USGA® GREEN SECTION "|

Record

January/February 1999

Volume 37, Number 1 

Aerification:
Barrels and Benefits

A PUBLICATION ON TURFGRASS MANAGEMENT

BY THE UNITED STATES GOLF ASSOCIATION®

1894

JANUARY/FEBRUARY 1999 
Volume 37, Number 1

Cover Photo:
While orange barrels draw contempt 
on our highways, it is conceded that 
progress has a price. In a like manner, 
putting green aerification will cause 
some short-term disruption, but that 
price is worth the long-term benefits.

Record

Orange Barrels and Putting Green Aerification
Progress has a price.
By R. A. (Bob) Brame

Confused About Weather Station ET?
Perhaps You Should Be
ET and crop coefficient data from various 
weather stations are not interchangeable.
By Dr. Paul W Brown

8
Check The View From The Back
Evaluation of a maturing golf course starts from the back tees.
By Darin Bevard

11
For Richer, For Poa
Cultivar development of greens-type Poa annua.
By Dr. David R. Huff

15
Maintain The Best Irrigation Water 
Quality On The Golf Course
Consider the use of a floating intake structure.
By Miles M. (Bud) Smart, Ph.D.

17
News Notes
18
Green Section Educational Program: 
Experience Spoken Here

19
1999 National and Regional Conferences

Even though these trees are low- 
growing, the view to the green of this 
par-3 hole is extremely limited due to 
their presence. See page 8.

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Using the best quality irrigation water is 
good for the golf course and good for 
nature. See page 15.

20
The Seven Dirty Words of Golf Course Maintenance
Watch your language!
By Patrick Gross
22
Turf Twisters

 
 
 
 
Orange Barrels and
Putting Green Aerification

Progress has a price.
by R. A. (BOB) BRAME

WHILE THE SIGHT of orange 

barrels draws contempt on 
our highways, it is conceded 
that progress has a price. In a like 

manner, properly timed putting green 
aerification will cause some short-term 
disruption to play. Putting green aerifi­
cation is one of the most important, 
yet hated and ultimately compromised 
components of golf course mainte­
nance. Aerification is rarely given 
enough credit for being an essential 
component in putting green mainte­
nance. As a result, its purpose often is 
not defined, dates are not locked in 
and guarded, technique and the use of 
the best equipment are often ignored, 
and with this lack of resolve whining 
golfers have their way.

Golf turf management might be said 
to involve four essential/foundational 
agronomic building blocks. They are:

• Fertilization
• Growing Environment 

(sunlight and air movement)

• Mowing

(type of mower being used, bench 
setting, and sharp blades)

• Water Management 

(drainage/aerification plus 
irrigation)

How greens are watered and aerified 
(water management) directly affects 
turf health and playability. This is 
especially true over the intermediate 
(3 to 10 years) and long haul. Limita­
tions in one or more of these essential 
building blocks cannot be countered 
effectively with any conceivable com­
bination of fine-tuning strategies. 
Although the reasons and techniques 
will vary, it is difficult to imagine a 
maintenance program that has been 
successful for any length of time 
(10+ years) that does not include 
aerification.

This article discusses key reasons for 
putting green aerification, considers 
general equipment categories, provides 
some guidelines for developing the 
right program at your course (custom­
izing), and discusses how to minimize 
the disruption aerification causes (eas­
ing the impact of orange barrels). The

Root zone modification programs normally target the top few inches of the soil profile 
with shallow-tine aerification. A key benefit of machines like the Verti-Drain or Soil 
Reliever is fracturing in the lower soil profile.

JANUARY/FEBRUARY 1999

1

focus is bentgrass or bentgrass-Pofl 
annua putting surface maintenance in 
or north of the transition zone.

Key Reasons for Aerifying Greens

There are four primary reasons for 
putting green aerification in routine 
maintenance (interseeding or regrass­
ing would fall more towards renova­
tion). The list includes: (1) soil com­
paction relief (porosity enhancement; 
air, water, and root movement), (2) root 
zone modification, (3) thatch manage­
ment, and (4) surface smoothing.

(1) Root zone compaction caused by 
equipment, cart, and/or player traffic 
will compromise turf health and the 
resulting playability. Compaction re­
duces porosity, which adversely affects 
the free exchange of air, water move­
ment, and root system development.

(2) The accumulation of organic 
matter (thatch) and fine particles (silt 
and/or clay) can, over time, produce 
a surface layer that reduces porosity. 
Aerification can modify the profile, 
improving oxygen, water, and root 
movement, especially when the use of 
hollow tines is combined with core 
removal and backfilling channels with 
high-quality topdressing sand.

(3) Thatch management, while ac­
complished with root zone modifica­
tion, is often needed even if the root 
zone profile does not need to be modi­
fied. A properly built USGA specifica­
tion green is an example of where 
thatch management via aerification 
may be necessary while profile modifi­
cation would not.

(4) The process of punching holes 
and either reincorporating the plugs 
brought up or removing the plugs and 
filling channels can offer some surface 
smoothing. Surface topdressing alone 
will fill/smooth low spots. The combi­
nation of aerifying and the follow-up 
topdressing will, over time, both fill 
low spots and soften high spots, result­
ing in more efficient surface smoothing 
than top dressing alone.

Overview of Equipment Categories

In today’s golf turf industry there is a 
wide variety of aerification equipment 
available. Yet, with more options often 
comes more confusion in determining 
the best equipment to utilize. To sort 
through the equipment available and 
its usage, there are three principal 
categories to consider. These are: (1) 
conventional shallow-tine aerifiers, (2) 
deep-tine aerifiers, and (3) machines 
and/or tines used for summer manage­
ment.

2

USGA GREEN SECTION RECORD

The first category includes a num­
ber of manufacturers with machines 
possessing various options. Basically, 
these aerifiers must be maneuverable, 
capable of producing reasonable tine 
penetration (+/- 3.5"), and offer good 
hole spacing (the most common stan­
dard has been 2" x 2"). Some machines 
offer adjustable hole spacing and/or 
bracket attachments to vary spacing. 
Speed, while often a marketing tool, is 
not as important as quality. The defini­
tion of “quality” is: a machine that 
enters and exits the playing surface 
without causing excessive disruption 
(punches straight into the surface). 
The second category includes aerifiers 
that penetrate much like the first group, 
only deeper. Straight entry of the tine 
into the surface is not as important in 
this category. In fact, certain deep 
aerifiers offer a beneficial kicking or 
fracturing action that is tied to an 
angled entry and/or exit of tines from 
the root zone. Water injection aerifiers 
and deep-drill machines would also fit 
into this category.

The third category, machines and/or 
tines utilized for summer management, 
is most often used to improve oxygen 
and/or water movement. Root zone 
modification, while often a goal of fall 
and spring conventional aerification, is 
not a primary objective with this cate­
gory. The target is to create open chan­
nels in the soil profile with minimal 
putting surface disruption and turf 
trauma. Typically, the equipment used 
overlaps with the first two categories, 
with adjustments made in tines, spac­
ing, and/or speed. While the equipment 
falling into the first two categories is 
normally used with reoccurring repe­
tition, summer opening and venting is 
weather and traffic dependent and may 
not be needed every year.

Customizing

Compaction

The need for aerification for com­
paction relief can develop on soil­
based greens, sand-based greens, and 
everything in between. Although upper 
profile organic matter accumulation 
softens the impact of equipment and 
player traffic, the soil structure below 
eventually becomes compacted. Turf 
quality will then decline through the 
reduction of atmospheric gas move­
ment, water penetration, and root sys­
tem development. To alleviate these 
limitations, it is common to combine 
deep aerification with shallow-tine 
aerification. This is often done with a 

deep-tine aerifier like the Verti-Drain or 
Soil Reliever equipped with solid tines, 
followed immediately with a shallow­
tine aerifier. Using this combination 
of aerifiers relieves compaction in both 
the upper and lower soil profile.

Water injection aerification is also 
used to reduce upper and lower pro­
file compaction. However, the benefits 
have not been the same as conven­
tional aerification and/or deep-tine 
aerification with regard to creating 
open channels in the root zone. This 
is likely because the channels do not 
last as long.

A well-built green will be, to some 
degree, compaction proof for the first 
few years. However, attempting to build 
a USGA green and missing the mark 
with too much silt and clay can result 
in compaction problems equivalent 
to those of poorly constructed and/or 
older soil root zones.

Root Zone Modification

The second issue is root zone modi­
fication. Do your greens have an 
organic matter/thatch accumulation in 
the upper root zone? Is water moving 
into the profile quickly? The goal of 
putting surface management is to keep 
the top few inches of the root zone as 
dry as reasonably possible. Factors like 
root depth, soil type, weather, irrigation 
system, and available staff impact the 
baseline goal of keeping the top few 
inches of the root zone dry. While most 
of a heavy rain will run off, the water 
that goes into the soil profile should 
drain away from the surface as quickly 
as possible. The use of shallow-tine 
aerifiers equipped with hollow tines, 
the removal of plugs, and backfilling 
channels with material of good porosity 
will create the best possible upper pro­
file modification, short of rebuilding.

Root zone modification programs 
normally target the top few inches of 
the soil profile with shallow-tine aerifi­
cation. Occasionally, however, a deep­
drill or deep-tine aerifier with hollow 
tines is used to modify the lower pro­
file. This is time-consuming, expen­
sive, and, if needed on an ongoing 
basis, may indicate the need for green 
reconstruction.

Thatch Management

A program designed to modify the 
profile will also achieve some thatch 
control. A well-built green that has 
been consistently topdressed and aeri­
fied will likely not need upper profile 
modification. However, even a well- 
built green that has not been top-

Completely filled aerification channels achieve the quickest return to smooth putting surfaces (left). Care must be taken to use dry 
topdressing sand so that the channels can be completely filled. If the topdressing contains any moisture, a bridging action will 
occur, and while the holes may appear to be filled, the sand will eventually dry and then drop into the channels (right).

dressed consistently can develop a 
thatch problem. This requires pulling 
plugs, topdressing over them, and 
incorporating the mixture into the 
surface/holes, or completely removing 
plugs and filling channels. Tines only 
need to penetrate deeply enough for 
the thatch accumulation in the upper 
root zone to be removed. It is possible 
to minimize profile disruption and 
equipment tire depressions on the 
surface (often a problem with new 
greens) with short (cut off) coring 
tines. However, the tines do need to be 
long enough and penetrate far enough 
to pull a plug.

Smoothing

Smoothing is the key reason for aeri­
fying a new well-built green, although 
integrating aerification with surface 
topdressing will maintain a homo­
geneous profile. Either topdressing 
over the plugs brought up when aeri­
fying a well-built green and working the 
mixture in, or simply incorporating the 
plugs/root zone back into the surface/ 
holes will offer a smoothing action. 
In smoothing, as with thatch manage­
ment, tines can be shortened to reduce 
profile and surface disruption. Aerifi­
cation offers a smoothing action on 
older and/or poorly constructed greens 
as well, although the smoothing action 
is typically a higher need on new 
greens.

