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Group Title: Bulletin Florida Cooperative Extension Service
Title: Putting green construction for Florida golf courses
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Permanent Link: http://ufdc.ufl.edu/UF00008525/00001
 Material Information
Title: Putting green construction for Florida golf courses
Series Title: Bulletin Florida Cooperative Extension Service
Physical Description: 20 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: 1992
 Subjects
Subject: Golf courses -- 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. 18).
Statement of Responsibility: L.B. McCarty and J.L. Cisar.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00008525
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 - AAA6787
ltuf - AJE2357
oclc - 26382416
alephbibnum - 001729768

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Full Text

March 1992
March 1992


DOCUMENT


Bulletin 277


Putting Green Construction

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












Table of Contents
Introduction ........ .......... ................ 1
Initial planning com m ittee ................................ 1
Location
Drainage
Shade
Adjacent holes, houses, roads, etc
Size
Profile
Construction .................... .................... 4
Surveying and Initial Staking
Subgrade
Contours
Tile installation
Gravel and coarse sand layers
Root zone mix selection
Hydraulic conductivity
Particle and bulk density
Soil porosity
Particle size analysis
Infiltration and percolation rates
Root zone mix installation
Procedure
Building materials
Irrigation installation
Soil sterilization
Final grading
Additional information
Collars
Bunker sand
Sum m ary ................... ...... ...... ....... 17
Selected references and additional reading .................. .18
Appendix A ............ .............. .. ...... ..... 18
Darsy's Equation for Calculating Hydraulic Conductivity
Appendix B ............... .. ...................... 19
Calculating Soil Porosity
Appendix C .............................. ... .......20
Stoke's Equation for Calculating the Velocity of a
Falling Particle Through a Suspension (also referred
to as the Pipet Method)


LB. McCarty and J.L. CIsar, Turf Specialists, Department of Environmental Horticulture, IFAS, University of Florida, Gainesville









Introduction
Golf greens in the south receive heavy use
throughout the year. Many public courses receive
over one hundred thousand rounds of golf per year
with a heavily used course receiving as many as
400 rounds per day. This concentrated traffic com-
bined with daily mowing with heavy triplex mowers
almost ensures a potential for soil compaction,
especially on poorly constructed greens.

Years ago, turf was usually grown on pasture-
type soils, but as traffic intensity increased, the
usually good structure of native soils began to
break down (Fig. 1). Although the greens area of a
golf course is approximately 2 percent of the total
course area, 50 percent of the game is actually
played on these. If the desired putting surface
is not to be a mud bath, then do not choose an
ordinary soil for the root zone. A golf green
must accept and drain away excess water rapidly
and at the same time retain enough moisture to
prevent unnecessary frequent watering. The objec-
tive of this publication is to discuss the proper
sequence of construction and decision making
processes for constructing a putting green. The
following steps are a logical sequence when
formulating plans on golf green installation.

1. Initial Planning
a. Location
b. Drainage
c. Shade
d. Size and configuration

2. Construction
a. Surveying and initial staking
b. Subgrade
c. Gravel and coarse sand layer (optional)
d. Root-zone mix selection
e. Root-zone installation
f. Irrigation installation
g. Soil sterilization
h. Final grading

3. Planting and Maintenance

Initial planning committee
The most important phase of green construction
is the initial planning. As the saying goes, "plan
your work, then work your plan." Many questions
need to be addressed before construction begins on
a putting surface. A golf course planning commit-
tee should include the club's president, greens
committee chairperson, golf course architect and/or


Figure 1. Thin, undesirable turf due to excessive traffic on
greens constructed with poor soil.

club pro, building contractor, and most importantly,
golf course superintendent. Communication is the
key to success. Everyone knows how they would
like to see the proposed putting surfaces evolve and
only by having an open discussion will everyone's
wishes be heard. Several key topics that need early
priority include the following.

Location
Locating a proposed putting surface is almost as
much an art as a science. Many non-agronomic
inputs are important to provide the aesthetic back-
ground or challenging hole play to make any round
of golf a success. Natural surrounding factors, such
as a body of water, hillside or depression, overview
of a scenic area, and strategic use of natural haz-
ards such as trees, are incorporated into the loca-
tion, shape, and size of a green. Agronomic inputs,
such as surrounding soils, trees or water sources,
should also be part of this decision. The best
designed hole will only be as successful as those
factors which influence the grass's natural ability
to thrive.

Drainage
Being able to control soil moisture is the
key factor in the success or failure of a golf
green. Drainage and runoff from surrounding
areas into the desired location of a golf green can be
a key in regulating internal water content and can
be a problem especially when the green is located
downward from a hill-side location. Surface water
runoff from higher surrounding ground should not
flow over the green. Water flow from slopes should
be intercepted and redirected away from the green,
or possibly the green should be relocated. On the
other hand, greens, bunkers and surrounding
mounds should be located and shaped so that








surface water from heavy rains will drain quickly.
Positioning greens in consistently wet areas, such
as along river beds, flooded plains, and along
marshes must also be carefully planned to allow for
adequate subsurface drainage. A current trend in
the industry is to build greens elevated above the
fairway. Elevation encourages surface drainage,
helps prevent runoff from adjacent higher eleva-
tions onto the green's surface, and adds character
to the hole.

Greens that are flat, which have less than a
2-percent slope to the front of the green, generally
require extensive drainage systems. Drainage lines
should be placed every 10 to 20 feet across the en-
tire green. Greens with a 2 to 3-percent slope have
a greater proportion of excess water carried into the
front of the green. In these cases, drainage lines
are especially important in the front of the green.
In lower rainfall areas in the United States, such
greens do not need interceptor drain lines on
the back half of the green. However, in Florida,
rainfall is often heavy and these interceptor drain
lines are needed on the entire green.

Shade
Shade reduces the turfs ability to intercept the
required amount of sunlight needed to grow and
also reduces the cooling effects of airflow across the
green's surface. Full sunlight is needed to produce
food through photosynthesis, to dry out greens
after heavy precipitation, and to discourage algae
and moss buildup.

One of the basic physiological facts about
bermudagrass, is its relatively poor shade toler-
ance. This is especially true for bermudagrass
maintained under putting green conditions since
close mowing reduces the exposed leaf surface
available for photosynthesis (Fig. 2). Bermuda-
grass requires full sunlight for a minimum of 6 to 8
hours per day. In order to receive this amount of
sunlight, it is mandatory to remove all moderate to
heavy shade sources surrounding any putting
surface.

Often little foresight is used to plan for existing
trees surrounding greens. Florida is known for its
beautiful oak trees with Spanish Moss hanging
effortless in the summer breeze. However, trees
with dense canopies and golf greens do not mix.
Planning should also take into account that during
fall and winter months, the sun is lower on the
horizon than during spring and summer months.


Figure 2. Weak, thin bermudagrass resulting from exposure to
excessive shade.

Therefore, trees to the south and southwest of
greens will cast longer shadows during the cooler
months and do not necessarily need to be adjacent
to the green in order to cause shade problems. In
north Florida, shade also contributes to the poten-
tial of cold damage to the bermudagrass as frost on
shade-covered greens melts slower compared to
greens receiving full sunlight. It is suggested that
during the planning stage, the summer and winter
shade patterns for proposed golf green sites be
sketched at 8:00 a.m., 10:00 a.m., 12:00 p.m., and
2:00 p.m. to provide a blueprint of tree shade sur-
rounding a proposed or existing green site. This
sketch will allow selective trees to be removed, if
necessary, or possible relocation of the putting
green away from those areas where trees can not be
removed. If tree removal is impossible, prune as
necessary to allow for increased filtered light.


Adjacent holes, houses, roads, etc.
Another location consideration is a green's rela-
tionship to adjacent golf holes, housing develop-
ments, highways, and other high population areas.
Many times a green can be strategically placed as
to guide players away from these areas, however,
tree barriers, shrub line or even nets are sometimes
required to protect nearby personnel and property.

