetrate
2 to 3 inches. Deep vertical mowing grooves the
turf surface thereby topdressing is required follow-
ing this to smooth the surface and cover exposed
stolons. Shallow-rooted or immature turf can be
severely damaged or torn out by deep vertical mow-


ing. The turf should have some preliminary testing
at the site to be verticutted by hand pulling to mea-
sure if favorable rooting of the grass exists. Irriga-
tion and topdressing should follow such deep verti-
cal mowing to prevent quick drying out of exposed
roots, rhizomes, and stolons and to help smooth and
encourage bermudagrass recovery.

Rate of thatch accumulation dictates the fre-
quency of deep vertical mowing. Vertical mowing
should begin once the thatch layer on golf greens
exceeds 1/2 inch. This layer can be periodically
checked by using a knife to slice a plug from the
green. Areas prone to thatching may require heavy
vertical mowing several times per year. This should
begin in mid- to late-spring when bermudagrass is
actively growing and repeated 2 to 4 weeks prior to
fall overseeding. A mid-summer vertical mowing
may also be necessary. With any vertical mowing, a
30-day period of favorable growth is needed follow-
ing vertical mowing for time to recover. Therefore,
the last heavy vertical mowing of the season should
be timed at least four weeks before the first aver-
age frost (north Florida).

If the thatch layer has become excessive (> 2
inches), it may become uncontrollable by vertical
mowing (Fig. 11). In such extreme conditions, the
grass and thatch layer need to be removed with a
sod cutter and soil added to level the areas and
then is reestablished. This problem can be best
avoided by verticutting and topdressing frequently
enough to keep the thatch under control.

Interchangeable vertical mower units are now
available for many of today's triplex greensmowers.
This equipment allows for frequent vertical mowing
and simultaneous debris collect. The vertical
blades on greensmowers should be set to only nick
the surface of the turf so the surface is not im-
paired. By conducting frequent vertical mowing,
severe vertical mowing needed for renovation may
be avoided.

The grooming mower is a recent improvement in
vertical mowing. In front of the reel cutting unit of
triplex greensmowers is an attached miniature ver-
tical mower (Fig. 12). Each time turf is mowed
with this unit, the turf is lightly vertically mowed
(or groomed). This unit improves the playing sur-
face by standing up leaf blades before mowing, thus
removes much of the surface grain. New shoot de-
velopment is also stimulated by slicing stolons, and
thatch near the surface is removed.























Fig. 11. Excessive thatch layering in a golf green.


Fig. 12. Grooming unit with a grooved ('Wiehle') roller and
vertical mower mounted ahead of a reel mower unit to
slightly raise the leaf tissue for better mowing charac-
teristics.

Large turf areas are vertical mowed by using
units that operate off a tractor's power take off
(PTO). Such units have heavily reinforced con-
struction and large, thick (approximately 1/4 inch)
blades which are able to penetrate to the soil sur-
face. Vertical mowing of large turf areas such as
fairways or athletic fields are usually performed
once or twice yearly. The first is during mid- to
late-spring when bermudagrass is actively growing.
This removes thatch, and encourages turf spread by
slicing stolons and by warming the soil surface
quicker than if the thatch is allowed to remain.
A second vertical mowing is needed if fall over-
seeding is to be performed. The second vertical
mowing should be timed 2 to 4 weeks before antici-
pated fall overseeding. This discourages late-sea-
son bermudagrass growth which can compete with
the overseeded grasses, and exposes the soil surface
so overseeded grass can reach the soil better and
have optimum germination. However, fall vertical


mowing will result in a degree of surface damage
which may not heal until the overseeded ryegrass
has time to become established.

Soil and thatch should be dry when deep vertical
mowing is performed or turfgrass injury will be
more extensive since moist conditions encourage
excessive plant material to be removed. Following
all major verticutting, debris should be removed
and the area immediately irrigated. Approximately
5 to 7 days following vertical mowing one pound of
actual nitrogen per 1000 sq. ft. should be applied to
encourage rapid recovery. Quick release (soluble)
nitrogen sources are preferred.