Combination of Needs

In most cases, aerification is done for 
more than one reason. For instance, 
well-built greens are aerified to smooth 
the surface and dilute organic matter 
accumulation if not topdressed regu­
larly. Soil and/or poorly constructed 
high-sand-content greens are often 
aerified to modify the upper profile, 
while also easing compaction and 
smoothing the surface. Deep aerifica­
tion is often added to a maintenance 
program to open, loosen, and/or frac­
ture the lower profile.

Easing the Impact of Orange Barrels

1. Communicate the reasons for 
putting green aerification. At times, it 
seems some golfers think the superin­
tendent lies awake at night pondering 
ways of messing up their round of 
golf. The lack of communication may 
well be the primary reason for this 
mindset. There are times when politics 
may dictate the need for a superinten­
dent to back down and accept the 
golfers’ desires. However, when it 
comes to the four agronomic building 
blocks outlined in the introduction, a 
hard line should be maintained. Even 
though agronomics, economics, and 
politics are part of every maintenance 
decision, it is the agronomics that pro­
tects the intermediate and long-term 
performance and conditioning of the 

course. Make sure golfers understand 
why aerification is more important 
than, for example, edging bunkers or 
mowing around trees. Through news­
letter articles, superintendents should 
explain why it is important to move 
water away from the surface as quickly 
as possible. Firm, dry surfaces equate to 
healthier turf and better playability — 
benefits that few golfers could argue 
with. Golfers would better understand 
the necessity of aerification if a hier­
archy of goals were made known. For 
instance: (1) shallow-tine aerification 
targets upper profile modification, (2) 
deep aerification punches through 
the compaction zone at the bottom of 
shallow-tine penetration and enhances 
lower profile porosity, and (3) solid star 
tines and water injection are used in 
the summer to maintain positive atmo­
spheric gas and water movement. 
Deep, plump, white roots growing 
down aerification channels dramati­
cally communicate what “enhancing 
profile porosity” actually means.

A physical analysis of the soil pro­
file by an accredited laboratory can 
scientifically quantify aerification re­
quirements. This may help golfers 
understand why the greens are being 
shallow-tine aerified three or four times 
a year and deep aerified twice. The 
laboratory analysis may expose the 
fact that an aggressive aerification pro­
gram is postponing the need to rebuild.

JANUARY/FEBRUARY 1999

3

It is important for golfers, at least 
those who are interested, to understand 
all sides of the issue. That’s what com­
munication is all about. Don’t assume 
anything.

2. Equipment selection. Golferswill 
be more tolerant and understanding of 
aerification work if surface disruption 
is held to a minimum. This means the 
greens must putt reasonably smoothly 
the day after aerification. To achieve 
this goal, use a quality machine and 
completely fill the holes produced by 
aerification.

A quality shallow-tine aerifier 
punches straight into the putting 
surface. If the tines enter at even a 
slight angle, the holes will be oblong. 
The raised or slight mounding behind 
the holes creates surface disruption 
that takes time to smooth. Even rolling 
the surface after using a poor-quality 
machine will not completely eliminate 
ball roll disruption. The sacrifice in 
speed to punch crisp round holes is 
worth the investment.

Completely filling aerification chan­
nels and using a quality machine will 
achieve the quickest possible return to 
smooth putting surfaces. The only way 
aerification holes can be completely 
filled is with the use of dry topdress­
ing sand. If the topdressing contains 
too much moisture, a bridging action 
occurs and, while the holes may appear 
to be filled, the sand will eventually dry 
and then drop into the channels. The 
result is inefficient upper profile modi­
fication and partially open holes, pro­
ducing bumpy putting surfaces. This 
also applies to a well-built green where 
upper profile modification is not a 
goal. It is for this reason that either 
topdressing (using the sand component 
of the construction mix that is com­
pletely dry) over plugs and incorpo­
rating the mixture into the surface/ 
holes, or completely removing plugs 
and filling channels, is preferred to 
simply working in the plugs alone.

A key benefit of machines like the 
Verti-Drain or Soil Reliever is the 
fracturing that occurs in the lower 
profile. The kicking action generated 
by these machines usually results in 
some minor surface disruption. While 
the kicking action can be adjusted, 
some action is needed to provide the 
desired fracturing action. The soil 
moisture level is also important in 
achieving the desired fracturing. Too 
much root zone moisture virtually 
eliminates fracturing, while too little 
may result in significant surface dam­
age. Following deep-tine aerification 

4

USGA GREEN SECTION RECORD

with a quality shallow-tine aerifier can 
aid in smoothing the surface, while 
blurring the holes from deep opening. 
This makes it possible to stay with the 
typical combination of removing shal­
low-tine aerification plugs and back­
filling channels. Using both machines 
holds play disruption to one time 
frame, while receiving the combination 
of benefits.

Once the reasons for aerifying greens 
have been established, make sure the 
equipment complements the goals. 
While water injection aerifiers can be 
a tool, they allow neither profile modi­
fication nor the smoothing action pos­
sible when plugs are pulled. This is 
actually true of virtually all machines 
and/or tine combinations used for 
summer opening and venting. There is 
a tendency at some courses to move 
toward less disruptive and/or quicker 
aerification strategies at the expense of 
doing what is really needed for turf 
health.

3. Schedule properly and stay the 
course. Summer aeration, to open and 
vent the profile, is difficult or impos­
sible to pre-schedule. The need will 
vary with weather conditions, traffic, 
and turf health. Some flexibility, like 
the course being closed for one-half 
day on Monday, should be factored in 
to allow this work some latitude. Con­
ventional and deep aerification can 
and should be scheduled in advance.

The best approach is to take the 
course calendar and enter all aerifica­
tion dates before golfing events are 
added. Ideally, place an alternate date 
two or three weeks after each target 
date. This ensures aerification will be 
done, even if a temporary postpone­
ment is necessary. Weather conditions 
and/or weak turf/roots may force a 
temporary postponement — golfing 
events should not. With target and 
alternate dates on the course calendar, 
golfing events can be added where 
appropriate. Advance scheduling pro­
tects aerification, while allowing golfers 
to be informed. The ongoing aerifica­
tion of greens is more important than 
any one golfing event.

When greens are being aerified, 
either close the entire course, nine 
holes, or the applicable hole(s). The 
best policy is to either close nine holes 
at a time or close the entire course. The 
safety and efficiency of putting green 
aerification will be much better if play 
is not allowed during the process.

While the actual timing of the target 
dates will vary depending upon loca­
tion, the late summer/early fall time slot 

is ideal. The more aggressive fall fertili­
zation combines with the enhanced 
root zone porosity offered by aerifica­
tion to strengthen root depth and 
mass. Mid-fall or mid-spring would be 
slot number two. Three conventional 
aerifications a year would normally tar­
get late summer/early fall, mid-fall, and 
mid-spring. Should four be needed, add 
late spring to the schedule. Deep aerifi­
cation can be inserted just before any 
one or combination of the shallow-tine 
openings.

To achieve the quickest possible 
grow-over, all aerification work should 
be done when the turf is actively 
growing. Aerifying in late fall or early 
spring can expose the turf to more 
intense winter desiccation or overly 
wet root zones (open channels, even 
if completely filled as is the target, will 
allow more of a heavy rain to pass into 
the profile).

Once scheduling is completed, stay 
the course. Consistency is important to 
achieving maximum value.

Conclusion

Ultimately, the first step toward 
properly aerifying greens is to acknowl­
edge its importance. The use of high 
quality, properly selected equipment 
can combine with ongoing communi­
cation and advance scheduling to 
minimize the presence of orange bar­
rels. Yet, with progress comes orange 
barrels.

References

Callahan, Lloyd M. (1998). Thatch control 
in bentgrass greens. Turfgrass Trends. 
Volume 7, Issue 9, September 1998, pp. 1-9.

Mascaro, Tom (1988). Greens Aerification. 
Golf Course Management. Volume 56, No. 
7, July 1988, pp. 16-20.

Murphy, J. A., Rieke, P. E., & Erickson, A. 
E. (1993). Core Cultivation of a Putting 
Green with Hollow and Solid Tines. 
Agronomy Journal. Volume 85, No. 1, 
January/February 1993, pp. 1-9.

Watson, James R. (1990). Choosing Appro­
priate Aerification Methods for Greens. 
Golden State Fairways — Second Quarter 
1990. Volume 2, No. 2, May 1990, pp. 32- 
35.

BOB BRAME joined the Green Section 
staff in early 1990. Following a few years 
in the Mid-Atlantic Region, Bob opened 
an office in Covington, Kentucky, where 
he now serves as Director of the North 
Central Region. Bob visits courses in 
Indiana, Kentucky, and Ohio.

Confused About Weather Station ET? 
Perhaps You Should Be

ET and crop coefficient data from various weather stations are not interchangeable.

by DR. PAUL W. BROWN

USE OF evapotranspiration (ET) 

data has been touted as the 
means by which golf course 
superintendents can refine and opti­

mize irrigation management. Today, 
most superintendents in the Desert 
Southwest can access local ET data 
from a public weather network or their 
own on-site weather station. In many 
cases, ET from on-site weather stations 
is integrated into sophisticated com­
puter software that directly controls 
daily course irrigation schedules. While 
the use of ET data often leads to im­
proved irrigation management, better 
turf quality, and lower operating costs, 
widespread proliferation and use of 
ET derived from weather stations does 
pose some problems that need to be 
addressed to make this data more 
reliable and useful to superintendents. 
The focus of this article will be on an 
important but rarely discussed prob­
lem: the procedure used by the weather 
station or its attendant software to 
compute ET. We begin with an explora­
tion of the problem, then summarize 
results of a recently completed study 

designed to provide solutions to the 
problem.

Misconceptions About ET

A common misconception among 
many in the turf industry is that a 
weather station actually measures turf 
ET. This is not the case. Weather sta­
tions monitor meteorological variables 
that impact turf ET, including solar 
radiation, wind speed, humidity, and 
temperature. The resulting weather 
data are then input into meteorological 
models that estimate reference evapo­
transpiration, which is commonly 
abbreviated ETo. ETo is defined as the 
water lost from a well-irrigated, tall (3- 
6"), cool-season grass (ryegrass or 
fescue) by the combined processes of 
transpiration and soil evaporation. 
Factors ranging from turf species to 
mowing height cause the ET from golf 
turf to differ from that of ETo. For 
example, a bermudagrass fairway turf 
maintained at a height of W' would 
likely use less water than the much 
taller cool-season reference grass that 
supports a higher leaf area and interacts 

Weighing lysimeters are accurate to within 0.01" per day in measuring actual water 
use of the turf grass (ETa) maintained under fairway management conditions.

more readily with wind. We commonly 
employ a simple multiplicative adjust­
ment factor known as the crop co­
efficient (Kc) to adjust or convert ETo 
to actual turf ET (ETa):

ETa = Kc x ETo (Equation 1)

The key to optimizing the use of 
weather stations on a golf course is 
the selection of appropriate crop co­
efficients. Crop coefficients often differ 
for tees, greens, fairways, and roughs; 
therefore, availability of the appropriate 
Kc is required to tailor irrigation for 
each type of turf. Crop coefficients are 
usually developed in controlled re­
search studies where actual turf water 
use (ETa) is compared with values of 
ETo computed from meteorological 
parameters. Rearrangement of Equa­
tion 1 provides the mathematical basis 
for developing Kes, and reveals that 
Kes are dependent on both the mea­
sured value of turf water use (ETa) and 
the computed value of ETo:

KC = ETa/ETo (Equation 2)

It is at this point where the problems 
and confusion develop with use of ETo 
derived from weather stations. The 
procedure for computing ETo is not 
standardized. While there are two 
general models used to estimate ETo — 
the modified Penman Equation and 
the Penman-Montieth Equation — the 
scientific community has developed 
and recommended numerous modifi­
cations to each general model to pro­
vide better fits to local data sets or 
local environmental conditions. Unfor­
tunately, this scientific refinement has 
led to the publication of numerous 
procedures for estimating ETo, many 
of which generate different values of 
ETo when supplied with the same 
meteorological data.