Size
The size of a golf green should be large enough to
allow for adequate selection of pin placement but
not so large as to become a financial and/or agro-
nomic burden. Smaller sized greens will readily
show effects from traffic concentration, while larger
ones increase maintenance costs. In general, golf
greens range from 5000 to more than 7500 square









feet. Frequently on short or narrow holes, the put-
ting surfaces are larger whereas the longer holes
have smaller putting surfaces surrounded with
more tightly positioned bunkers or other hazards,
thus requiring a more accurate shot by the player.
In order to provide a variation in challenge and
interest to the player, good design should possess
unique characteristics in size, shape, contour,
and bunker or other hazard location. However,
adequate room for necessary maintenance practices
on and around such greens require that the place-
ment of bunkers and the shaping of contours
surrounding a green insure that these operations
can be performed economically, safely, and easily as
well as be able to spread the play around the green
to prevent concentrated traffic in any one area.
The outline of any green should not contain any
sharp turns as the pressure exerted by triplex
mowers will result in compacted, worn areas.
Severe contours or mounds are also not necessary
to produce a good test of putting. Instead, they
limit cup placement and produce drought, often
scalped areas.

Profile
A number of components are used in construct-
ing golf greens. Included in these are the root
growing zone, gravel layer, sand layer and tile
lines. Several profiles consisting of some or all of
these components are successfully used. Figure 3
demonstrates the United States Golf Association's
(USGA) recommended green profile. Twelve to 14
inches of root zone medium overlay a 2 to 4-inch
coarse "choker" sand layer which covers a 4-inch


Figure 3. Cross section of an ideally built golf green with
drainage tile, 4 inches of pea gravel, a 2 to 4-inch
"choker layer," topped with 12 to 14 Inches of
proper root soil medium.


layer of gravel. Complete drainage is provided by
tile lines embedded in the gravel. These greens, if
constructed properly, have a history of providing
many years of satisfactory service and if finances
are not limited, this type green profile probably
provides the best chance of long-term success.
However, if the specifications of this green are
strictly adhered to, the raw materials are often dif-
ficult and expensive to obtain and the expertise and
care required in construction are very demanding.


Figure 4. Cross section of an acceptable bermudagrass golf
green with proper sized pea gravel and without the
2 to 4-inch "choker" layer.




.



12-14 .
inches :::
of sand '. .
S compacted
p -.;:parent soil or
6- f mil plastic



2-4 inch 4 inch
drain line '.. pea gravel


Figure 5. Profile of an alternative method of green" construc-
tion that eliminates the 4-inch "pea" gravel layer and
2 to 4-inch coarse sand (e.g., "choker") layer. Note
the need to still use pea gravel to fill drainage line
ditches.








For those clubs limited in financial resources,
other green profiles are available and successfully
used. Figures 4 and 5 offer two such examples of
alternative green profiles. The profile outlined in
Figure 4 is recommended over Figure 5. It
consists of a 12 to 14-inch root zone profile over a
4-inch gravel layer with tile lines embedded within
the gravel. This profile is identical to Figure 3 but
lacks the 2 to 4-inch choker sand layer. Although
the basis of the choker layer is theoretically sound
in that it provides a perched water table, in prac-
tice this principle is used very little. The choker
layer's absence can be overcome by selecting the
proper sized gravel in relation to the root zone.

For those golf courses with limited resources but
wish to have improved greens, Figure 5 offers a
profile with the minimum construction require-
ments for golf greens in Florida. It consists of 12 to
14-inches of root zone. Tile lines underneath are
trenched into the subgrade and filled with gravel.
Unlike the previous mentioned profiles, the 4-inch
gravel layer is deleted as is the 2 to 4-inch choker
sand layer associated with the USGA profile. The
planning committee should consider all three green
profiles and weigh the benefits of each against their
negative points. Generally, better results can be
expected from those greens constructed in Figures
3 and 4 but due to financial restraints, Figure 5
may be a suitable alternative.

Construction
Successful golf green construction is dependent
upon the quality of the planning phase and
persons) responsible for implementing the plan.
Usually green construction is the most time-con-
suming and costly procedure when building a golf
course because of extensive excavation and restruc-
turing of the area. After the design of the greens
has been agreed upon by the planning committee,
construction steps involve: (1) professional survey-
ing and staking of the green area; (2) shaping and
compacting the sub-grade and grading the sur-
rounding area; (3) installing subsurface drainage;
(4) placement of the gravel layer; (5) off-site mixing
of root zone mix and its subsequent placement; (6)
irrigation system installation; (7) soil sterilization;
and, (8) settling and finish grading prior to plant-
ing. Cutting corners and time in green construc-
tion usually results in long-term disenchantment
by the club members and increased long-term
maintenance for the superintendent.


Surveying and initial staking
The architect provides a detailed plan drawn to
scale on how the intended green is to be sloped and
shaped. A competent, licensed surveyor usually
is responsible for ensuring that this work is in
accordance to the architect's wishes. A permanent
bench mark (permanent elevation point) must
first be established from which all elevation adjust-
ments are made. Bench marks are usually cen-
tered in the golf course construction site. However,
uneven terrain or unavoidable obstacles may neces-
sitate several bench marks to be used throughout
the course. Once the bench mark is established
and identified, the perimeter of the putting green is
staked at intervals of every 15 to 25 feet using the
fairways centerline reference stake plus the eleva-
tion difference from the bench mark. The purpose
of the perimeter stakes are to identify the outline of
the green's shape and provide initial surface con-
tours according to the architect's drawings. These
stakes should be properly coded (e.g. colored) and
identifiable in order to facilitate the operations
with minimum chance of errors.

Subgrade
Contours
A key to good green construction is a properly
planned and constructed subgrade. Internal drain-
age follows the contours of the subgrade as well as
the final surface grade since it is identical to the
subgrade. When deciding on the green's configura-
tion, it is advised that under normal circumstances,
contours should not be sloped towards the front of
the green since this is the point of entrance and
exit of much of the traffic. A wet front exposed to
concentrated foot traffic normally results in thin,
worn areas. It is better to have the green's slopes
draining away from high traffic areas and from any
side that faces the cart path's entrance and exit.

Depending on the design of the green and eleva-
tion of the site, the subgrade will be built into the
existing grade or cut into the subsoil. If the grade
is to be cut into the subsoil, topsoil that is stripped
may be stockpiled for future building of adjacent
elevations (such as mounds) or distributed over the
fairway or rough. Usually, greens built into the
existing grade are elevated, requiring outside fill
material for the subgrade. Heavier soils, such as
clays, are desirable for a subgrade since these are
easily compacted to form a firm base that does not
readily shift or settle. In either case, the subgrade
fill material must be compacted to prevent future








settling which might create depressions resulting
in pockets of poor drainage or, in the event of
higher finish grade, drought areas. The best
device to accomplish this is a power driven vertical
compactor (modified jack-hammer) or, as a second
choice, a water filled mechanical roller operated in
several directions across the subgrade floor.

In order to form a uniform root zone depth
throughout the green, contours of the subgrade
should match those of the finish surface grade with
a tolerance of inch. Initial shaping of subgrade
contours involves placement of fixed grade stakes
that are referred to the permanent bench mark
elevation. The bulldozer operator then follows
these pre-marked stakes to the indicated depths
that the architect intended. Once the operator is
finished with the initial contours, they should be
resurveyed to ensure that the settled contour
elevations are as originally specified. Usually the
architect then inspects the subgrade contours to
ensure that they meet the original specifications
and to allow for any slight modification to improve
them.

Tile Installation
Providing the desired drainage for golf courses
includes proper tile drain line installation. Tile
installation is imperative for water removal if the
subgrade is a clay or if the soil has a impermeable
layer, otherwise the green could remain excessively
wet for several days after heavy rain.

The first phase of tile installation involves loca-
tion of an adequate-sized outlet for drainage water.
Typically, tile lines are drained into nearby ditches,
ponds, large drainage lines, existing french drains
in the fairways, or nearby out-of-play grass areas.
Discharge lines should be nonperforated pipe and
not be laid straight down a steep slope, but have a
gradual slope to reduce the flow rate from the
green. In some cases, a suitable discharge source
may not be readily available. In this case a sump
and pump may be required. The sump is a water
gathering area (tank) such as that formed when
several concrete rings are placed on top of each
other enclosed with a lid. A low-lift pump is
installed inside the sump with float-activated
switching so that the water level may be controlled
within specified limits. Once this predetermined
level of water is drained into the sump, the dis-
charge water is then pumped up to an appropriate
discharge area. Sumps should be located away
from the green and in areas receiving little traffic.
Care must be taken not to direct the green's main


drainage lines into adjacent sandtraps as washouts
will be common. Covering the main tile line outlet
with a mesh wire is also advisable to prevent
rodents from entering the lines and tunneling up
into the green.