Topdressing
Topdressing is the cultural practice that adds a
thin layer of soil to the turf surface and then is in-
corporated by dragging or brushing it in (Fig. 13).
There are many benefits to topdressing including,
increasing thatch decomposition, truing the playing
surface, reducing graininess, enhancing recovery
from injury, encouraging a denser and finer tex-
tured turf, enhancing overseeding, and modifying of
existing soil. On newly established turf, topdres-
sing partially covers and stabilizes the newly plant-
ing material, smooths gaps that result from sod-
ding, and minimizes turfgrass desiccation.
Topdressing is performed on established turf to
smooth the playing surface, control thatch and
grain, promote recovery from injury, and possibly
change the physical characteristics of the underly-
ing soil. Unfortunately, in recent years, many su-
perintendents have reduced the number of coring
and topdressing procedures due to member com-
plaints of disrupting play. These procedures, how-
ever, are sound, fundamental agronomic practices
that are necessary to maintain an optimal
bermudagrass putting surface and if eliminated,
the quality of the putting green can be expected to
diminish over time.

Topdressing frequency and amounts
Frequency and rate of topdressing depends on
the objective. Following coring and heavy
verticutting, moderate to heavy topdressing is used
to help smooth the surface, fill coring holes, and
cover exposed roots resulting from these two pro-
cesses. Irregular playing surfaces or soil profile
renovation will require frequent and relative heavy
topdressing. Rates ranging from 0.13 to 0.25 inch
(0.4 to 0.8 cubic yards of soil per 1000 sq. ft.) are
suggested (Table 3), except if the capacity of the
turf to absorb the material is limited, as grass
smothering would result.























Fig. 13. Adding a thin layer of soil by topdressing (left) and incorporating by dragging a brush over it (right).


Table 3. Approximate soil volumes needed to topdress 5000
square feet to various depths.
Topdressing depth Soil volume needed
(inches) (cubic yards)

1/32 (0.03) 0.5

1/16(0.06) 1.0

1/8(0.13) 2.0

1/4 (0.25) 4.0

1/2 (0.50) 8.0

If the objective of topdressing is to change the
characteristic of the underlying soil, then a heavy
topdressing program following numerous coring
over a period of years is required. Fine textured
soils that drain poorly are usually topdressed with
a material that is 80% or greater sand. Favorable
results are not guaranteed by this practice. How-
ever, once a material is chosen for topdressing, it is
best to stick to it. If different materials are used
for each topdressing, undesirable layers effect will
develop.

If thatch control is the main objective of top-
dressing, the amount and frequency of topdressing
is governed by rate of thatch accumulation. Thatch
layering between 0.25 and 0.5 inch on golf greens is
desirable. This relatively thin thatch layer cush-
ions (holds) the approaching golf shot better and
also provides a certain amount of protection of
bermudagrass crowns from traffic. However, once
this thickness is exceeded, frequent topdressing
along with possible coring and verticutting are nec-
essary. A suggested amount topdressing when


thatch is not excessive is approximately 1.0 cubic
yard per 5000 sq.ft. If over time this relatively
light rate is not keeping up with decomposing the
thatch layer, then frequency of application should
be shortened as well as topdressing rate increased.

If the objective of topdressing is just to provide
routine smoothing of the playing surface, then
light, frequent topdressings are suggested. Matting
the green following topdressing results in the mate-
rial being dragged into low spots. Surface irregu-
larities of the green are reduced and the area is
somewhat leveled. Topdressing with 0.5 to 1.0 cubic
yard per 5000 sq.ft. of green surface every 2 to 4
weeks provides a smoother, truer playing surface.
Light topdressing is also performed approximately
10 to 14 days prior to major club tournaments to
increase speed of greens and provide a smoother
putting surface. Frequent, light topdressing should
also be applied on new greens to cover stolons and
to smooth the surface. This should be performed
every two to four weeks until complete cover or de-
sired smoothness is achieved.

Topdressing materials
Deciding on what material will be used for
topdressing is one of the superintendents most im-
portant long-term management decisions. Using
undesirable materials can be disastrous and ruin
the integrity of many initially well built facilities.
A competent soil testing laboratory should be con-
sulted to test the sands in question to be used to
slowly change the rootzone of the green.

When the underlying soil of the playing surface
is unsatisfactory, a decision will be needed on
whether to rebuild the facility or try to slowly








change its composition through aggressive coring
and topdressing (Fig. 14). If the soil problem of the
green is considered severe, then the superintend-
ent's green's committee will probably be disap-
pointed with the coring and topdressing approach
and should consider reconstruction. If a topdress-
ing program is chosen to try to eventually improve
the soil makeup, then the next question is what
material to use. Most undesirable playing surfaces
are predominated by fine textured soils high in clay
and/or silt. The thought is to introduce a coarser
texture soil, most notably sand, to improve water
percolation and aeration. Current trends for such
situations involve frequently topdressing with 80%
or more of pure medium-fine (0.25 to 1.0 mm) sand.
This size sand is usually coarse enough to provide
the desirable effects of changing the constituent of
the soil and fine enough to be easily worked into
the turf surface but is not so fine as to seal the sur-
face and impede air and water movement.