The ETo computation problem is 
depicted in Figure 1, where data from 
a single meteorological station were 
used to compute ETo using modified 
Penman Equations employed by the 
public weather networks in Arizona 
(2), California (5), and New Mexico (4). 
Our experience with the ETo proce­
dures provided by private vendors of 

JANUARY/FEBRUARY 1999

5

weather stations and irrigation man­
agement software suggests ETo compu­
tation also is a problem with weather 
stations provided by the private sector.

ET Computation

While the ETo computational prob­
lem may seem trivial or academic to 
some, the problem does generate nega­
tive consequences on at least two 
fronts. The most imporant conse­
quence is practical in nature and relates 
to our ability to effectively transfer and 
use Kes developed in regional research 
studies. Suppose, for example, that on

Reference evapotranspiration (ETo) for 
19 June 1996 at Tucson, Arizona, com­
puted using the modified Penman Equa­
tions used by CIMIS (CA), AZMET 
(AZ), and New Mexico Climate Center 
(NM).

Bermudagrass crop coefficients (Kes) 
developed for 19 June 1996 at Tucson, 
Arizona, using lysimeter measurements 
of actual water use and ETo values com­
puted using the modified Penman Equa­
tions used by CIMIS (CA), AZMET 
(AZ), and New Mexico Climate Center 
(NM).

6

USGA GREEN SECTION RECORD

the day depicted in Figure 1, Arizona 
researchers also measured an actual 
turf water use (ETa) of 0.30". From 
Equation 2, the crop coefficient appro­
priate for the Arizona procedure would 
be 0.30'70.40" or 0.75. However, if a 
golf course in New Mexico takes the Kc 
of 0.75 and applies it to the ETo avail­
able from the New Mexico Climate 
Center, one would seriously overesti­
mate fairway water use. The appropri­
ate Kc for New Mexico needs to take 
into account their ETo procedure and 
thus would be 0.30'70.46" or 0.65.

The bottom line on Kes: they must be 
paired with the ETo procedure utilized 
during their development. We feel that 
much of the bad press given to Kes 
results from the failure to recognize 
the need to adjust/modify Kes for the 
method of ETo computation.

A second negative consequence of 
differing procedures for estimating 
ETo rests in the realm of regulation. 
Governmental agencies charged with 
regulating water use are beginning to 
use ETo as a means of assessing and 
regulating water use and allocation, 
especially in water-short regions such 
as the Desert Southwest. If in the 
future water allocations to golf courses 
are set based on ETo and Kes, then it 
will be in everyone’s interest that the 
problems and procedures required to 
deal with the ETo computation prob­
lem be resolved in a sound, scientific 
manner. Failure to do so will produce 
additional and unnecessary legal and 
political wrangling over the issue of 
golf course water requirements.

Solutions on the Horizon

At this point we have only addressed 
the problem of ETo computation, not 
the solutions. Fortunately, solutions to 
the problem are beginning to emerge. 
An obvious solution would be to de­
velop a standard procedure for com­
puting ETo. The scientific community 
is presently moving forward with such 
a proposal that would utilize a standard 
form of the Penman-Montieth Equa­
tion to estimate ETo (1). Development 
of a standard procedure should mini­
mize future problems with ETo com­
putation, provided both the scientific 
community and the commercial sup­
pliers of weather stations and irrigation 
management software accept the pro­
cedure. However, in the interim, we 
need some means of interpreting and 
normalizing the numerous ETo proce­
dures in existence at this time so 
superintendents and the regulatory

On-site weather stations are often 
integrated with computer software that 
can automatically adjust operating 
times of irrigation sprinklers.

community can make better use of 
ETo data.

A research study presently underway 
at the University of Arizona Karsten 
Desert Turf Facility is focused on pro­
viding this needed interim assistance to 
golf courses that utilize ETo data from 
public or private weather stations. Two 
large weighing lysimeters, each planted 
to Tifway bermudagrass and main­
tained in accordance with fairway 
standards, provide daily values of ETa. 

The lysimeters are overseeded in 
October with an intermediate ryegrass 
that serves as the winter turf surface. 
Automated weather stations are located 
adjacent to the lysimeter facility and 
provide the necessary meteorological 
data for computation of ETo.

Appropriate crop coefficients have 
been developed for ETo procedures 
used by the California Irrigation Man­
agement Information System (CIMIS) 
(5), the Arizona Meteorological Net­
work (AZMET) (2), the New Mexico 
Climate Center (4), and the ET 
Feedback System used in Las Vegas (3) 
during the early 1990s. A fifth proce­
dure for computing ETo, a version of 
the Penman-Montieth Equation 
recommended as an international 
standard, also is included in the study. 
Results from this study clearly drive 
home the point that crop coefficients 
must be matched to the ETo compu­
tation procedure.

Figure 3 presents the appropriate 
seasonal crop coefficients for bermuda­
grass fairways during the summer 
months of May through September 
for each of the five aforementioned 
methods of computing ETo. It is im­
portant to remember that the turf 
water use data used to compute the Kc 
and the weather data used to compute 
ETo are the same for all five methods 
presented in Figure 3. The variation in 
seasonal Kc is totally a function of the 
procedure used to compute ETo.

Figure 4 presents a similar picture for 
winter Kes when the bermudagrass is 
overseeded with ryegrass. The data in 
Figures 3 and 4 show the danger of 
using a Kc provided by another scien­
tist or superintendent without first 
identifying the ETo procedure that 
was used to produce the Kes. In the 
extreme case presented in Figure 3, if 
a Kc appropriate for New Mexico’s ETo 
were used in California with CIMIS 
ETo, we should expect significant 
under-irrigation to result. In contrast, 
if one applies the Kc appropriate for 
California to ETo in New Mexico, one 
would likely over-irrigate the turf by 
nearly 30%.

The Arizona study also is working 
to find a solution for superintendents 
who operate their own weather sta­
tions. The large number of commercial 
suppliers of weather stations/irrigation 
management software and a reluctance 
on the part of some suppliers to release 
trade secrets precluded us from directly 
developing Kc values and correction 
factors for commercial equipment. In­
stead, we chose to develop a data set

Figure 4

(Z)

2 0.9
OX)

Seasonal bermudagrass crop coefficients 
(Kes) developed for five regional proce­
dures used to estimate ETo. CA: Cali­
fornia (CIMIS), NM: New Mexico, NV: 
Nevada (ET Feedback), AZ: Arizona 
(AZMET), PM: Penman-Montieth.

that contains both weather data and 
actual values of turf ET. This data set 
is presently being finalized for publi­
cation and release via the University 
of Arizona and the USGA. The availa­
bility of such a data set allows the 
manufacturers of weather stations and/ 
or irrigation management software to 
1) compare their ETo computations 
with those procedures evaluated in 
the Arizona study, and 2) develop Kc 
values for a common fairway turf 
system in the Desert Southwest. We 
anticipate that many of the commercial 
suppliers of weather stations and irri­
gation management software will 
utilize this data set to provide Kes and 
ETo translation factors for existing 
owners of their products.

The concept of basing irrigations 
on ETo values derived from automatic 
weather stations is a proven tech­
nology. The problems associated with 
computation of ETo add to the diffi­
culty of using and improving ET-based 
irrigation management systems; how­
ever, future efforts to standardize the 
computation of ETo should help elimi­
nate this problem in the future. We 
encourage the turf industry to seriously 
consider adopting a standard ETo 
procedure to facilitate effective use of 
regional research on turf water man­
agement and to minimize potential 
problems with the regulatory com­
munity. We also suggest that future 
studies aimed at developing Kes collect 
and provide access to meteorological 
data required for computation of ETo 
so public weather networks and com­
mercial suppliers of irrigation manage­
ment equipment can develop Kes

CA NM NV AZ PM

Seasonal crop coefficients (Kes) for over­
seeded ryegrass developed for five 
regional procedures used to estimate 
ETo. CA: California (CIMIS), NM: New 
Mexico, NV: Nevada (ET Feedback), 
AZ: Arizona (AZMET), PM: Penman- 
Montieth.

appropriate for their procedures of 
computing ETo. Simply using the 
Arizona data set will not provide Kes 
appropriate for many temperate or 
humid regions, and using arid region 
climate data to compare ETo methods 
in humid regions may not provide 
legitimate translation factors.

References
Allen, R. G., M. Smith, L. S. Pereira, and 
A. Perrier. 1994. An update on the calcula­
tion of reference evapotranspiration. ICID 
Bulletin 43(2) :35-92.
Brown, P. W. 1998. AZMET computation of 
reference crop evapotranspiration. AZMET 
Web Page: http://ag.arizona.edu/asmet.html. 
Devitt, D. A., R. L. Morris, and D. C. Bow­
man. 1992. Evapotranspiration, crop coeffi­
cients, and leaching fractions of irrigated 
desert turfgrass systems. Agron. J. 84:717-723. 
Sammis, T. 1996. Penman’s Equation refer­
enced to grass. New Mexico Climate Center 
Website: http://weather.nmsu.edu/math/ 
penmans.html. New Mexico St. Univ.
Snyder, R., and W. Pruitt. 1985. Estimating 
reference evapotranspiration with hourly 
data. California Irrigation Management In­
formation System Final Report. R. Snyder et 
al. (eds.). Land, Air, and Water Resources 
Papers 10013-A, Univ, of California-Davis. 
Chpt. VII: 1-3.

DR. PAUL BROWN is the Extension Bio­
meteorologist at the University of Arizona. 
He oversees the operation of the Arizona 
Meteorological Network (AZMET), a 
public weather network that supplies 
weather information to turf managers and 
agricultural producers located in southern 
Arizona. He has been actively involved in 
efforts to assess the water requirements of 
desert turfgrasses for the past five years.

JANUARY/FEBRUARY 1999

7

Play on this hole is compromised because of the tree on the left. Even from the back right portion of this tee, a large portion of the 
green is blocked. The bunker on the left is obscured, and the usable teeing area is reduced.