Drainage lines should be spaced so water will
not have to travel more than 10 feet to reach any
one line (e.g., tile lines 15 to 20 feet apart). If the
golf green is situated on an area with a high water
table, larger tile lines placed deeper into the
subgrade soil profile may be necessary to lower the
water table and to handle the increased internal
amount of water.

Typically, a gridiron or herringbone arrange-
ment is designed for the tile outlay in which they
are diagonally to the grade (Fig. 6). However, any
shaped tile arrangement is acceptable as long as
each line has a continuous downward slope and
water does not have to travel significantly more
than 10 feet to a drain line. Greens with slopes
greater than 2 percent or have surface water runoff
from high surrounding ground should have an in-
terceptor drain line that rings the inside diameter
of the green, especially in the front or lowest area
(Fig. 6). This helps prevent water accumulation
in the front portion of the green where players
typically enter.

In the past, drain line tiles consisted of agricul-
tural clay tile, concrete, or flexible, corrugated


Figure 6. Typical pattern for drainage tile installation In golf
greens so that water will not have to travel In excess
of 10 feet and the recommended "ringing" a green
with drainage line when slopes are greater than 2
percent or surface water runoff from higher sur-
rounding ground occurs across the green's surface.























Figure 7. Plastic corrugated tile used widely for providing
Internal golf green drainage.

plastic. Two to 4-inch diameter corrugated, flex-
ible, plastic tile with slits is widely used today due
to its ease of installation and relatively low cost
(Fig. 7). Slits of the plastic tile should always be
laid facedown on the gravel bed to prevent clogging
of lines by soil migrating downward. Nylon-netted
filter drain sleeves which wrap the tile line are
available. However, if silt and clay content from
the topsoil exceeds 5 to 10 percent total, these may
plug up.

Trenches in which drainage lines are laid should
be dug 6 inches deep into the subgrade and be 5 to
6 inches wide (Figs. 3, 4, and 5). Up to 12-inch
wide trenches are sometimes used, however, this
wider cut necessitates more gravel, thus higher
costs, to fill the trench. Normally, the trench width
and depth should be no greater than twice the size
of the drain line. A 5 to 6-inch wide box-shaped
trench will allow a 0.5 to 1 inch gravel bed below,
above, and on either side of a 4-inch drain line.
The soil from digging the trenches should either be
removed or placed between drainage lines to
provide a slight crown and compacted.

Before trenching, the area should be surveyed
and staked with proper labeling for the desired
depth of cut. Tile should not be placed deeper than
is necessary to obtain the desired amount of slope.
Grade stakes should be placed to give tile lines a
minimum downward slope (fall) of 0.5 percent
(1 ft in 200 ft), ideal of 1 to 2 percent (1 ft in 100 ft
or 1 ft in 50 ft) and a maximum slope of 3 to 4
percent (1 ft in 33 ft to 1 ft in 25 ft). Slopes less
than 0.5 percent are difficult to properly install and
maintain and also drain much slower than steeper
ones. Slopes greater than 3 to 4 percent will loose


lateral drainage capability, require greater eleva-
tion changes within the drain line, and a deeper
outlet point. Care must be taken to ensure that the
trench and tile are always sloping downward so
pockets of standing water do not develop. These
lines should be placed diagonally to the slope of the
green and not at right angles. All main and lateral
lines should be double checked with a level prior to
backfilling to insure that the grade provides desired
drainage. Tile joint tops should be covered with
asphalt paper, fiberglass composition or with
plastic spacers or covers to prevent gravel and
sand from entering the line.

It is recommended that the main drainage line,
into which the lateral (feed) lines flow, have its
upper end extended to the soil surface and properly
capped. In the future, if this line becomes contami-
nated (clogged) with soil, the cap can be removed
and the line flushed. This greatly extends the use-
ful life of the drainage system without need of dis-
turbing the playing surface to clean the tile lines.

After tile installation, the surveyor should place
grade stakes into the subgrade throughout the
putting green site (Fig. 8). With allowance for the
depth needed to drive the stakes into the ground,
each stake should be marked at 4 inches, 6 to 8
inches, and 18 to 20 inches above the subgrade.
These markings correspond to the intended depth
of the gravel, coarse sand layer (this layer is
optional, see below for further details) and root
zone layer required in the green profile. Stakes
should be placed at frequent spacing throughout
the putting green site to indicate any changes in
elevation or contouring of the surface.


,.~ r


-I U
Figure 8. Grade stakes placed into the subgrade to mark the
intended depth of the green's gravel and root zone
layers.


U


---u


a;-









Gravel and coarse sand layers
After tile installation is completed, the subgrade
bed should ideally be covered with 4 inches of
gravel (Figs. 3 and 4). This gravel layer serves
several purposes: (1) it is the transport medium
from which infiltering water can move vertically to
tile lines; (2) it is a buffer between the moist root
zone medium and dry subgrade soil which prevents
the dry subgrade soil from extracting water from
the root zone; (3) it prevents salt movement from
the subsoil into the root zone (Near the coast,
where the water table may have salt intrusion,
these salts can move to the soil surface through the
process of evaporation during periods of hot, dry
weather.); (4) the gravel along with the tile, helps
prevent excessively wet root zone due to a rising
water table; and, (5) depending on the soil mix
above it, the gravel may provide the abrupt change
in particle size from the finer texture root zone mix
that is needed to provide the perched water table
which increases water holding capacity of the root
zone mix.

Alternative green construction has been success-
fully achieved by eliminating the 4-inch pea gravel
layer but not the need to fill the drainage ditches
with gravel (Fig. 5). If this profile is chosen, the
parent subgrade soil must be compacted and/or a
6-mil plastic layer used to separate the root zone
medium from the subsoil. It is recommended that
golf clubs with adequate financial resources not
eliminate this 4-inch gravel layer since it ensures
a greater probability of success.

One question that needs to be addressed early in
the planning stage is the type of root zone mix that
is going to be used as this will affect the type of
gravel used. If the main objective is to remove
water as quickly as possible from the root zone,
then a predominately coarse-textured sand should
be used and the gravel should be no larger than 1/4
inch (6 millimeters), e.g., "pea gravel." If the objec-
tive of the root zone mix is not to remove water as
quickly as possible but rather encourage water and
nutrient retention, then gravel sized up to 0.4 inch
(10 millimeters) may be used. In theory, if the
change in size from the overlying root zone is no
greater than 6 to 7 times the diameter of the gravel
used, then the smaller sand and soil particles from
the overlying material will not wash into the gravel
and reduce drainage. For example, if 1/4-inch (6
millimeters) pea gravel is used, then the majority of
the overlying material should be equal to or greater
than approximately 1/24 inch (1 millimeter). If the
majority of the soil mix is less than 1 mm, then


clogging of the larger gravel drainage pores may
result. If coarse stone (1 inch) is used to fill the
drainage trench, then a level of pea gravel would
be needed to bring the subgrade up to 4 inches to
prevent movement of smaller particles from the
overlying layer into the underlying larger stone.

Superintendents should also be careful in the
gravel source they choose. Granite gravel is best
since it is rigid and less likely to be crushed. Softer
gravel sources such as calcium carbonate rock may
break down over time due to the weight of the
overlying soil and to chemical reaction with acidic
water.

If 1/4-inch pea gravel is not available, then on
top of the gravel layer is placed an evenly distrib-
uted two to four inch coarse sand layer (;0.5 mm).
This coarse sand layer is commonly referred as the
"choker" layer (Fig. 3). The "choker" layer acts as a
barrier to prevent soil particles from the root zone
mix from migrating downward into the gravel. It
also creates a perched water table. If pea gravel is
available and the root zone particle size conforms to
those limits discussed above, then this layer of
coarse sand is not necessary (Fig. 4). Normally, it
is cheaper and easier to use correct-sized pea gravel
alone compared to using a "choker" layer since this
layer must by evenly spread by hand labor instead
of a machine. The operator of a tractor or bulldozer
will have difficulty uniformly spreading this two to
four inch layer of sand and there is a chance this
heavier equipment may crush the underlying
drainage tile.