Fig. 14. Coring holes filled with topdressing material in an at-
tempt to improve the soil characteristics of a golf green.

Some problems with topdressing with pure sand
can result. Sandy soils tend to produce harder
(firm) playing surfaces that do not hold approach-
ing shots well. Sandy soils also require an increase
in nutrient and water application since they drain
so well and localized dry spots may develop if the
sand becomes hydrophobic. Proper coring and verti-
cal mowing will help minimize some of these prob-
lems associated with high sand content soils.

Applied topdressing should be matted in by drag-
ging a piece of chain-link fence, brush, or piece of
carpet over the areas in several directions to evenly
distribute the material. This should immediately
be followed by watering to reduce drying that may
occur when the sand comes in contact with roots


exposed from the coring process and to provide fur-
ther settling of newly topdressed soil. With the in-
troduction of deep core aerifiers, changing of under-
lying soil characteristics may be expanded. Mini-
mum twice per year of using deep coring followed
by heavy topdressing with a desirable sand should
be practiced to improve poor draining greens. Be-
tween these corings, conventional aerification and
topdressing should still be performed. Over several
years, progress can be made in radically improving
the soil characteristics of the playing area by this
technique.

One of the commonly observed problems with im-
proper topdressing is the formation of various alter-
nating layers of soil. This results from using differ-
ent topdressing materials over time. Differences in
textural characteristics between these sands(s) and
organic matter layers results in miniature perch
water tables. The soil above a layer stays persis-
tently wet and root growth is restricted. Once
these layers are allowed to form, aggressive vertical
mowing and coring are required to correct the prob-
lem and this usually draws complaints from club
members due to disrupted play.

If the golf green soil is currently satisfactory,
then the topdressing material used should match it.
When new greens are constructed, stockpiling addi-
tional topsoil to cover 2 to 5 years of routine
topdressing is highly recommended to prevent in-
troduction of dissimilar soil into the green. The
only difference in the stockpiled material and regu-
lar soil mix used in construction may be the ab-
sence of organic matter in this topdressing mate-
rial. Enough organic matter is usually produced
over time by turfgrass plants to cover future needs.

Only weed- and nematode-free materials should
be used for topdressing. If the material's origin is
not known or if it has been piled and exposed for a
period of time, fumigation with methyl bromide is
highly recommended before use. Nematodes and
weeds are becoming very difficult to control with an
ever shrinking number of pesticides and re-inocula-
tion by using contaminated topdressing soil further
complicates the problem. Washed sands used for
topdressing may not need sterilization before use
but should be closely inspected to determine this.
Excess topdressing material should be properly
stored to keep it dry and uncontaminated. Covered
soil bins or polyethylene covers provide good stor-
age conditions until use.








Management practices affecting
putting green speed
Today's golf course superintendent is in the
middle of a hotly debated issue concerning the put-
ting speed of golf greens. On one hand, club mem-
bers see professional golfers playing every weekend
on the best maintained golf courses in the world.
Not a blade of grass is missing or out-of-place.
Even drainage ditches and creek banks are com-
pletely covered with lush, dark green turf. The
greens putt like glass and the pros actually com-
plain that the greens are too fast. Everything
seems to be perfect and the members have trouble
understanding why their home course can not be in
this type of condition.

However, on the other hand, the superintendent
wisely knows what is required in terms of money,
time, labor, and resources to obtain this type of
'tournament' playing condition. These courses
spend up to 5 years preparing for this one tourna-
ment and have spared no expense in achieving the
best possible playing surface. Members do not real-
ize that the greens have been pampered for months
leading up to the tournament, often not allowing
membership play during this period. The finest
equipment and supplies have been purchased and
used on the greens. Most of the greens are built to
the latest technology with the optimum components
that allow perfect soil water content control.

As with most things in life, a reasonable compro-
mise must be struck to keep the majority of mem-
bers happy yet not be so cost prohibitive. Before
using putting speed as the sole criteria for judging
the quality of a green, other components that influ-
ence this need to be discussed. A high quality
green should be uniform in terms of density and
coverage, deeply rooted, and free of disruptions
from insects, diseases, or weeds. The individual
leaves and tillers should be oriented vertically to
eliminate grain. It does not necessary need to be
dark green in color and lush in growth. A dimin-
ishing quality putting surface can be ex-
pected if speed is emphasized long-term over
other components of a good golf green.