CHECK THE VIEW 
FROM THE BACK

Evaluation of a maturing golf course starts from the back tees.

by DARIN BEVARD

THE GOLFER steps up to the 

tee for his drive. He remembers 
years ago when a long, right-to- 
left shot would leave him a perfect 

approach to the green from the right 
center of the fairway. Now he must 
hit a short lay-up shot to avoid hitting 
the ball into the hazard on the left 
side of the landing area. “It was never 
meant to play this way,” he thinks. 
What has happened?

At the time of construction, many 
golf courses have very few trees in their 
landscape. Often, trees are planted as 
an afterthought to make the course 
more difficult, more visually appealing, 
or to provide safety buffers and visual 
separation between adjacent holes. 
However, as the trees mature, the in­
tended lines of play from tee to fair­
way and fairway to green can change 

8

USGA GREEN SECTION RECORD

greatly. Features such as bunkers and 
water hazards may also become less 
visible to the player, especially from 
the tee. It basically comes down to 
the effects of these additions on the 
original design or presentation of the 
hole, especially as viewed from the tee.
Oftentimes the golf course superin­
tendent is the one person who provides 
continuity to the course maintenance 
and improvement program and can 
observe how the golf course changes as 
it evolves and matures. Green Com­
mittees change. The turf manager has 
the opportunity to monitor changes in 
golf holes over time by evaluating the 
golf course on an annual or semi­
annual basis. One way to perform this 
evaluation is from the back tees of 
each hole, keeping the other tees in 
mind as well. This allows the hole to 
be evaluated from tee to fairway from 
much the same perspective as the golfer 

experiences it. In fact, it may even be 
beneficial to take pictures of each hole 
from the back tees to keep a record of 
how the course changes from year to 
year.

There are several different issues that 
can be evaluated during this process. 
These include alignment of tees, effects 
of trees and underbrush on visibility of 
hazards, effects on direction of play, 
and how this vegetation affects wear 
distribution on tees. There are other 
agronomic factors to consider as well. 
If these factors are evaluated on a 
regular basis, playability and fairness 
can be maintained without having to 
implement drastic changes. Oftentimes 
smaller trees can be moved to better 
locations where their impact on play 
is minimized, eliminating the need for 
the tough, emotional decisions that 
need to be made when a mature tree is 
involved.

Tee Alignment

This article will not address the 
issues of free-form, purposely un­
aligned tees vs. square-cornered tees. 
Rather, for this article it is assumed that 
the course wants tees aligned to the 
direction of play.

Through the planting of trees or 
through poor mowing practices, proper 
alignment between tees and fairways 
can be lost. Over time, a tee that once 
aimed to the centerline of the fairway 
may now be aligned off to one side of 
the golf hole. It has been my experience 
that if a tee is angled to the right, so is 
the golfer. If that golfer slices, as most 
do, the shot ends up in the rough or in 
the trees. This can add strokes, slow 
play, and frustrate the golfer.

One way to address this problem, 
in the worst case, is to rebuild and 
properly realign the tee, keeping in 
mind the changes that have occurred. 
However, another solution may be to 
simply alter mowing patterns. This is 
an inexpensive solution, but adds to 
the appearance and playability of the 
hole. By reshaping the mowed area of 
the tee to align in the proper direction, 
the player perceives the tee as being 
properly aligned even though the actual 
tee may not be. This can aid the player 
in preparing to play a shot more than 
most would suspect.

Hazard Issues

Another aspect that should be care­
fully evaluated from the tees is the effect 
maturing trees have on visibility and 
playability of hazards. Hazards can 
become obscured from view, and the 
player has no way of knowing a hazard 
is present except for local knowledge. 
The integrity of important features can 
be lost. Hazards, once positioned to 
challenge and even define a golf hole, 
can be hidden or lost. A lack of visi­
bility can also present Rules of Golf 
problems. Questions some up, such as 
“Where did the ball last cross the 
margin of a water hazard? Did the ball, 
in fact, enter the hazard?” It is not 
imperative that the player sees the 
entire hazard. However, if the hazard is 
more visible, it can allow effects on 
playability to be known.

Planting trees can take hazards out 
of play altogether. Generally, where no 
trees were called for during the original 
construction, and a hazard is present, 
the architect intended for the hazard to 
provide the obstacle for the player. By 
planting trees, the trees can become 
the obstacle, and the hazard no longer 

is needed or, worse yet, creates a double 
hazard situation and the player is 
forced to negotiate both the trees and 
hazard.

The other problem with blocking 
the view of bunkers as well as water 
hazards is that the aesthetic value of 
the hole is often decreased. The con­
trast between the sand or water and 
the grass is no longer present.

Unfortunately, when these situations 
occur, there are no simple solutions. It 

is often a question of maintaining the 
hazard or removing the trees or vice 
versa. It makes little sense to continu­
ally provide maintenance for a bunker 
that rarely, if ever, comes into play, 
unless it defines direction.

Direction of Play

As they continue to mature, trees or 
other added obstacles can force a 
change in the direction of play for a 

The left portion of this tee is virtually unusable due to the presence of the trees 
on the left. Wear is concentrated on the right side of the tee while the left side 
receives little traffic.

JANUARY/FEBRUARY 1999

9

golf hole. For example, when trees are 
first planted, a shot can be played over 
them. As they grow, they force play to 
go around them. This forces the player 
to hit a lay-up shot or to manufacture 
a shot to avoid hitting into a bunker 
or water hazard that at one time was 
never even in the line of play for a 
properly played shot. Worse yet, these 
types of plantings can force play in 
the direction of adjacent holes, pre­
senting a safety hazard for other 
players. Efforts should also be made 
to prevent weed trees growing in waste 
areas from becoming large enough to 
affect direction of play or the view of 
the hole.

Agronomic Considerations

The effects of maturing trees on the 
playability of a golf hole from tee to 
fairway are often obvious. However, 
the effects on wear distribution on the 
actual tee are often not noticed by the
layperson.

Placing an obstacle of any kind in 
the line of play between tee and fairway 
will generally cause the player to select 
one side of the tee or the other. For 
example, if a tree blocks the line of sight 
to the left side of the hole, shots will 
generally be played from the right side 
of the tee box in an effort to avoid 
interference. This often leads to one 
side of the tee exhibiting poor turf 
quality due to high amounts of divots 
being taken in a very small portion of 
the tee. Usable teeing space can be

This tree provides a double hazard situation. The location forces the player 
to hit out of the bunker and negotiate the tree as well. One or the other should 
be considered for removal.

greatly reduced when trees encroach 
on the line of sight from tee to fairway.
One other agronomic factor that 
should be examined on championship 
tees is not related to trees at all. Thatch 
accumulations on back tees are often 
extreme. This can be a result of these 
tees being ignored to some degree from 
a maintenance standpoint. However, 
thatch accumulations generally result 
from the lack of traffic these tees 
receive. It’s ironic that thatch accumu­
lations are usually the worst on the 

back tees. The golfers who play from 
these areas are the ones who find the 
spongy surface most objectionable and 
can actually tell the difference while 
playing the game. Evaluating this 
aspect of the championship tees can 
also be important.

Summary

Evaluating your golf course on a 
regular basis and correcting small 
problems as they occur can prevent 
major changes from occurring with 
regard to tree encroachment and other 
factors. The architectural integrity of 
individual golf holes and their associ­
ated hazards can also be protected. 
Trees or other obstructions can add to 
the character of a golf hole when they 
are properly placed. Remember that 
trees grow, and as they do, they can 
have a profound effect on the golf 
course.

As a suggestion, take some time and 
evaluate the appearance and playability 
of individual golf holes from the back 
tees, and don’t forget the more forward 
tees. As a turf manager, it is easy to be 
consumed by agronomics and forget 
what the golf course is really for. To 
the golfer, it’s how the hole looks and 
plays!

DARIN S. BEVARD is an agronomist in 
the Mid-Atlantic Region. He has been 
with the Green Section since 1996, visit­
ing golf courses in Delaware, Maryland, 
Pennsylvania, Virginia, and West Virginia.

A slight altering of the mowing pattern on the tee can provide much better alignment 
to the fairway and eliminate the need for costly renovations.

10 USGA GREEN SECTION RECORD

FOR RICHER, FOR POA

Cultivar development of greens-type Poa annua.

by DR. DAVID R. HUFF

FOR RICHER, for poorer. In 

sickness and health ...These 
simple words underscore one of 
life’s greatest commitments. It also de­

scribes the golf course superintendent’s 
daily commitment to maintaining golf 
greens that are comprised of Poa 
annua.

Poa annua has been part of the golf 
industry for a long time, probably ever 
since the inception of the game. Some­
time around the early 1900s, bentgrass 
became the chosen or preferred grass to 
grow and maintain on golf course putt­
ing greens. Yet, Poa annua continues 
to be a major component, and in many 
cases a dominant component of golf 
course putting greens.

By virtue of its prolific seed head 
production, occurring under even the 
closest of mowing heights, Poa annua 
has been able to evolve a competitive 
edge against creeping bentgrass in 
terms of shoot density, verdure bio­
mass, and photosynthetic surface area. 
Moreover, under shady, moist, cool 
temperature conditions, Poa annua 
thrives and continues to gain a com­
petitive edge against bentgrass until it 
ultimately dominates many golf green 
putting surfaces.

Observations such as these have 
played a key role in initiating Penn 
State’s breeding program for develop­
ing commercial sources of Poa annua 
for use on golf greens. Yet some people 
view this idea as ridiculous; Poa annua 
is, after all, the enemy, isn’t it? Never­
theless, an underlying truth is undeni­
able: superintendents who have Poa 
annua greens simply do not have a 
hope of obtaining a seed source for the 
types of Poa annua that are adapted 
to their golf green environments for use 
in routine overseeding, repair work, or 
new green construction. This industry 
need is the motivation and spirit that 
drives our breeding program towards 
what we hope will produce commer­
cially available seed sources of greens- 
type Poa annua. Only time will tell if 
we will be successful.

Natural Selection

Nature, coupled with the intense 
selection pressure provided by super-

Genetic diversity abounds in the multiple selections of Poa annua. One goal of the 
Penn State University breeding program is to provide golf course superintendents 
with a commercially available seed source of greens-type Poa annua

intendents and golfers, has performed 
a tremendous amount of evolutionary 
change in Poa annua during the past 
100 years — from the wild and weedy 
annual bluegrasses that first invade a 
green, to the highly specialized, high- 
quality, greens-type Poa annua that we 
can find today. Our breeding program 
utilizes this natural evolutionary 
process by collecting and screening its 
products. We regularly collect samples 
from old, closely mowed greens from 
several regions of the U.S. and Canada.
Due to the reproductive biology of 
annual bluegrass, we believe this is a 
fruitful approach. Poa annua has a 
self-pollinating type of breeding system 
that results in true breeding strains 
through inbreeding. Eggs within the 
flowers (florets) are often fertilized be­
fore the florets ever open (cleistogamy). 
Such an inbreeding system of sexual 
reproduction is unique among the 
grasses we typically use for turf, and is 
most similar to that of wheat or soy­
beans. Poa annua also is a polyploid 
grass species, meaning that each of its 
cells carries multiple copies of its 
ancestors’ chromosomes. Polyploidy 

is rare among animals and insects, 
but is common among plants. Among 
grasses, polyploidy is often the normal 
state of being.