A topic which is currently receiving much atten-
tion is the possible substitution of the coarse sand
"choker" layer with a non-biodegradable woven
filter fabric. There is considerable debate between
soil scientists as to whether or not this man-made
fabric is a viable option. In the past, especially
with earlier attempts, fabric clogging commonly
resulted within a year or two of installation. How-
ever, as newer and improved materials are devel-
oped, this clogging problem may be eliminated,
especially if the silt and clay content of the root
zone mix is less than 5 percent. Until scientifically
tested and proven results are available (preferably
several times at several universities), a recommen-
dation cannot be made.

Root zone mix selection
Above the gravel or coarse sand layer is placed
12 to 14 inches of laboratory tested root zone mix.
In earlier days the most used method of green








construction was where a bulldozer operator
pushed up the surrounding soil into a final grade
and grass was planted. Over time, however, as
traffic and watering demands increased on these
greens, superintendents began having trouble
maintaining a desirable putting surface without
the green holding too much water, or becoming too
dry, or excessive disease outbreak, particularly
Pythium and fairy ring. Similar negative results
also occur if the soil used contained excessive ani-
mal manure. Today, agronomists recognize that
choosing a proper root zone mix is the most impor-
tant decision when constructing golf greens.

Since the 1940's, numerous studies have investi-
gated better methods of building golf greens; e.g.,
ones that would drain adequately, yet, not drain so
well that nutrients and moisture content were diffi-
cult to maintain. These studies have consistently
shown that materials used for green construction
should be a coarse-textured (sandy) material. All
sands are not created equal. Some sands are better
suited for constructing golf greens while others are
better for making concrete or providing a road bed.
In general, standard builders' sand used for
construction or for concrete mixing are not
suitable for golf green construction. These
sands are either too coarse, thus remain drought,
or have a broad range of particle-size distribution,
making the sand dense and impermeable. These
sands become very compact with the introduction of
even a small percentage of silt and clay. Table 1
represents the United States Department of Agri-
culture (USDA) particle size classification for those
materials of general interest for building the root
zone of desirable putting greens. Some sand
companies provide particle-size distribution but in
many cases the analysis is based on engineering
criteria, not the USDA sieve sizes.

Many golf courses do not plan nor take the time
to sample different root zone materials to deter-
mine the best possible mix for their particular loca-
tion. A proper soil mix should be identified by soil
laboratory testing. Only a reputable, reliable
soil testing facility should be considered
when trying to determine the best root zone
mixture for a particular location. Before
choosing a soil-testing laboratory, two criteria
should be investigated: (1) the experience/reputa-
tion of each lab; and, (2) the sample turnover rate
that the laboratory can provide. Many labs are
available but only a few have the field experience in
addition to the "book" learning, specifically in turf.
If the laboratory personnel do not have specific turf


Table 1. Particle size classifications as determined by the
United States Department of Agriculture.
U. S. Standard Sieve Opening
Textural Name (sieve number) (millimeters)
Gravel 4 >4.76

Fine gravel 10 2.00-4.76

Very coarse sand 18 1.00 -2.00

Coarse sand 35 0.50-1.00

Medium sand 60 0.25-0.50

Fine sand 140 0.10-0.25

Very fine sand 270 0.05-0.10

Silt 0.002-0.5

Clay <0.002


experience, then they may not understand the total
concept and specific goals of turf managers.
Random samples of the root zone components and
proposed mixes need to be made to ensure that the
sample specifications do not change as different
areas or sources are used to obtain the root zone
mix components. In the past, sand specifications
have differed as changes in the various depths of
the pits occurred or when adjacent pits were used.
Without quick turn around by a laboratory,
contractors and suppliers will be held up, causing
confusion and anger.

Once representative samples (e.g., a minimum of
2 gallons of sand and 1 gallon each of soil, organic
matter, and gravel) are received, the soil-testing
laboratory will analyze the physical characteristics
of each component to determine the best proportion
for the root zone mix. Included in the analysis are
saturated hydraulic conductivity (infiltration and
percolation rate), pore space distribution, particle
size, moisture retention, aggregation, bulk density,
and mineral derivation.

Hydraulic conductivity
Hydraulic conductivity is defined as water flow
through soil in response to a imposed potential gra-
dient. In essence, hydraulic conductivity provides a
measure of how fast water moves through the soil
in relation to the amount of water (rainfall or
irrigation) applied towards a designated drainage
point (tile lines in the case of golf greens). Factors
influencing the hydraulic conductivity of saturated
soils include anything affecting the size and
configuration of soil pores as well as the hydraulic









head placed on the soil surface. Soil texture and
structure are the inherent properties influencing
soil pores. Sand particles, being relatively large
and spherical, cannot "pack" very close together
and result in many macro- (large) pores which
usually drain well. Clay and silt particles, on the
other hand, are very small and/or platelike and can
pack together resulting in numerous micro- (small)
pores. Water cannot pass through micro-pores as
quickly as through macro-pores. Generally, sandy
soils have higher saturated conductivities (drain-
age) than soils high in silt and clay. However,
larger soil pores associated with sandy soils can
become clogged with excessive fine clay and silt.
Therefore, soils with appreciable clay or silt
content (>10% total) should not be used in golf
green construction. Sand from crushed rock are
also available but are often weak and with contin-
ued compaction, break down into fine particles that
reduce drainage rates below acceptable levels.

Hydraulic conductivity is measured in the labo-
ratory by mixing the various ratios of available
sand, soil, and/or organic material being considered
as the root zone mix and placing the sample in a
water bath in order to achieve complete saturation.
The sample is then placed on a tension table or
plate and subjected to 40 cm tension. The rational
of using 40 cm is that this approximates the dis-
tance of the top of the putting surface to the center
of the underlying drain line and the sample is
assumed to achieve field capacity when water is
drained at this tension. Field capacity is the mois-
ture level that many standard soil evaluation pro-
cedures are determined. If more fine particles are
present in the soil sample, the longer it will take for
the sample to reach equilibrium when exposed to
this tension. Once equilibrium is reached, the
sample is compacted with 45 foot-pounds pressure
to simulate typical soil compaction found on greens
at field capacity after several years of use. After
compaction, the sample is then re-saturated and
placed on a percolation apparatus with a 0.25-inch
hydraulic head imposed. The percolate is measured
over time once the flow is stabilized, and the
rate is converted to inches per hour. Hydraulic
conductivity is then determined by Darsy's
equation (Appendix A).

Particle and bulk density
Two important weight measurements of soils
include particle density and bulk density. Particle
density is defined as the mass (or weight) of dry soil
per given unit volume of the soil solids only, not
including pores. Generally, mineral soils (sands,


silts, clays) have higher particle densities compared
to organic matter. Particle density can range con-
siderably but for most mineral soils, this range has
a narrow limit of 2.60 and 2.75 g/cm3 while organic
matter has a particle density of 1.1 to 1.4 g/cm3. An
average figure of 2.65 g/cm3 has been assigned to
indicate the particle density of most mineral
soils and is generally used by soil scientists in
calculating other soil properties.

Bulk density is defined as the mass (or weight) of
dry soil per given unit volume, including both solids
and pores. Bulk density, unlike particle density, is
a characteristic of pore space volume as well as soil
solids. Since most soils are about half solids and
half pore space, bulk densities tend to be about half
of the particle density. Finer-textured soils such as
silt loams, clays, and clay loams, are generally
more compact and have less large pore space thus
higher bulk densities than soils such as sandy soils
which have a high proportion of pore space to sol-
ids. Bulk densities of soils generally range from 1.0
to 1.9 g/cm3. Clay, clay loam, and silt loam soils
normally range from 1.0 to 1.6 g/cm3 while sands
and sandy loams vary between 1.2 and 1.8 g/cm3.
Very compacted soils may have bulk densities of 2.0
g/cm3 or even greater. The ideal bulk density range
for golf greens is between 1.25 to 1.55 g/cm3 with a
minimum limit of 1.20 g/cm3 and a maximum of
1.60 g/cm3.