Golf course officials should first decide on the de-
sired speed for normal play and that for tourna-
ment play. This decision should be based on the
desires of the members as well as the amount of
normal play received by the course, the superin-
tendent's knowledge and experience, money, equip-
ment and other resources the club can make avail-


able to maintain the greens. Before unrealistic
speeds are outlined by the club, reasonable expecta-
tions of the resources available to the superinten-
dent should be discussed. Grooming putting sur-
faces to maximize green speed and quality involves:

1. Mowing practices
2. Fertilization
3. Aerification and topdressing
4. Brushing/combing
5. Water management

Mowing
Many times mowing height is the only point em-
phasized as influencing the speed of putting greens.
Although mowing height is an important compo-
nent of influencing speed, it is by far not the only
component influencing this factor. If speed is at-
tempted to be maintained solely on putting height,
long-term decline of the bermudagrass can be ex-
pected.

Bermudagrass putting surfaces in Florida can
maintain everyday acceptable putting quality with
routine mowing at a height of 3/16 inch. Heights
maintained above this are healthier for the turf but
provide slower putting speeds by today's standards.
Constant mowing below 3/16 can weaken the turf
and result in some of the problems previously dis-
cussed.

Three to five days prior to a major tournament,
mowing height can be reduced from 3/16 inch to
5/32 or 1/8 inch. Tifdwarf bermudagrass is better
adapted to these lower mowing heights than
Tifgreen. Research shows that by reducing the
mowing height to 5/32 inch, an increase in putting
length is approximately 8 inches. This reduction
should occur in steps of 1/32 inch increments to pre-
vent scalping.

Research also indicates that double cutting two
days in advance of a major tournament and con-
tinuing this practice during the tournament, will
increase the putting speed approximately 6
inches. If double cutting is incorporated, it is sug-
gested that the clean-up mowing lap be made only
once since this extra lap imposes additional turning
stress on the grass and increases soil compaction.

A regular mowing schedule is also an important
mechanism in developing and maintaining a high
quality putting green. Putting green speed will be
optimized with daily mowing compared to three
times weekly. Except on the day the green is left








unmowed, research indicates that a decrease in
mowing frequency from 7 to 6 days a week will
have a very minor long term effect on mowing
speed and may encourage a healthier turf. Chang-
ing directions of cut each time also helps reduce un-
desirable surface grain and excessive wear pat-
terns.

Light, frequent vertical mowing is one of the
most beneficial grooming practices to maintain de-
sirable mowing qualities. Weekly, lightly vertical
mowing during the bermudagrass growing season
should be performed for optimum putting quality.
Vertical mower blades used on triplex mowers
should be set just above the soil surface. This shal-
low setting encourages upright, vertical growth
habit and is not intended to remove thatch from the
soil surface. If the grooves from vertical mowing
remain visible over four days, the vertical mowing
heads are probably set slightly too deep.

One relatively new improvement in mower
design is placing grooved (often referred to as
'Wiehle') rollers in front of the reels (Fig. 12).
These grooved rollers have less surface area in con-
tact with the grass, thus, do not lay the grass over
before the reel has a chance to dip the ends as do
traditional solid rollers. Grooved rollers also help
reduce thatch accumulation since they do not float
over the thatch surface, but rather, sink into it and
allow thatch removal better. The use of grooved
rollers varies between golf courses. For some,
grooved rollers are used daily, almost on a year-
round basis while for most courses, they are used
once or twice weekly. If available, grooved rollers
should be used starting several weeks prior to a
major tournament.

Nitrogen fertilization
Nitrogen is important for maintaining healthy,
aesthetically pleasing greens. Two results of nitro-
gen application are increased bermudagrass shoot
growth and wider leaf blade width. This growth in-
creases the leaf surface that comes in contact with
the ball, thus increases the resistance it must over-
come, and therefore, decreases putting green speed.
Enough nitrogen must be available to maintain a
desirable cover of bermudagrass and enable it to
recover from environmental stresses or physical
damage. However, excess nitrogen application re-
sults in many adverse conditions including a sig-
nificant reduction in putting speed. Research
indicates that for each pound of actual nitrogen
applied per 1000 square feet during the season,


approximately a 4 inch decrease in putting green
speed will result.