Poa annua is believed to have had 
two ancestors, Poa supina and Poa 
infirma. Both of these species are con­
sidered to be diploid organisms, and 
each carries 14 chromosomes (denoted 
as 2n=2x=14 chromosomes). Because 
they are different species, the 14 chro­
mosomes are very different between 
species and, upon hybridization, result 
in sterile offspring. A similar event 
happens when a donkey is mated with 
a horse to obtain a mule, which also is 
sterile. In plants, however, and prob­
ably due to their modularity, events 
may occur which restore fertility by 
doubling all of a cell’s chromosomes. 
This is the situation with Poa annua. 
The two species, Poa supina and Poa 
infirma, mated to produce a sterile 
hybrid plant (ln=2x=14 chromosomes) 
whose chromosome number spon­
taneously doubled to yield Poa annua 
(2n=4x=28 chromosomes).

Such hybridization and doubling 
events generate extreme amounts of 

JANUARY/FEBRUARY1999 

11

variability (i.e., 100%). The level of this 
variability is reduced by 50% within a 
particular strain after every generation 
of self-pollination. Thus, after the first 
generation of selfing, the amount of 
variability is reduced to 50%; the 
second reduces it to 25%; the third to 
12.5%, and so on. A similar reduction 
in variability is necessary after making 
hybrids between distinct, true-breed­
ing strains of greens-type Poa annua. 
Thus, after mating two different strains 
of Poa annua, it takes a minimum of 
six to eight generations before we re­
gain strains that are uniform, stable,

produce them. In fact, the selection 
pressures of the green environment are 
so intense that we believe we are start­
ing to observe a “reverse” evolutionary 
process that is resulting in the appear­
ance of the original interspecific hybrid 
(ln=2x=14 chromosomes). These 
unique specimens have only half the 
amount of DNA of Poa annua and 
represent some of the densest, finest, 
highest quality strains we’ve observed 
to date. Like the mule, however, these 
unique strains are sterile, and our 
breeding program is investigating re­
search avenues that may enable us to 

Challenges such as seedhead production, disease and insect resistance, and rooting 
potential need to be resolved in the breeding program.

and true breeding. In producing one 
generation every two years, which in­
cludes some limited trial evaluation, it 
is easy to see that artificially breeding 
improved strains of Poa annua is a 
long-term process. However, much of 
this work has already occurred on old 
golf greens because of natural hybridi­
zations, close mowing heights, the 
traffic provided by golfers, and the com­
petition among all grasses for the 
limited resources of a golf green 
environment. With every generation, 
Poa annua has been evolving to toler­
ate low cutting heights and increased 
foot traffic. This evolutionary process 
has resulted in strains we call greens- 
type Poaannua.

Such greens-type Poas probably 
were not present back in the early 
1900s when bentgrass was chosen as 
the grass to plant on golf course putting 
greens because it has taken the past 100 
years of evolution and competition to 

12 USGA GREEN SECTION RECORD

restore fertility while retaining their 
favorable attributes. Thus, in addition 
to simply collecting samples of Poa 
annua that have evolved naturally on 
golf greens, we also have begun the 
long-term process of actively breeding 
greens-type Poa annuas using tradi­
tional methods and some of the newer 
molecular genetic technologies.

Growing Limitations

Just as the farmer who decided to 
grow dandelions for the natural food 
market discovered, when a weed is 
grown as a crop you find out your 
indestructible weed has a list of prob­
lems all its own that need to be over­
come. One of the major limitations of 
growing Poa annua is its limited range 
of favorable growing temperatures. Poa 
annua tends to grow poorly when 
temperatures are either too hot or too 
cold. As part of our breeding program, 

we are actively investigating the varia­
bility within the species for tolerance 
to extreme temperatures. Working on 
temperature tolerance in plants is not 
as straightforward as it might seem. 
To simply plunge a grass plant into an 
extreme temperature does not allow the 
plant’s natural defense mechanisms to 
incrementally adjust. In order to gain 
insight into Poa annual tolerance 
mechanisms, we first need to acclima­
tize the plants before exposing them to 
extreme temperatures. To evaluate for 
cold tolerance, the Poa annuas are 
pre-hardened at 2°C for one to two 
weeks, followed by -2°C for another 
two weeks. Temperatures are then 
lowered down to critically cold levels.
This cold-tolerance research is being 
performed as a collaborative research 
project with the Canadian Turfgrass 
Research Foundation (CTRF), Laval 
University at Quebec, and Agricultural 
Canada at St. Foy. At Laval University, 
co-investigator Julie Dionne’s prelimi­
nary findings suggest that there are 
differences among greens-type Poa 
annuas in their ability to tolerate 
critically cold temperatures. The least 
cold-tolerant Poa annua showed a 
50% survival rate at 1.4°F, while the 
most cold-tolerant Poa annua showed 
a 50% survival rate down to -8.3°F. 
These tolerances are far less than 
creeping bentgrass, which is capable of 
demonstrating 50% survival down to 
-18.4°F. Only by discovering differences 
among Poa annuas will we be able to 
discover the underlying genetic and 
physiological mechanisms responsible 
for these differences, which might en­
able us to improve Poa annua’s in­
herent cold-tolerance mechanisms.

Throughout our work, it has been 
helpful to look at other systems of cold 
tolerance. Fortunately, one of the only 
two plants known to grow in Antarc­
tica happens to be a grass — Antarctic 
hairgrass (Deschampsia antarcticd). 
Antarctic hairgrass has quite literally 
only a few hours each day during the 
middle of summer in which tempera­
tures get above freezing, enabling 
photosynthesis to occur. The remark­
able finding is that there seems to be no 
“silver bullet” cold-tolerance mecha­
nism at work inside Antarctic hairgrass. 
Rather, cold tolerance is ascribed to 
a substantial ability to store naturally 
occurring carbohydrates called fructans.
We also have begun to observe dif­
ferences in fructan levels among the 
Poa annuas and are currently corre­
lating this information with our cold­
tolerance studies. If it’s discovered that 

fructan storage is a major component of 
cold tolerance in Poa annua, as it 
appears to be in Antarctic hairgrass, 
then we may be able to breed for the 
ability to store fructans and thereby 
begin to realize improved tolerance to 
cold temperatures in Poa annua.

Tolerance to Ice

Another important area of our cold­
tolerance research is to determine Poa 
annual tolerance to ice coverage. 
Many factors may be related to Poa’s 
ability to tolerate ice coverage. Crown 
hydration, lack of oxygen, release and 
buildup of toxic gases, the frequency 
and modulation of freeze-thaw cycles, 
duration of coverage, and carbohydrate 
reserves are all potential factors that 
may work independently or may inter­
act to yield the observation that, in 
general, ice coverage often kills Poa 
annua.

Our research to date has been in­
conclusive. During some experiments 
the Poa annua dies, in others it does 
not. Could other factors be responsible 
or interacting with those previously 
mentioned? What are the hydro­
dynamics at the interface between the 
soil and ice? Is it just ice or is it a 
combination of ice over a saturated 
soil that kills Poa? Are native soils 
more susceptible to ice damage than 
are sand-based greens?

Currently, we have more questions 
than answers. Even so, we know that 
visual differences in ice may appear. For 
example, warm water freezes slowly 
and is generally free of trapped air, 
making it appear clear or transparent 
(i.e., black ice); cold water freezes 
more quickly and often has pockets 
of trapped air which make it appear 
cloudy or white. Perhaps it is not 
whether ice is black or white that is 
important, but rather how quickly 
water freezes and what the potential is 
for soil drainage to occur before ice 
develops. We are only beginning to 
establish those conditions in which we 
are capable of killing Poa annua re­
peatedly with ice coverage at slightly 
freezing temperatures (approximately 
27°F). Once these conditions are 
established, we will begin to screen the 
Poa annua collection for differential 
tolerances. After tolerant and suscep­
tible strains are identified, we will begin 
to examine physiological differences to 
explore ways in which to enhance Poa 
annual tolerance to ice coverage.

Heat Tolerance

On one of my collection trips along 
coastal Virginia, a superintendent re­

marked that “Poa annua is the greatest 
grass ... for nine months of the year.” 
Heat tolerance and Poa annua may 
seem like contradictory terms, but the 
superintendent who made that state­
ment had greens consisting of 80% Poa 
annua. Many northern regions where 
Poa annua dominates also experience 
some measure of summer heat stress 
during July and August. Thus, any 
improvement that might be made 
towards enhancing the heat tolerance 
of greens-type Poa annua would 
benefit those superintendents and 
golfers who have Poa annua greens.

Generation after generation, Poa annua 
has continuously evolved to gain a 
competitive edge and improved shoot 
density.

Like the above two projects, screen­
ing for differences in heat tolerance 
among the collections is our starting 
point. Heat benches containing sand 
root zones and adjustable heating units 
serve as our coliseum where Poa 
annua is forced to wage battle against 
high temperatures (approximately 
113°F). Will Poa annua with deeper 
roots win out, being able to transpire 
and thus cool off more effectively, or 
do some Poas have root/crown pro­
teins that function slightly better at 
elevated temperatures? Only time will 
tell.

Other Complicating Factors

Greens-type Poa annua has many 
additional problems that ultimately 
need to be resolved: seed head pro­
duction, disease and insect resistance, 
rooting potential, and determining best 

management practices. Each of these 
areas, as well as extreme temperature 
tolerances, are beginning to be ad­
dressed in our breeding program. By 
screening the increasing number of col­
lected strains, and through the eventual 
screening of new genetic combinations 
resulting from our hybridization breed­
ing program, we hope to develop large 
enough supplies to offer turfgrass sci­
ence colleagues around the country a 
chance to test and evaluate the elite 
strains of greens-type Poa annua. The 
ultimate goal of developing commer­
cially available sources of greens-type 
Poa annua is not to replace bentgrass 
as a preferred grass for putting surfaces, 
but rather to offer an additional tool 
for superintendents to have at their 
ready, especially in regions and climates 
where Poa annua is simply a better 
choice of grass for use as a putting 
surface. For many, there is no other 
choice than to commit to “For richer, 
for Poa.”

References
Beard, J. B. 1964. Effects of ice, snow, and 
water covers on Kentucky bluegrass, annual 
bluegrass, and creeping bentgrass. Crop Sci. 
4:638-640.

Beard, J. B. 1970. An ecological study of 
annual bluegrass. USGA Green Section 
Record, March, pp. 13-18.

Beard, J. B. 1996. Low-temperature kill and 
ice sheets. Golf Course Management, May, 
pp. 60-64.

Beard, J. B., P. E. Rieke, A. J. Turgeon, and 
J. M. Vargas. 1978. Annual bluegrass (Poa 
annua L.) description, adaptation, culture, 
and control. Res. Rep. 352. Michigan State 
University, East Lansing. 31 p.

Bittenbender, H. C., and G. C. Howell, Jr. 
1974. Adaptation of the Spearman-Kaber 
method for estimating T50 of cold-stressed 
flower buds. J. Amer. Soc. Amer. Sci. 
99:187-190.