Soil porosity
Soil porosity or pore space distribution is total
soil volume not occupied by solid particles. In other
words, this is the portion of soil volume occupied by
air and water. In dry soils, pores are filled with air,
whereas in moist soils, they contain both air and
water. The arrangement of solid particles in soil
largely determines pore space. If solid particles lie
close together as in many fine sands or compacted
subsoils, total porosity is low. If they are arranged
in porous aggregates, as often found in medium-
textured soils high in organic matter, pore space
per unit volume will be high. "Ideal" soil porosity of
turfgrass soils contain 50 percent solids and 50
percent pore space, with this pore space equally
divided into 25 percent water and 25 percent air.
Sandy soils generally have a total pore space be-
tween 35 and 50 percent while finer-textured soils
vary from 40 to 60 percent. Golf greens should
have a total of 33 to 50 percent pore space (Table
2). Minimum air-filled porosity which will support
good turfgrass growth is between 10 and 15 per-
cent. Values below these indicate discontinuous
gas diffusion channels.








The amount of smaller pores, called capillary or
micro-pores, will largely determine the soil's water
content, and larger, non-capillary or macro-pores,
will determine the air content. If capillary pores
predominate, moisture holding capacity of the soil
will be high, but water and air movement may be
inhibited due to lack of adequate non-capillary
pores. If non-capillary pores predominate, exces-
sive drainage and aeration result at the expense of
adequate moisture holding capacity. Golf greens
should have a capillary porosity between 20 and 35
percent and non-capillary pore space between 12
and 18 percent (Table 2). These characteristics are
for root zone samples which have been compacted,
allowed to percolate water for 24 hours and then
exposed to a 40 cm tension. Calculating total pore
space involves several tedious steps and these are
outlined in Appendix B.

Particle size analysis
A particle size analysis is important to turf
managers in that it provides a general description
of physical textural soil properties to soil scientists,
and it is the basis for assigning the textural class
name, such as sand, sandy loam, clay, etc., to the
soil sample. Once the analysis is made for the
percent sand, silt, and clay makeup of a sample,
the specific textural class it falls under can be
determined by using the U.S. Department of
Agriculture's textural triangle. This textural
triangle is printed in most introductory soils books.
Soils used for golf greens should fall in the loamy
sand, sandy loam, or loam textural ranges.

Table 2. Recommended porosity of golf green soils by
selective references.
Porosity (cm3/100cm3 or %)
Source Capillary Non-Capillary Total

Anonymous, 1960 15-18 12-18 _33
Benger, 1970 15-21 12-18 >33

Bingaman and --- --- >30
Kohnke, 1970

Anonymous, 1973; 15 --- 40-55
Radko, 1974;
Brewer, 1979
Peterson, 1974 15 --- 50

Gilbert, 1988 20-35 --- 35-55
Anonymous, 1989 --- 15-25 35-50


Golf green root zones mixtures must have a
laboratory analysis to determine the particle size
distribution. Particle size analysis is based on
sieving and sedimentation methods. To make a
particle size analysis, a sample of soil is broken up
and particles larger than silt are separated into
their various sized groups as outlined in Table 1 by
use of sieves and the weight of each group is deter-
mined to give a percentage of total sample weight.
Silt and clay percentages are determined by meth-
ods that depend on the rate of settling of these two
separates from suspension. This principle involves
clay and silt settling rates being roughly propor-
tional to their size (diameter of the particle). There-
fore, the larger the particles (e.g., sand or gravel),
the relatively quicker it will settle in a suspension
(e.g., water) solution. Conversely, the smaller the
particles (e.g., silt and clay), the slower this settling
will occur (this is referred to as Stokes Law). The
equation to calculate velocity of a falling particle
through a suspension is listed in Appendix C.

Another method of separating the particles in
suspension is based on the rate of settling by moni-
toring changes in the specific gravity of the suspen-
sion. A hydrometer is a device that is used to
measure suspension density at various times, thus
reflecting the amount of particles which remain in
suspension after a certain settling time. A hydrom-
eter with a Bouyoucos scale in grams per liter (g/L)
is used to determine the amount of soil in suspen-
sion. The greater the density of a suspension, the
greater the buoyant force on the hydrometer and
the higher the reading. As particles settle out of
the suspension, the density decreases and a lower
reading is obtained. Since temperature influences
the setting rate, a temperature correction must be
made if the suspension temperature differs from
the temperature from which the hydrometer is
calibrated.

Once the proposed sand and soil samples have
had particle size analyses determined, their separa-
tions can be compared to those listed in Table 3.
As Table 3 indicates, there is no one ideal specifi-
cation on the correct particle size distribution that
would be suited for golf greens. Although these
vary considerably, three main points are presented:

1. A maximum amount of 5 percent silt and 3
percent clay (10 percent total) should be al-
lowed or reduced infiltration and percolation
may result.








Table 3. Suggested specifications by various references, for sandy soils used for turfgrass root zones.

Australian Turfgrass University of Penn. State Univ.
United States Golf Association (USGA) Research Institute Minnesota Sand + Soil Sand Only


Textural Name


Clay <0.002

Silt 0.002-0.05


Very fine sand


Fine sand

Medium sand

Coarse sand


Very coarse sand

Gravel


>35 (75 ideal)


I. II.


1.0-2.0

>2.0


}65-85


)<25


}5-10

}<30



}60-70


10-30

<5

0


}>60




<3


--- 60

80 ---
-95


Particle
Size (mm)


i !iI


0.05-0.1


0.1-0.25

0.25-0.5

0.5-1.0


Handreck & Black University ofCalifornia
Acceptable Desirable (sand only)

Particle
T extra l N am e S ize (m m ) ........................................ ...................% ...................................................................

Clay <0.002

Silt 0.002-0.05 }5 to 10 }4 to 8 }0-8

Very fine sand 0.05-0.1

Fine sand 0.1-0.25
}80 to 90
Medium sand 0.25-0.5 }80 to 90 80 to 90 82-100

Coarse sand 0.5-1.0 0 to 15

Very coarse sand 1.0-2.0 0-10
}0-10
Gravel >2.0


................................................................... ...................... % .................................................................................................









2. On the other side of the size spectrum, less
than 7 percent very coarse sand and less
than 3 percent gravel should be present.
These two figures combined should not ex-
ceed 10 percent. If these limits are exceeded
then the following may occur:
a) these large fractions may cut or bruise
the creeping stems stolonss) of the
putting surface grass,
b) these tend to accumulate over time near
the soil surface which results in hard
greens,
c) they dull mower blades when brought to
the surface by core aerification,
d) they make cup-setting and core
aerification difficult, and
e) the soil will not hold adequate water or
nutrients.

3. The principal characteristic of the sand
should be a narrow particle-size distribution
with the majority (>80 percent combined) of
the particles falling in the fine, medium, and
coarse sand (0.1 to 1.0 mm) fractions. Within
this range, the medium-sized particles (with
a diameter of 0.5 to 0.25 mm) should
comprise at least 50 to 70-percent.

Infiltration and percolation rates
Even though they may fall within the particle
size ranges listed in Table 3, it is possible to have
sands that have unacceptable infiltration or water
retention values. Therefore, it is essential that the
chosen sand have a compacted infiltration test
before use. This will help identify any questionable
sands.

Several considerations should be made before
choosing a sand. First, is the infiltration and perco-
lation rate acceptable to the golf club. For most
bermudagrass putting greens, the initial percola-
tion rate should be 10 to 15 inches per hour. Over
time, this initial rate will be reduced by an average
of 1/3 leaving these numbers well above the
minimum of 2 inches per hour required for
bermudagrass. If the club decides on the upper
drainage rate (15 inches per hour), then a sand that
has a major component (minimum 65 percent total)
in the coarse (0.5 mm) and medium sand (0.25 mm)
range should be considered or, alternatively, a
minimum amount of soil or organic matter should
be added to the root zone mix. Ideally, to obtain
this higher drainage rate, 75 percent of the sand
mixture should fall in the medium (0.25 mm) sand


range and as much as possible of the remaining 25
percent should fall in the coarse (0.5 mm) sand
range.