Under normal conditions, nitrogen applications
should cease at least two weeks prior to the start of
a major tournament. This will result in the greens
being slightly 'hungry' going into the tournament,
therefore grow slower, without significant color
loss. If unacceptable coloring of the putting surface
does occur, liquid iron application approximately
five days prior to the tournament will boost the de-
sirable dark green color of the grass without stimu-
lating excessive growth. Two ounces of iron sulfate
in several gallons of water should be applied per
1000 sq.ft. Care must be taken not to apply this
when temperatures are hot to minimize the poten-
tial of burn to the grass.

Aerification and topdressing
Aerification and topdressing are two common
and important practices necessary to maintain a
satisfactory putting surface. Each practice, as ex-
pected, has a dramatic effect on putting green
speed. Aerification not followed by topdressing has
been shown to decrease putting speed an average
of 5 inches for up to 28 days. Aerification followed
by topdressing initially decreases putting speed,
but after eight days, an increase of 6 to 15 inches
can be expected for the next 21 days for light and
heavy topdressings, respectively. Up to 8 days are
required for topdressing material to be uniformly
worked into the turf canopy and for excessive
topdressing material to be picked-up or evenly dis-
tributed by mowing.

One of the most important benefits that
aerification provides to the golfer is that it softens
the playing surface, allowing the green to hold ap-
proaching shots better. Aggressive aerification is a
must to maintain optimum bermudagrass putting
surfaces. Timing is important prior to a major
tournament. Smaller tines (<3/8 inch) should be
used for the aerification prior to the tournament
and should be timed at least 30 days prior to the
tournament. This allows time for the bermuda-
grass to recover and fill in aerifying holes. Top-
dressing should also accompany this aerification.

Topdressing also provides many attributes for
the golf green. One of its greatest is to provide a
layer of soil to smooth the small irregularities that
occur from traffic, machinery, and pest damage,
and to firm the putting surface. Light, frequent
topdressing should be applied in addition to the






42UMENT
heavier ones made after aerification. Ideally, dur-
ing the growing season, topdressing should be
made about every 2 1/2 to 3 weeks at the rate of ap-
proximately 1/8 cubic yard per 1000 sq.ft. These
light applications, especially when using dry
topdressing material, do not need to be dragged in,
but instead can be broomed in or even watered in
with the irrigation system.

As mentioned earlier, it takes approximately 8
days after topdressing for these benefits in terms of
increased putting speed to be fully recognized.
Therefore, it is recommended that a light topdress-
ing of 2 to 4 cubic ya cjlbe applied per 5000 square
feet of the green bet0e 8 and 14 days prior to the
tournament to optimize putting speed. This
topdressing should be incorporated by matting the
soil immediately after applying it by dragging a
brush, piece of carpet or chain link fence over the
surface in several directions.

Brushing and combing
Brushing one to three times per week during the
growing season with steal bristled putting green
brushes encourages vertical growth which produces
a cleaner mowing pattern and reduces grain from
lateral growth. Combing is practiced in much the
same manner and frequency as brushing.

Water management
A key to any intensively managed turf such as a
putting green or athletic field is having total con-
trol over soil water content. Excess water is often
applied to greens in an attempt to soften the soil to
hold the approaching golfer's shot, but like excess
nitrogen, wet soils slows ball roll, thus, reduces the
green's putting speed. Turf managers should at-
tempt to maintain a "soft" green by aggressive
aerification accompanied by judicious watering and
not topdressing exclusively with pure sand. Super-
intendents should water heavily to wet the entire
root zone and not water lightly on a daily basis.
Letting the soil dry between waterings will help
maintain desirable putting speed.

Summary
The following sequence of agronomic events prior
to a tournament is suggested to provide acceptable
putting surfaces in terms of uniformity, density,
and speed. If all of these are incorporated into a
total management practice package, putting char-
acteristics should be acceptable for the majority of
participants.


Six weeks prior to the tournament. Fertilize
with a 3-1-2 ratio fertilizer at the rate of 1 lb actual
nitrogen per 1000 square feet. This fertilization
will strengthen the bermudagrass for the upcoming
aerification and aid recuperation.