Bjorkman, O., M. R. Badger, and P. A. 
Armond. 1980. Response and adaptation of 
photosynthesis to high temperatures, p. 
233-249. In Adaptation of plants to water 
and high-temperature stress. John Wiley 
and Sons Publishers, Toronto.

Castonguay, Y, S. Laberge, and P. Nadeau. 
1993. Freezing tolerance and alteration of 
translatable mRNAs in alfalfa hardened at 
subzero temperatures. Plant Cell Physiol. 
34:31-38.

Cordukes, W. E. 1977. Growth habit and 
heat tolerance of a collection of Poa annua 
plants in Canada. Can. J. Plant Sci. 57:1201- 
03.

Dionne, J., and Y. Desjardins. 1996. What’s 
happening under the blanket. Greenmaster, 
November.

JANUARY/FEBRUARY1999 

13

Edwards, J. A., and R.I.L. Smith. 1988. 
Photosynthesis and respiration of Colo- 
banthus quitensis and Deschampsia ant- 
arctica from the Antarctic. British Antarctic 
Survey Bulletin 81:43-63.

Fehr, W. R. 1991. Principles of Cultivar 
Development. Vol. 1. Theory and Tech­
nique. Iowa State University. Macmillan, p. 
536.

Gibeault, V. A. 1970. Perenniality in Poa 
annua L. Ph.D. Dissertation. Oregon State 
University, p. 124.

Hetherington, P. R., B. D. McKersie, and A. 
Borochov. 1987. Ice encasement injury to 
microsomal membranes from winter wheat 
crowns. Plant Physiol. 85:1068-1072.

Huff, D. R. 1996a. Poa annua for golf 
course greens. Grounds Maintenance, 
January, pp. G2-G10.

Krause, G. H., and E. Weis. 1984. Chloro­
phyll fluorescence as a tool in plant physi­
ology. II. Interpretation of fluorescence 
signals. Photosynth. Res. 5:139-157.

Krause, G. H., and S. Somersalo. 1989. 
Fluorescence as a tool in photosynthesis 
research: application in studies of photo­
inhibition, cold acclimation, and freezing 
stress. Phil. Trans. R. Soc. Lond. B 323:281- 
293.

Li, P. H. 1984. Subzero temperature stress 
physiology of herbaceous plants. Hort. Rev. 
6:373-416.
Lush, W. M. 1988. Biology of Poa annua 
in a temperate zone golf putting green 
(Agrostis stolonifera/Poa annua). II. The 
seed bank. Journal of Applied Ecology 
25:989-995.
McKersie, B. D., and Y. Y. Leshem. 1994. 
Anaerobic stress-flooding and ice-encase­
ment. p. 15-54. In Stress and stress coping 
in cultivated plants. Kluwer Academic 
Publishers, Boston.
Meyer, W. A., J. A. Murphy, D. A. Smith. 
Response of cool-season turfgrass to a 
novel traffic simulator. 89th ASA-CSSA- 
SSSA. Anaheim, California. Agronomy 
Abstracts.
Minner, D. D., P. H. Demoeden, D. J. 
Wehner, and M. S. McIntosh. 1983. Heat 
tolerance screening of field-grown cultivars 
of Kentucky bluegrass and perennial rye­
grass. Agron. J. 75:772-775.
Mowforth, M. A., J. P. Grime. 1989. Intra­
population variation in nuclear DNA 
amount, cell size, and growth rate in Poa 
annua L. Functional Ecology 3:289-294.
Osteryoung, K. W, and E. Vierling. 1994. 
Dynamics of small heat shock protein 
distribution within the chloroplasts of 
higher plants. Journal of Biological 
Chemistry 269:28676-28682.

Dy. David Huff has collected thousands of Poa annua samples throughout the United 
States. A pile of Poa annua this large will make any plant breeder smile.

14 USGA GREEN SECTION RECORD

Smillie, R. M., and S. E. Hetherington. 
1983. Stress tolerance and stress-induced 
injury in crop plants measured by chloro­
phyll fluorescence in vivo. Plant Physiol. 
72:1043-1050.
Tompkins, D, C. Bubar, E. Toews, and J. 
Ross. 1995. Physiology of low temperature 
injury with emphasis on crown hydration in 
Poa annua L. In Prairie turfgrass research 
centre annual report 1995.
Wallner, S. J., M. R. Beewar, and J. D. Butler. 
1982. Measurement of turfgrass heat toler­
ance in vitro. J. Hortic. Sci. 107:608-613.
Warwick, S. I. 1979. The biology of 
Canadian weeds. Poa annua L. Can. J. 
Plant Sci. 59:1053-1066.

Principal Project Investigators
Dr. Yves Desjardins, Laval University
Ms. Julie Dionne, Laval University
Dr. Yves Castonguay, Agriculture Canada 

Research Center, Ste-Foy
Dr. Daniel Knievel, Penn State
Mr. George Hamilton, Penn State
Mr. Eric Lyons, Penn State
Mr. Roy Knupp, Penn State
Mr. Jim Ross, Prairie Turfgrass Research 

Centre

Many thanks to the numerous golf course 
superintendents who have allowed collec­
tions of Poa annua from their greens and 
to the USGA Green Section agronomists 
who assisted with the collection trips.

Donating Poa annua
If you or someone you know has greens- 
type Poa annua and would like to have 
its merits examined, the PSU Poa annua 
breeding program would like to receive 
your samples. Begin by collecting one or 
two aerification tine cores from each 
“patch” you wish to sample (no limit 
here), wrap in a moist paper towel, 
enclose in a zip-lock bag, and label each 
bag with your course name and hole 
location (example: Oakmont 18G). Send 
by overnight mail to:
David R. Huff
Assistant Professor
Turfgrass Breeding and Genetics 
Dept, of Agronomy, 116 ASI Bldg. 
Pennsylvania State University 
University Park, PA 16802
Phone: 814-863-9805
Fax: 814-863-7043
E-Mail: drhl5@psu.edu

Poa annua is a reality on most cool-season 
golf courses in America. DR. DAVID 
HUFF, assistant professor in turfgrass 
breeding and genetics at Pennsylvania 
State University, hopes to improve on 
what’s available.

ON COURSE WITH NATURE
Maintain The Best Irrigation Water
Quality On The Golf Course

Consider the use of a floating intake structure.

by MILES M. (BUD) SMART, Ph.D.

B. Cross Section of Lake Showing Stratification 

Upper Strata of Lake: Lower suspended solids, 
lower oxygen demand, exposure to light

Lower Strata of
Lake: Higher suspended 
solids, higher oxygen demand, 
large quantities of organic material settling 
from upper waters, very limited exposure to light

— Stratification

C. Cross Section of Lake Showing Floating Intake Structure

Float —

Intake 
approximately 
1' to 2' below 
surface

— Flexible piping

WATER MANAGEMENT is 

one of the significant keys to 
the success of golf course 
management. Properly managed water 

resources provide good quality irriga­
tion water, aesthetically pleasing ponds 
and streams, appropriate stormwater 
treatment, and no offsite surface- or 
ground-water pollution problems. 
Properly managed water resources also 
provide habitat for a variety of animal 
and plant inhabitants.

One technique used to maintain the 
best possible quality irrigation water is 
to install a floating intake structure for 
the irrigation system. Why does a float­
ing intake structure, compared to a 
bottom structure, make sense? Because 
over the course of a year, an irrigation 
lake may go through several physical 
changes that result in the poorest water 

quality being located in the lower strata 
of the lake, right where the irrigation 
intake structure is located. Using poor 
quality irrigation water may result in 
turf damage or, at the least, difficult 
conditions for turf to thrive. This may, 
in turn, require the use of more fertil­
izers, pesticides, maintenance time, 
and equipment use, or even more 
water. Using the best quality irrigation 
water is good for the golf course and 
good for nature. Additionally, the 
intake structure is located one to two 
feet under the surface and is generally 
not even noticed.

Audubon International, working 
with members of the Cooperative 
Sanctuary and Signature programs, has 
observed many cases where an intake 
structure located near the bottom of 
a lake resulted in turf and aesthetic 

problems on golf courses. In one 
example, each time the irrigation sys­
tem was used, a rotten-egg smell 
permeated the course, the sidewalks 
where irrigation spray drifted turned 
a mottled red, tree trunks that were 
sprayed turned slimy and black, and 
the greens were dying. These situations 
were the result of irrigating with less 
than desirable quality water.

The irrigation lake can be affected by 
many factors that impact the quality of 
water. Simply because irrigation lakes 
(ponds, streams, etc.) are at the bottom 
of drainage basins, and because water 
runs downhill to the lake, these water 
bodies are influenced by meteorologic, 
geologic, and biologic inputs, via the 
terrestrial watershed or directly from 
the atmosphere. In addition to these 
outside influences, there are several 
internal characteristics that are impor­
tant to its overall health and stability, 
and thus important to good irrigation 
water quality. Characteristics include 
lake regions, light, heat (thermal strati­
fication), and nutrients. Water quality 
also dictates the abundance of algae, 
which can further influence water 
quality.

Light: Light is the major energy 
source to aquatic ecosystems, and light 
is the major source of heat to a lake. 
Absorption of light and its dissipation 
as heat influence the thermal structure, 
water stratification, and circulation 
patterns of lakes. Ultimately, these 
factors also can impact the aquatic 
organisms that live in the water.

Upper layers of water bodies are 
generally warmer than the lower layers 
because of heating by solar radiation. 
During the summer (or summer-like 
temperatures in the southern tier of 
states), temperature differences be­
tween upper and lower waters can 
become great enough that these waters 
are effectively separated. Separation is 
due to density differences that are 
caused by differences in water tempera­
ture (called thermal stratification). The 
upper waters are warm and mixed by 

JANUARY/FEBRUARY1999 

15

the wind to an approximately uniform 
temperature (called the epilimnion). 
Bottom waters are cool, heavier, and 
not affected by wind (called the hypo­
limnion). Separating the two regions is 
an intermediate zone, where tempera­
ture drops rapidly with increasing 
depth (called the metalimnion).

Thermal Stratification: Once a lake 
is thermally stratified, a number of 
changes take place in the lake. One of 
the most important is the dissolved 
oxygen levels. Oxygen and the levels 
present in an irrigation lake can have a 
dramatic effect on the life of a lake and 
its water quality. Aquatic organisms 
require oxygen to survive and, in its 
absence, organisms either move from 
the oxygen-poor area or die. Many 
studies have documented changes in 
biological communities with a shift in 
dissolved oxygen concentrations.

Dissolved oxygen in a lake comes 
from photosynthesis or from exchanges 
with the atmosphere at the water’s 
surface. During thermal stratification, a 
delineation occurs between the oxygen­
rich water at the top of the lake and the 
oxygen-poor water at the bottom. This 
reduction or lack of dissolved oxygen 
also can establish a series of chemical 
reactions that further reduce water 
quality. Examples, such as sulfate be­
ing converted to hydrogen sulfide, in­
soluble iron being converted to soluble 
forms, suspended material concentra­
tions increasing, and decomposition of 
materials that settle from the surface to 
the bottom being slowed (algae, grass 
clippings, leaves), can make the bottom 
water an inappropriate medium for 
supporting aquatic life. It also makes a 
very poor source of irrigation water.