For those clubs desiring a slower infiltration and
percolation rate, then up to 15 of the remaining 25
percent should fall in the fine sand range (0.10
mm). For those desiring still a little slower drain-
ing root zone (therefore, requiring less water and
fertilizer frequency), a minimum of 65 percent of
the sand should fall in the fine to medium sand
categories.

Many times, sands in these rigid categories can
not be found. In these cases, it is suggested that at
least 80 percent of the sample fall in the fine,
medium, and coarse sand fractions. Soils predomi-
nated by larger sizes such as very coarse sand and
gravel, will drain too quickly and have low nutrient
holding capacity. On the other hand, root zone soil
dominated by smaller sizes such as fine sand, very
fine sand, silt and/or clay will become water-logged,
low in soil aeration, and conducive to algae and
moss occurrence. Sometimes a sand washed over a
number 140 or 200 screen will reduce the very fine
sand, silt, and clay to the point of being acceptable.

The addition of well-decomposed organic matter
to the root zone mix helps improve the characteris-
tics of sands that are lacking such as improved
nutrient retention and water holding capacity.
There is a vast array of opinions of the use of soil
amendments for golf greens. A trend in the 1970's
and 1980's was to use pure sand with no additional
amendments added. However, in the 1990's, con-
cerns about pure sand greens and the environment
have many courses reconsidering using some
amendments in this root zone mixture. As
Florida's natural resources become more limited
and pesticide use contingent on root zone percola-
tion and water holding capacity, golf greens in the
south should have some component of organic mat-
ter and/or soil added to help improve their moisture
and nutrient retention capabilities. Without this
added organic matter or soil, greens generally do
not adequately retain water or nutrients. Under
these conditions, the superintendent must apply
water and nutrients more frequently, but, perhaps
at lower rates. Table 4 lists general cation
exchange capacity levels in relation to the soil
textural properties. Table 5 lists several currently
used organic sources for golf green root zone
mixtures while Table 6 lists specific characteristics
of some commonly used peats for modifying root
zone mixtures.









Table 4. Relative cation exchange capacity for different soil
textural properties.
Exchange capacity Level Textural properties
0-6 Very low Sandy soils*

6-12 Low Sandy loams*

12-18 Medium Loams and silt loams

18-24 High Clay loams

>24-200 Very high Clays and certain
organic matter

*Textures used for golf green construction.


One problem with using organic matter as a soil
amendment is being able to evenly distribute it
throughout the root zone soil mix. Pockets of
organic matter often form which diminish its
desirable characteristics. A small amount (e.g., 5
to 10% by volume) of an appropriate soil is usually
easier to evenly distribute compared to some
organic source but care must be used in selecting a
soil source. Many soils are high in clay or silt
(>10% total), which if used, may clog internal water
drainage. Excessive silt and clay is the major
reason river bottom or other sedimentary type soil
or peat are unacceptable for modified soils of high
traffic areas.


Table 5. Qualitative comparison of soil organic amendments used to modify golf green root zones (listed from most to least
desirable).
Cation Exchange Water Holding Durability
Soil Amendment pH Capacity Capacity (years)

Peat humus acid good fair 5+

Reed-sedge peat acid good good 4-5

Moss peat acid fair excellent 1-3

Ground fir bark acid fair fair 5

Lignified wood waste acid poor-fair good 8+

Sawdust acid fair fair 1+

Sphagnum moss peat acid good good 1-3


Table 6. Characteristics of commonly used peals for soil modification.
Level of
Type Composition Color decomposition Remarks

Peat humus non-fibrous dark brown to advanced longest durability
(cultivated peat, black peat) black of peats

Reed-sedge peat semi-fibrous reddish brown partially to none
(lowmoor peat) to dark brown substantially

Moss peat fibrous tan to brown partially difficult to mix
(peat moss, sphagnum peat, into soil
highmoor peat)

Sphagnum moss fluffy, fibrous yellow to tan fresh Used more as a
(top moss) residue of moss surface and for
packing boxes

Sedimentary peat non-fibrous brown to black ----- contains silt and
ash; least
desirable of the
peats; use with
caution








Table 7. Comparison of miscellaneous Inorganic soil amendments used in golf green construction.
Cation Exchange Water Holding Durability
Soil Amendment pH Capacity Capacity (years)

Calcined clay neutral poor fair 10+

Perlite neutral poor fair 10+
Pumice neutral poor low 10+
Vermiculite neutral poor low 10+

Colloidal phosphate neutral good good 10+


Other organic materials have been successfully
used in the root zone component including rice
hulls, and various animal and vegetable by-prod-
ucts. However, availability must be considered
as well as their consistency. When considering
organic sources, make sure to use one that is: (1)
finely shredded to achieve the best possible mixing;
(2) low in silt, clay and salt; (3) well decomposed;
and, (4) free of toxic chemicals.

Other amendments are sometimes used and may
be considered if they are readily available, meet the
infiltration and percolation parameters, and are
affordable. Table 7 lists several of these alternate
soil amendments.

Once a suitable particle size sand is determined,
the laboratory will then run several trial mixes
containing varying proportions of the sand, organic
matter and soil being considered by the golf course.
The synthetically composed samples will then be
compacted and evaluated as previously discussed
for hydraulic conductivity and pore space distribu-
tion. This process is repeated until a ratio that
approaches the optimum standard is found for each
component. Once this is determined, the laboratory
can then make a recommendation to the volume of
each component to be used in the root zone mix.

Root zone mix installation
Procedure
Once the laboratory determination has been
made concerning the type and amount of each
component needed for a desired mix, the next step
is to uniformly mix the components. All root zone
mixing should be completed off-site. Greens
mixed on-site (e.g., soil components placed on top of
each other and roto-tilled in) are poorly distributed,
resulting in localized areas of wet and dry spots.
The use of commercial blending equipment is
strongly suggested to obtain desired results


Figure 9. Commercial mixing of the components of a golf
green root zone "off-site."

(Fig. 9). For smaller jobs, mixing can be preformed
by tumbling in a concrete mixer or by spreading the
measured quantities on a hard, smooth surface
(such as pavement) and then moving by a front-end
loader or tractor in several directions. Once the
mixing operation is underway, random samples
should be obtained and checked by the laboratory
to ensure that specifications are being met. If this
can not be performed, then every truckload of each
component utilized in the root zone mix should be
checked at delivery to insure that specifications are
met as outlined by the laboratory.

During the mixing operation, sand should be
periodically moistened to facilitate more uniform
distribution. Fibrous organic matter should also be
moistened to prevent it from clinging excessively to
wet sand. Incorporating a starter fertilizer and/or
lime, as needed, at this time is also recommended
to aid in early rooting and sod formation. Soil test
results should be used as the basis for determining
amount of fertilizer or lime needed. A complete
fertilizer such as 2.5 to 3 pounds of 10-20-20 or
equivalent should be added to each cubic yard of
mix when soil test results are unavailable.


, :.<-








Once the 4-inch gravel or 2 to 4-inch coarse sand
layer (if it is used) is evenly spaced, 12 to 15 inches
of this laboratory approved root zone mix is placed
on top of it. The desired depth, after settling, is 12
inches. Depending on the organic matter source
used, approximately 20-percent settling of the origi-
nal mix can be expected. Therefore, a 14 to 15-inch
depth will normally settle to approximately 12
inches with several years use.

The root zone mix is transported to the edge of
the green and then unloaded. In order to prevent
disturbances and wheel mark impressions in the
ground by delivery trucks, the soil at the edge of
the green should be dry and firm, otherwise 3/4 or
1-inch plywood should be placed to prevent compac-
tion. This becomes very important when the soil
surrounding the work site is excessively wet or
loose. A small crawler tractor with a blade is then
used for pushing and positioning the root zone mix
out onto the green into a rough grade. The tractor
should always be operated with its weight on the
root zone mix that has been hauled onto the site
and not directly on top of the underlying gravel.
This minimizes the possibility of crushing or dis-
placing the underlying tile and gravel layer. The
grade stakes placed at 10 to 15-foot intervals
should be used as a guide in spreading the root
zone mix and ensuring that the final contours are
developed. Once the initial rough grading is com-
pleted, irrigation installation and soil sterilization
should follow. After the irrigation system is
installed, the entire green should be settled and
firmed by thorough wetting. This wetting will also
check the effectiveness of the drainage system.