One month prior to the tournament. Core
aerify with relatively small (e.g., <3/8 inch) tines
when the green has adequate moisture to minimize
damage to the putting surface. Aerification is
needed when greens are considered hard and do not
hold approaching shots well or if the greens are not
allowing water to percolate internally or if localized
dry spots are developing. If these problems are not
present, then core aerification can be skipped at
this time. However, a minimum of one month will
be required for the bermudagrass to recover and fill
in the hole left from coring. Individual cores should
be removed following aerification. The exception to
this is when a desirable soil mixture is currently
present. The cores in this case should be incorpo-
rated back into the profile by lightly verticutting or
dragging with a brush or piece of carpet or chain-
link fence.

Following aerification, the greens should be
topdressed with a medium rate of desirable, clean
soil. Four to six cubic yards of material per 5000
square feet of green surface should provide a me-
dium topdressing rate. This should be immediately
incorporated by dragging. Care must be taken dur-
ing this process as not to allow excessive desicca-
tion or turf damage to occur. Irrigate heavily fol-
lowing aerification to help prevent exposed roots
from drying.

One week following aerification, greens should
receive the equivalent of 1 lb actual nitrogen per
1000 square feet as a quick release nitrogen source
(e.g., ammonium sulfate or ammonium nitrate).
Rapid release nitrogen will aid in recovery of
aerifying holes and be timed in advance of the tour-
nament so excessive growth associated with nitro-
gen fertilization will have subsided.

Two weeks prior to the tournament All ni-
trogen fertilization should be completed by this
time. If not, the grass will be growing too aggres-
sively by tournament time, and consequently, the
putting speed will be disappointingly reduced.

The greens should also be lightly vertical mowed
in two directions at this time. Vertical mowing





MARSTON SCIENCE LIBRARY


blades should just barely touch the crowns of the
bermudagrass. This will remove some of surface
debris left over from aerifying and will reduce
grain. Greens should be groomed daily at this time
by using grooved rollers, brushing and/or combing.

Between 10 and 14 days prior to the tourna-
ment, the greens should receive a light application
of topdressing. One to two cubic yards per 5000
square feet should be amble to provide the final
touches in smoothing the putting surface. The
topdressing material should be immediately incor-
porated by dragging it in several directions.

Five days prior to the tournament. If the
greens start to lose some color due to lack of nitro-
gen fertilization, then application of liquid iron
sources should be considered at this time. Two
ounces of iron sulfate or a chelated iron source in
several gallons of water should be applied per 1000
square feet. Care should be taken not to apply this
during the heat of the day.

The mowing height can be reduced at this time
from 3/16 inch to 5/32 or 1/8 inch. This height com-
bined with the other management practices out-
lined should provide satisfactory putting conditions
for the tournament.

Three days prior to the tournament. Begin
double cutting the greens at the intended tourna-
ment height. Three days are necessary prior to the
tournament before the maximum benefits from this
practice are expressed. The clean-up mowing lap
should be performed only once daily to prevent
excessive tearing of the grass or soil compaction
development.


UNIVERSITY OF FLORIDA

Sikr J. 3 1262 04969 9928
Water management during the weeks leading up
to the tournament is critical. Excessive soil mois-
ture should not be used as a method to soften the
greens. Water should be applied to wet the root
zone and soil allowed to dry before reapplying it.
However, with the added stresses of a lower mow-
ing height and double cutting, constant inspection
for wilting should occur and afternoon syringing
may be necessary.

Once the tournament is completed, the mowing
height should be raised and the greens fertilized to
aid in recovery from the concentrated tournament
play.

References and additional
reading
Beard, J. B. 1974. Turfgrass: Science and Culture.
Prentice-Hall, Inc., Englewood Cliffs, N.J.

Duble, R. L. 1989. Southern Turfgrasses: Their
Management and Use. TexScape, Inc. College
Station, TX.

Emmons, R. D. 1984. Turfgrass Science and Man-
agement. Delmar Publishers, Inc. Albany, NY.

Throssell, C. S. 1985. Management practices af-
fecting bentgrass putting green speed. Okla-
homa Turf: 3(1 and 2).

Turgeon, A. J. 1991. Turfgrass Management.
Prentice Hall, Englewood Cliffs, NJ.







DOCUMENT

























































COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, John T. Woeste,
Director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8 and June
30, 1914 Acts of Congress; and is authorized to provide research, educational information and other services only to individuals and institutions that
function without regard to race, color, sex, age, handicap or national origin. Single copies of extension publications (excluding 4-H and youth
publications) are available free to Florida residents from county extension offices. Information on bulk rates or copies for out-of-state purchasers
is availablefrom C.M. Hinton, Publications Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida32611. Before publicizing
this publication, editors should contact this address to determine availability. Printed 11/91.


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