The irrigation intake, traditionally 
located in the bottom water region of 
the lake, generally provides your golf 
course with the poorest quality water. 
In our example from above, the rotten- 
egg smell is from the hydrogen sulfide, 
the red mottled sidewalks result from 
an increase in the reduced form of iron 
(ferrous) in the bottom water that is 
oxidized (ferric, red color) when the 
irrigation water comes in contact with 
the atmosphere, and the slimy black 
material on tree trunks is the partially 
decomposed organic material that was 
from both the drainage basin and the 
lake. The greens also are stressed by the 
partially decomposed organic matter as 
it competes with the turf for oxygen 
at the soil surface. On many of the 
greens, stress is so great that the turf 
can’t survive and may have to be 
replaced.

16 USGA GREEN SECTION RECORD

An overabundance of algae also can 
become a hindrance to water quality 
and make a floating intake structure 
important. Water bodies have algae that 
occur naturally and are an important 
component of the aquatic food chain. 
However, at some point a healthy algal 
population may actually become an 
algal bloom that may impair the use­
fulness of a water body for irrigation. 
The cause of most algal problems is 
an abundance of phosphorus in the 
water of freshwater lakes (in marine or 
estuary systems, nitrogen may be more 
important).

Algae are particularly well adapted to 
take advantage of high nutrient con­
centrations (particularly phosphorus), 
warm water, and sunshine, and they 
reproduce exponentially. The result is 
an algal bloom, often distinguished by 
the pea-soup appearance of water that 
results from large quantities of algae.

Algal blooms cause many different 
problems, but the primary concern for 
irrigation water occurs when the algae 
die at nearly the same time. A die-off 
of algae occurs for many different envi­
ronmental reasons (overcast skies 
reducing light intensities and a cold 
snap are among the two most common) 
and may also occur when chemicals 
are applied for algal control. A die-off 
is often easily observed — one day the 
water is green, and the next day the 
water is brown. The intense green of 
the algal bloom is from the chlorophyll 
in the algae. The dying and dead algae 
rain from the upper water to the lower 
water. In a stratified lake, an algal 
bloom followed by a die-off places a 
large oxygen demand on the water, 
increases the organic load and sus­
pended solids load, and in general 
makes irrigation water unsuitable for 
use. Putting grass clippings in the irri­
gation lake also may cause symptoms 
similar to an abundance of algae — 
oxygen stress, organic loading, and 
increased suspended solids.

A floating intake structure is an 
economical way to get the best possible 
irrigation water for your golf course 
and maintain the ability to obtain water 
when water levels drop. A floating in­
take structure also reduces the possi­
bilities of sediment problems that can 
occur with a bottom intake structure. 
A floating intake structure can be pur­
chased or can be built and installed by 
a local machine shop.

There are two questions that are 
frequently asked by golf course super­
intendents concerning floating intake 
structures: 1) Can I use an aerator sys­

tem instead of a floating intake? 2) My 
irrigation lake cycles every ten days 
(has a hydraulic retention time of ten 
days), so do I need to have a floating 
intake?

In answer to the first question, with 
the use of fountains, the objective is to 
circulate enough water to ensure mix­
ing of the lake. Fountains generally do 
not have the depth or breadth of circu­
lation to be effective as stand-alone 
systems for the irrigation lake. In 
smaller, shallower ponds they may be 
adequate to prevent stagnation and 
reduce the potential for massive algal 
blooms (algae reproduce rapidly in 
quiet waters, so stirring things up may 
reduce the severity of the bloom). 
Deep-water aerators may be useful, but 
this depends on the volume of the lake 
and the size of the aeration system. 
Injection of air through piping at the 
bottom also may be of help in reducing 
stratification; again, this depends on 
the size of the system relative to the 
volume of water. Injection of air rather 
than ozone is recommended because of 
the cost associated with ozone genera­
tion. Air contains enough oxygen 
(approximately 20.9%) to reduce 
stratification and aerate bottom waters. 
None of these aerator systems, how­
ever, effectively handle potential sedi­
mentation problems.

An irrigation lake that cycles every 
ten days probably will not have sig­
nificant thermal stratification, due 
simply to the constant mixing of the 
lake waters. A floating intake may 
make sense in these cases to reduce the 
potential for problems associated with 
sediment buildup around the intake.

Incorporating the use of a floating 
intake structure makes sense on many 
different levels. It can decrease the 
probabilities that your turfgrass will 
be negatively affected by poor water. 
Because the intake structure floats, it 
allows for continued availability of the 
best quality of water under many dif­
ferent situations and occurrences that 
a water source is subjected to season­
ally. Using the best quality irrigation 
water is good for the golf course and 
good for nature.

DR. BUD SMART is the Director of the 
Department of Environmental Planning 
at the Siena College-Audubon Inter­
national Institute. The Institute conducts 
research on human-managed landscapes 
and provides technical assistance to 
members of Audubon International’s 
Cooperative Sanctuary and Signature 
programs.

NEWS NOTES

1999 Turf Advisory Service Changes

Following four years of maintaining 
the same fee structure for our Turf 
Advisory Service, 1999 will bring a 
small increase. For those of you 
budgeting for the next season, our fee 
structure will be $1,300 for a half-day 
visit and $1,800 for a full day.

As an even better value, plan ahead 
to take advantage of the prepayment 
discounts. A $300 discount is offered 
for both half-day and full-day visits if 
the visit is paid before May 15,1999. As 
always, visits can be scheduled to occur 
at any time during the season to meet 
your needs.

The USGA Green Section is the only 
agency in the country devoted solely to

golf course turf, its playing conditions, 
and its management. The cost of a TAS 
visit is a flat fee that covers agronomic 
aspects of the visit, the preparation of 
a detailed written report, as well as all 
of the related expenses, such as trans­
portation, food, and lodging. Whether 
dealing with diseases, soil problems, or 
day-to-day management of the golf 
course, the valuable experience offered 
to your golf course by our 16 agrono­
mists cannot be matched by any 
individual or agency anywhere.

Contact your regional Green Section 
office to obtain more information about 
the Turf Advisory Service and to 
schedule your visit for 1999.

USGA Contributes $1 Million 
to Turfgrass Information Center
The USGA has announced that it 
will contribute $1 million over the next 
five years to help establish an endow­
ment to support and expand the Turf­
grass Information Center (TIC) located 
at Michigan State University.

Clifford H. Haka, Director of Libraries, 
Michigan State University.

Since 1992, TIC has obtained most of 
its funding from Michigan State Uni­
versity (MSU), with a modest contri­
bution from annual subscriptions from 
users. The Development Department at 
MSU will establish a campaign to raise 
$5 million for the TIC endowment, 
which includes the USGAs $1 million 
contribution.

If at least $2 million is raised, then 
the TIC database will be made available 
free of charge to all Internet users. 
Additional funds raised would be 
utilized to expand full-document 
availability of information from the 
database, provide video and photo­
graphic files, and expand other services 
to the turfgrass industry and the game 
of golf.

The USGA originally provided more 
than $700,000 to help establish and 
expand the TIC database from its 
inception in 1982 to 1992.

Individuals and organizations wish­
ing to support the endowment can 
contact Clifford H. Haka at (517) 355- 
2341 or Michigan State University 
Library, 100 Library, East Lansing, MI 
44824-1048.

Questions about the USGAs contri­
butions to the Turfgrass Information 
Center may be directed to Jim Snow, 
National Director of the USGA Green 
Section, at (908) 234-2300.

“The USGAs Turfgrass and Environ­
mental Research Committee decided to 
allocate $200,000 annually for the next 
five years from its research budget to 
support TIC,” Joe England, Chairman 
of the USGAs Green Section Commit­
tee, said.

“TIC is simply the world’s best library 
of turfgrass and golf course mainte­
nance information. The USGAs sup­
port of this one-of-a-kind collection 
will help ensure the continued availa­
bility of this critical resource for gen­
erations to come,” England concluded.
TIC contains a computerized data­
base that has abstracts of more than 
58,000 entries, including books, news­
letters, periodicals, bulletins, and other 
publications. It is used by university 
faculty, golf course superintendents, 
turfgrass students, USGA Green Sec­
tion staff, and others interested in the 
proper maintenance and management 
of golf courses.

“The World Wide Web now makes 
the delivery of the information within 
the Turfgrass Information Center im­
mediately accessible throughout the 
world. This valuable gift from the 
USGA points to the day when the TIC 
will be universally available,” said 

Physical Soil Testing 
Laboratories*
The following laboratories are accredited 
by the American Association for 
Laboratory Accreditation (A2LA), having 
demonstrated ongoing competency in 
testing materials specified in the USGAs 
Recommendations for Putting Green 
Construction. The USGA recommends 
that only A2LA-accredited laboratories 
be used for testing and analyzing 
materials for building greens according to 
our guidelines.

BROOKSIDE
LABORATORIES, INC.
308 S. Main Street
New Knoxville, OH 45871 
Attn: Mark Flock 
(419) 753-2448
(419) 753-2949 FAX

EUROPEAN TURFGRASS 
LABORATORIES LIMITED
3 Cunningham Road 
Springkerse Industrial East 
Stirling FK7 7SL Scotland 
Attn: John Souter 
(44) 1786-449195
(44) 1786-449688 FAX

N.W. HUMMEL & CO.
35 King Street, P.O. Box 606 
Trumansburg, NY 14886
Attn: Norm Hummel 
(607) 387-5694 
(607) 387-9499 FAX

THOMAS TURF 
SERVICES, INC.
1501 FM 2818, Suite 302 
College Station, TX 77840-5247 
Attn: Bob Yzaguirre I Jim Thomas 
(409) 764-2050
(409) 764-2152 FAX

TIFTON PHYSICAL SOIL 
TESTING LABORATORY, INC.
1412 Murray Avenue 
Tifton, GA 31794 
Attn: Powell Gaines 
(912) 382-7292 
(912) 382-7992 FAX

TURF DIAGNOSTICS 
AND DESIGN, INC.
310-A North Winchester Street 
Olathe, KS 66062 
Attn: Chuck Dixon
(913) 780-6725 
(913) 780-6759 FAX

* Revised January 1998. Please 
contact the USGA Green Section 
(908-234-2300) for an updated list 
of accredited laboratories.

JANUARY/FEBRUARY1999 

17

United States Golf Association 
Green Section Educational Program 
Sunday, February 14,1999 
Orlando Convention Center
Orlando, Florida
Experience Spoken Here
Moderator: James T. Snow, National Director, USGA Green Section

8:30 a.m. Welcome

Joe England, USGA Executive Committee

8:35 a.m. The Best Turf Tips from the Green Section Staff

Patrick O’Brien, Director, Southeast Region
Brian Maloy, Agronomist, Mid-Continent Region
Darin Bevard, Agronomist, Mid-Atlantic Region
Bob Brame, Director, North-Central Region
Matt Nelson, Agronomist, Northeast Region

8:55 a.m. Organic Fact and Fallacies

Dr. Noel Jackson, University of Rhode Island
The mystical world of biological controls contains a lot of fact and fiction.
Dr. Jackson will discuss what to look for when making decisions regarding 
products available on the market.