Building materials
To estimate costs, the USGA Green Section sug-
gests those quantities of materials required per
1000 square feet of putting surface (Table 8).

Table 8. Materials required to build 1000 sq ft of putting green
surface.
Depth to be Amount of Material
Material Used Required

Gravel 4-inch 12 cubic yards

Coarse sand 2 to 4-inch 6 to 12 cubic yards
Root zone mixture 12 inch 37 cubic yards
Tile --- approximately 100
linear feet


In general, one ton of sand will provide approxi-
mately 20 square feet of 12-inch deep root zone.
When calculating on the amount of root zone mix to
purchase, it is recommended that an additional
2-year supply be purchased for future topdressing
and minor green repairs. If a sand dissimilar to
that originally used for construction is used for
topdressing, the chance of introducing excessive
amounts of very fine sand, silt, and clay is
increased. These fine textured materials could clog
soil drainage pores, resulting in reduced infiltration
and percolation of applied water and eventual
failure of the green.

Irrigation installation
A green normally has an underground, auto-
matic pop-up irrigation system that is installed
near the perimeter of the collar. It is suggested
that one or two quick-coupler hose-end outlets be
installed with this system around each green to
facilitate syringing, watering localized dry spots, or
for other emergency needs. Individual greens
usually require four to six irrigation heads. Having
operational control of each head around the green
is preferred over systems which provide total green
or zone irrigation control. Individual head control
increases irrigation flexibility by allowing for wind
correction, watering localized dry spots, and other
special local needs.

Irrigation heads need to be strategically placed
to minimize the amount of water that is applied
to surrounding bunkers. Constant watering of
bunkers results in sand erosion, wet shots for the
players, algae and weed encroachment (Fig. 10).
Separate irrigation facilities should also be


_9 F-IW


Figure 10. Undesirable golf green bunkers due to a poorly
designed irrigation system which results in
improper irrigation.








provided for slopes and surrounding areas of
greens. Normally, the soil used for these areas are
heavier and poorly drained as compared to the
modified putting greens. Thus, they hold water
better and do not need to be irrigated as frequently
as the well-drained green.

Soil sterilization
Soil sterilization is the next step in producing a
quality playing surface. This provides control of
most undesirable weeds, insects, and nematodes
present in the root zone mix. Maintaining putting
greens with an ever declining number of effective
pesticides, amplifies the need of soil sterilization
before grass establishment. This is especially true
when considering nematode and weed control. The
two most commonly used soil fumigants are methyl
bromide and metam-sodium. Methyl bromide is the
most effective soil sterilization chemical to use.
However, it is highly toxic, requires a polyethylene
cover after application for optimum efficacy (Fig.
11), and a special pesticide license for purchase and
use. Metam-sodium does not require a cover after
application, but is less effective without one and
three weeks are generally required before planting.
It is suggested for those unfamiliar with soil
sterilants contract a custom applicator to perform
this to insure proper and safe application.


Figure 11. Polyethylene cover used to obtain maximum
efficiency from soil fumigation.

Final grading
Once fumigation is completed, the final grade
will probably require a re-check using a level or
transit to ensure that the original specifications are
retained. Any final grading should be done manu-
ally by means of shovels, push boards, and/or drags.
Once the final grade is established, the green is
now ready for firming. Several machines are


available to perform this. A small crawler tractor,
a mechanically powered roller, or a tractor with
wide tires is operated back and forth in numerous
cross angles until the entire surface has been com-
pacted in several directions. The profile can be
enhanced to settle and become firm by irrigating
deeply but not to the point of runoff or else soil
erosion and contour disruption may result. Once a
satisfactory final grade is achieved, the surface
should be smoothed by raking (Fig. 12). Hand
raking is the preferred method but certain types of
mechanical sand rakes are acceptable as long as
the final grade is not significantly disturbed. The
area is now ready to be established (planted) and
maintained.












=- i *^ -
.,o





Figure 12. Hand means using shovels, push boards, and/or
drags are best for final grading and smoothing.

Additional information
Collars
In the planning stages of green construction, it is
suggested that the collar region be constructed
similar to that of the green. Collars receive similar
traffic and maintenance procedures as the green,
and experience has shown that when constructed
similar to greens, problems encountered in main-
taining these regions are minimized. A problem
frequently encountered after green establishment
is excessive drying of soil adjacent to the collar.
This occurs when the adjacent soil is a finer-tex-
ture, therefore, it has a greater tension (affinity) for
the available water in this coarser-textured green
area. Two methods to eliminate this drying
include "ringing" the collar's perimeter with an
impermeable barrier or by gradually grading the
constructed collar's perimeter with a slope of 60 to
80 percent. In the "ringing" process, a strip of
polyethylene sheeting is inserted between the outer
soil and the sandy root zone mix to act as a vertical











A 1
*. .-. q.
*..': r

. .a.
'*i~n~~LL e Ig *~~.


*. D . .1
... .. .. 0


Figure 13. A properly (top) constructed collar with a 60 to 80-percent slope to prevent excessive soil compaction, dry spot
development, and thin turf, and improper (bottom) construction with a thin layer of sand.


barrier, preventing lateral transfer of water into
the adjacent dry soil. This polyethylene ringing
should be placed on the outside perimeter of the
collar's modified root zone mix before the root zone
mix is placed.

The soil mixing method involves mixing and
feathering out from the collar mix with a 60 to
80-percent slope, the putting green top mix (Fig.
13-top). This blending provides an acceptable
transition from the artificial to the adjacent soil
and helps eliminate excessive drying. A vertical
excavation of the green collar edge is not suggested.
The edge should be sloped so that at least one-third
of the green collar is the full depth of the root zone
medium. Care must be taken when using this
mixing procedure as not to contaminate the root
zone mixture on the green with the adjacent soil.
An unacceptable procedure often used is making a
flat sloping collar with a thin layer of sand (Fig
13-bottom). This becomes unacceptable due to the
thin layer of sand being prone to poor percolation,
excessive drying, and soil compaction.


Bunker sand
The ideal particle size range for most bunker
sand is between 0.25 and 1.0 millimeter. Gener-
ally, sand in this range will not remain on top of
the grass after being blasted out of the bunker, but
will seep down into the soil surface. Sand particles
exceeding 1 millimeter tend to remain on the put-
ting surface and interfere with mowing operations
and putting. Sand for bunkers should be light in
color, and round rather than angular, if available.

Summary
Building today's golf green is much more
involved than simply pushing up surrounding soil
and planting grass, the method used to construct
many older greens. The most important step is
determining the components of the root zone mix.
The other steps can be perfectly executed but
unless the proper root zone mix is used, the green's
performance will be less than expected.

Obviously the method of green construction as
outlined in Fig. 3 is the ideal one, but, it is also the








most expensive. Variations of this method have
been used for bermudagrass putting greens in
Florida (Figs. 4 and 5). Clubs have eliminated the
"choker" layer, used gravel sizes outside the desired
range, used synthetic cloth in place of the "choker"
layer, used drain tile only sporadically or not at all,
etc., with varying degrees of success. However, it
must be emphasized that the key for allowing these
variations is the use of an appropriate root zone
mix. At least 12 to 14 inches of the desired soil
mix with tile drainage installed should be
used for green construction. The other compo-
nents (pea gravel, "choker" layer) are used if
finances permit or if a better guarantee of success
is desired. If drainage tile is eliminated, then a
greater subsurface and surface drainage slope and
the 4 inch gravel base are required to make up this
deletion. On the other hand, if the gravel layer is
deleted, drain tile should not be.

No procedure or method of green construction
provides an absolute guarantee of success. Success
depends on the quality of materials used, the qual-
ity of installation and subsequent management.

Selected references and
additional reading
Anonymous. 1960. Specifications for a method of
putting green construction. USGA. Turf Manage.
13(5):24-28.

Anonymous. 1973. Refining the green section
specifications for putting green construction.
USGA Green Section Rec. 11(3):1-8.

Anonymous. 1989. USGA refining the green section
specification for putting green construction. Golf
House. Far Hills, N.J.

Beard, J. B. 1982. Turfgrass management for golf
courses. Burgess Publication Company.
Minneapolis, Minnesota. 642 pp.

Benger, W. H. 1970. Turfgrass soils and their modi-
fication. Proc. 1st. Inter. Turfgrass Res. Conf.
Sports Turf Res. Institute, Yorkshire, England.

Brady, N. C. 1984. The Nature and Properties of
Soils. 9th ed. Macmillan Publ. Comp. NY. 750
pp.

Brewer, W. S., Jr. 1979. When all else fails use
proven guidelines. USGA Green Section Record.
17(1):1-5.


Bingaman, D. E. and H. Kohnke. 1970. Evaluating
sands for athletic turf. Agron. J. 62:464-467.

Davis, W. B., J. L. Paul, and D. Bowman. 1990.
The sand putting green construction and man-
agement. Univ. of California Div. Agric. and
Natural Resources Publication 21448. 22pp.

Gee, G. W. and J. W. Bauder. 1986. Particle-size
analysis. In A. Klute (ed.) Method of soil
analysis, pp. 383-411. Part 1. ASA and SSSA.
Madison, WI.

Gilbert, W. B. 1988. Soil physical properties for golf
greens and athletic fields. NC Turf News.
6(2):20-22.

Handreck, K A. and N. D. Black. 1986. Growing
media for ornamental plants and turf. New
South Wales Univ. Press. Kensington NSW,
Australia. p.124-142.

Hanks, R. J. and G. L. Ashcroft. 1980. Applied soil
physics. Springer-Verlag, NY. 159 pp.

Harper, J. C., II. 1982. Athletic fields: specification
outline, construction, and maintenance. Penn.
State Univ. Agric. Ext. Ser. U. Ed. 82-827. 29 pp.

Radko, A. M. 1974. Refining green section
specifications for putting green construction.
p. 287-297. In E. C. Roberts (ed.) Proc. 2nd Int.
Turfgrass Res. Conf Blacksburg, Va. June 1973.
ASA, Madison, WI.

Peterson, M. 1974. Construction of sports grounds
based on physical soil characteristics.
p. 270-276. In E. C. Roberts (ed.) Proc 2nd Int.
Turfgrass Res. Conf., Blacksburg, VA. June
1973. ASA, Madison, WI.

Taylor, D. H., G. R. Blake, and D. B. White. 1987.
Athletic field construction and maintenance.
Minn. Ext. Ser. AG-BU-3125. 16 pp.

Appendix A
Darsy's Equation for Calculating Hydraulic
Conductivity

K= Q/AT x dL/dH
where:
K = hydraulic conductivity (cm/sec),
Q = quantity of water (cm3) passing through the
soil core,








A = cross sectional area (cm2) of the soil core,
T = time (sec) required for the water to pass
through the core,
dL = length (cm) of the soil core,
dH = head (cm) of the water imposed on the core.

Appendix B
Calculating Soil Porosity
In calculating total pore space or porosity, two
weight measurements of soils, particle density and
bulk density, must be known. By knowing these
two variables, the total solid space makeup of a soil
can be determined. From here, total solid space is
subtracted from 100 to indicate total pore space.

% pore space = 100 [(bulk density of a soil/par-
ticle density of the soil) x 100]

For example, if a sandy soil has a bulk density of
1.50 g/cm3 and a particle density of 2.65 g/cm3, then
the pore (air and water) space will be 43.4%. A silt
loam with 1.30 g/cm3 bulk density and 2.65 g/cm3
particle density possesses 50.9% pore space.

Next is determining what percentage of pore
space is actually filled with water and what portion
is filled with air. In order to determine this, two
additional variables must be calculated. The first
is the water content of the soil by weight. In other
words, this determines the weight of water in a soil
in relation to the total weight of the soil. A sample
of soil is weighed, then completely dried and
reweighed. The numbers are then inserted into
the following equation:

Water content of a soil, by weight = (wet
weight dry weight) / dry weight

Next, the water content of a soil, by volume (of-
ten called the volume metric water content of a soil)
is determined. This is simply found by multiplying
the water content weight by the bulk density of the
soil.

Water content of a soil, by volume = (water
content, by weight) x bulk density

The total porosity (that portion which is filled
with air and that portion filled with water) can now
be calculated. Total porosity, as explained earlier,
can be determined by several methods. Above, this
was found using the equation:

Total soil porosity = 1 (bulk density/particle
density)


The portion of the total soil porosity filled by air
(aeration porosity) is then simply determined by the
following:

Air filled (aeration) porosity = total soil porosity -
the volume metric water content of the soil.

Water filled porosity is then determined by
simply subtracting air filled porosity from the total
soil porosity.

The classical laboratory method of determining
soil porosity involves measuring the water reten-
tion capacity of a saturated sample held at a ten-
sion of 40 cm at 15 atmospheres. Water removed
by this tension is considered to be that which occu-
pies non-capillary pore space and that retained is
considered to occupy capillary pore space for a golf
green. The calculations are as follows:

Percent total porosity =
saturated weight of soil (g) oven dry weight (g) x 100
volume of soil (cm3)
Percent non-capillary porosity =
saturated weight of soil (g) weight with 40 cm tension (g) x 100
volume of soil (cm3)
Percent capillary porosity =
weight with 40 cm tension oven dry weight (g) x 100
volume of soil (cm3)


Field capacity is traditionally determined by sub-
jecting soil cores to a pressure of 1/3 atmospheres
on a pressure plate apparatus. The water released
at this tension is considered to be gravitational wa-
ter (water pulled from a soil by the force of gravity).
The permanent wilting point is determined by
exposing the cores to 15 atmospheres (15 bars) ten-
sion of a pressure membrane extraction apparatus.
Although 1/3 atmosphere and 15 atmospheres are
accepted values for most soils, there is a debate
that sands, by their nature, hold considerably less
water and little available water is left at pressures
greater than 1/3 atmospheres.

By determining the rooting depth of the turf, and
knowing the evapo-transpiration rate, the amount
of water available to the turf may be calculated. A
water retention capacity between 12 and 25 percent
by weight is desirable with an ideal capacity of 18
percent. This translates to the equivalent depth of
water being 0.18 inch held per inch of soil. The
equivalent depth of water is calculated as follows:

Equivalent depth of water = volume metric
water content x the soil depth of the sample.








Appendix C
Stoke's Equation for Calculating the Velocity
of a Falling Particle Through a Suspension
(also referred to as the Pipet Method)

V = g(d' d)D2
18n
where:

V = velocity of falling particle (cm/sec),
d' = density of particle (g/cm3), (2.65 g/cm3 for
most mineral soils),
d = density of medium (g/cm3), (0.997 g/cm3 for
water at 250 C),
g = acceleration of gravity (980 cm/sec2),
D = diameter of particle (cm)
n = absolute viscosity of medium dynee sec/cm2)

In the equation, g,d', and d are constants. If the
temperature is constant, the viscosity of water is
also constant (0.0089 at 250 C, for example). By
substituting these values into one equation, the
following is left:

V=10lxD2 (at250C)


From Stokes equation, it has been calculated
that at 250 C, the settling rate in water of a particle
with the diameter of 0.05 mm (lower limit of sand)
is 0.25 cm/sec, and with a diameter of 0.002 mm
(upper limit of clay) the rate is only 0.0004 cm/sec.
Sand, therefore, has been calculated to settle in a
7.25 inch high cylinder beaker in approximately 74
seconds. If a thoroughly distributed sample is
placed in a 1000 ml cylinder beaker 7.25 inches in
height, it should retain the silt and clay fractions in
suspension longer than 74 seconds, enabling the
soil scientist to separate these from the larger
diameter sand particles. The time required for
settling can also be calculated from the following:

time (sec.) = 18nh where h = height above the
g(d' d)D2 decanting plane (cm).
















































































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