9:25 a.m. More of the Best Turf Tips

Jim Skorulski, Agronomist, Northeast Region
Keith Happ, Agronomist, Mid-Atlantic Region
John Foy, Director, Florida Region
Mike Huck, Agronomist, Southwest Region
Chris Hartwiger, Agronomist, Southeast and Florida Regions
Paul Vermeulen, Director, Mid-Continent Region

9:50 a.m. It’s the Same Game, But How It’s Changed!
Frank Thomas, Director, USGA Test Center
Golf equipment issues have been a major discussion topic in the golf world.
Hear about the true impact of equipment from the head of the USGA Test Center.

10:25 a.m. Presentation of the USGA Green Section Award

Dr. Noel Jackson, University of Rhode Island

10:35 a.m. On To The Next Millennium

Buzz Taylor, President, United States Golf Association
A look into the future of golf as we approach the year 2000.

10:50 a.m. The Best Turf Tips Keep on Coming

David Oatis, Director, Northeast Region
Pat Gross, Director, Southwest Region
Bob Vavrek, Agronomist, North-Central Region
Stan Zontek, Director, Mid-Atlantic Region
Larry Gilhuly, Director, Northwest Region

11:10 a.m. Closing Remarks

18 USGA GREEN SECTION RECORD

1999 GREEN SECTION 
NATIONAL & REGIONAL CONFERENCES

NATIONAL CONFERENCE

February 14 Orange County Convention Center

Orlando, Florida

FLORIDA REGION

April 27 
April 29 

Orlando Airport Marriott
Palm Beach Gardens Marriott

MID-ATLANTIC REGION

March 16  Woodholme Country Club

MID-CONTINENT REGION

March 16 
March 17 
March 18 
March 22 Embassy Club at Capital Square

Old Warson Country Club
Brookhollow Golf Club
Lakeside Country Club

NORTH-CENTRAL REGION

January 26 Indianapolis Convention Center
March 16 Wayzata Country Club

NORTHEAST REGION

March 19  Wesleyan College
March 23 
March 25 

Oak Hill Country Club
USGA Golf House

SOUTHEAST REGION

March 9 
March 17 
March 31 

Atlanta Athletic Club
Pinehurst Country Club
Richland Country Club

NORTHWEST REGION

Hillcrest Country Club
March 22 
March 29 
Fircrest Country Club
April 12*  Waialae Country Club

SOUTHWEST REGION

March 15 
March 23 
March 24 
March 30 
March 31 

*Tentative

Spanish Trail Country Club
Orange Tree Resort
Lakewood Country Club
Industry Hills Golf Club
Castlewood Country Club

Orlando, Florida 
Palm Beach, Florida

Baltimore, Maryland

St. Louis, Missouri 
Dallas, Texas 
Houston, Texas 
Des Moines, Iowa

Indianapolis, Indiana 
Wayzata, Minnesota

Middletown, Connecticut 
Rochester, New York 
Far Hills, New Jersey

Atlanta, Georgia 
Pinehurst, North Carolina 
Nashville, Tennessee

Boise, Idaho
Tacoma, Washington 
Honolulu, Hawaii

Las Vegas, Nevada 
Phoenix, Arizona 
Denver, Colorado 
Industry Hills, California 
Pleasanton, California

JANUARY/FEBRUARY1999 

19

ALL THINGS CONSIDERED

The Seven Dirty Words of 
Golf Course Maintenance

Watch your language!

by PATRICK GROSS

THERE ARE certain words that 

should never be mentioned in 
public, especially at a golf course. 
To do so would constitute a serious 

breach of decorum and good manners. 
Golf, being a game of etiquette and 
gentility, requires that certain social 
graces be observed. The following 
seven words are listed as a public ser­
vice to golfers and superintendents to 
help you avoid social embarrassment.

Aerification: Does this sound 
familiar? “Just when the greens start 
getting good, they plug ’em and mess 
’em up.” You would think superinten­
dents aerify on purpose just to upset 
golfers. The truth is, if you want healthy 
grass, you need to aerify. This process 
removes thatch, relieves compaction, 
stimulates root growth, and improves 
air and water movement within the soil. 
Aerification also helps prevent the dis­
cussion of some of the following dirty 
words.

Brown: Unfortunately, there is no 
room in the American golfer’s vocabu­
lary for the word brown. Grass must 
be green — perfectly, uniformly lush 
green, even if it means over-watering 
and plugged lies in fairways. There’s 
nothing wrong with green grass, but 
there’s nothing wrong with a little tinge 
of brown, either. It’s a good sign that 
the course is not over-watered.

Ast: No matter how fast greens 
are, they are never fast enough. More 
time, energy, and money have been 
spent over the years to produce fast 
greens, but golfers want still more. 
Gradually, the pace of play grinds to a 
halt as golfers plum-bob their fourth 
putt. In the end, the quest for fast 
greens leaves in its wake dead grass 
and unemployed superintendents. 
Whatever happened to the goal of 
smooth greens with reasonable pace?

20 USGA GREEN SECTION RECORD

Bunkers: Golfers will tell you 
bunkers are always “too” something — 
too hard, too soft, too wet, too dry, too 
shallow, too deep, etc. All I can say is, 
“Too bad.” Bunkers are hazards. 
Something is seriously wrong when 
courses are spending more time and 
money maintaining bunkers than 
greens.

Trees: People love to see trees on 
golf courses. Trees are beautiful, they 
are challenging obstacles, and they 
provide some degree of safety. But 
trees and turf just can’t seem to get 
along. Excessive shade, root encroach­
ment, interference with irrigation, and 
blocked air movement are just some of 
the problems caused by trees. When 
superintendents suggest removing trees 
to grow healthier turf, they are met with 
strong opposition. I have heard golfers 
say, “Do you know how long it took 
for that tree to reach that size and now 
you want to cut it down?” I think it is 
unfortunate that courses have suffered 
with terrible turf at the expense of 
trees. After all, the game of golf is 
played on grass.

Carts: The negative impact of golf 
carts on the playing quality of courses 
cannot be denied. Soil compaction, 
thin turf, abrasion, and wear injury 
directly affect turf quality. But if you 
suggest cart use rules or restricting 
carts to the paths, screams of protest 
can be heard throughout the course. 
Many golfers don’t pay attention to 
the rules anyway and then wonder why 
there are brown spots (see dirty word 
#2). A significant amount of money is 
spent at courses each year for ropes, 
stakes, directional signs, and marking 
paint to restrain carts, not to mention 
the maintenance programs to correct 
the damage. Unfortunately, many 
courses are addicted to the revenue

produced by the rental of carts, but I 
wonder if the revenue is enough to 
offset the damage caused to the golf 
course?

Rebuild: When all the agronomic 
alternatives have been exhausted and 
you still cannot grow healthy turf on 
the greens, many superintendents and 
green committees entertain the thought 
of rebuilding the greens. But be very 
careful about saying the “R” word. 
Golfers just don’t want to hear it. To 
them it means change, it means dis­
ruption, and it means money. The 
thought of rebuilding greens becomes 
even more offensive if previous con­
struction efforts failed to solve the 
problem. Before you consider rebuild­
ing greens, make sure you are doing 
it for the right reasons. You may want 
to discuss some of the previous dirty 
words that led to the problem in the 
first place {aerification, fast, and trees'). 
Then do your homework to ensure 
that the project is done properly and 
efficiently so that golfers can get back 
to playing the game they so dearly love 
in as short a time as possible.

In closing, I beg of you to please 
watch your language the next time you 
are at the golf course. Especially avoid 
these seven dirty words, because we 
don’t want to have to bring you home 
and have mother wash your mouth out 
with soap.

PAT GROSS is the Director of the South­
west Region. He politely discusses these 
seven dirty words and more with courses 
in California, Arizona, Nevada, Utah, and 
Colorado.

USGA PRESIDENT
E Morgan Taylor, Jr.

GREEN SECTION 
COMMITTEE CHAIRMAN
C. McD. England III
P.O. Box 58 
Huntington, WV 25706

EXECUTIVE DIRECTOR
David B. Fay

EDITOR
James T. Snow

ASSOCIATE EDITOR
Kimberly S. Erusha, Ph.D

DIRECTOR OF COMMUNICATIONS
Marty Parkes

©1999 by United States Golf Association®

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GREEN SECTION RECORD (ISSN 0041-5502) 
is published six times a year in January, March, 
May, July, September, and November by the 
UNITED STATES GOLF ASSOCIATION®, Golf 
House, Far Hills, NJ 07931. Postmaster: Address 
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GREEN SECTION NATIONAL OFFICES:
United States Golf Association, Golf House
P.O. Box 708, Far Hills, NJ 07931 • (908) 234-2300 • Fax (908) 781-1736
James T. Snow, National Director
Kimberly S. Erusha, Ph.D., Director of Education

rc Ji.*

P.O. Box 2227, Stillwater, OK 74076 • (405) 743-3900 • Fax (405) 743-3910
Michael P. Kenna, Ph.D., Director

Construction Education Programs:
720 Wooded Crest, Waco, TX 76712 • (254) 776-0765 • Fax (254) 776-0227 
James F. Moore, Director

REGIONAL OFFICES:
Northeast Region:
P.O. Box 4717, Easton, PA 18043 • (610) 515-1660 • Fax (610) 515-1663
David A. Oatis, Director • Matthew C. Nelson, Agronomist
1500 N. Main Street, Palmer, MA 01069 • (413) 283-2237 • Fax (413) 283-7741 
James E. Skorulski, Agronomist

Mid-Atlantic Region:
P.O. Box 2105, West Chester, PA 19380-0086 • (610) 696-4747 • Fax (610) 696-4810 
Stanley J. Zontek, Director • Keith A. Happ, Agronomist • Darin S. Bevard, Agronomist

Southeast Region:
P.O. Box 95, Griffin, GA 30224-0095 • (770) 229-8125 • Fax (770) 229-5974 
Patrick M. O’Brien, Director
4770 Sandpiper Lane, Birmingham, AL 35244 • (205) 444-5079 • Fax (205) 444-9561
Christopher E. Hartwiger, Agronomist

Florida Region:
P.O. Box 1087, Hobe Sound, FL 33475-1087 • (561) 546-2620 • Fax (561) 546-4653 
John H. Foy, Director

Mid-Continent Region:
P.O. Box 1130, Mahomet, IL 61853 • (217) 586-2490 • Fax (217) 586-2169 
Paul H. Vermeulen, Director
4232 Arbor Lane, Carrollton, TX 75010 • (972) 492-3663 • Fax (972) 492-1350 
Brian M. Maloy, Agronomist

North-Central Region:
P.O. Box 15249, Covington, KY 41015-0249 • (606) 356-3272 • Fax (606) 356-1847 
Robert A. Brame, Director
P.O. Box 5069, Elm Grove, WI 53122 • (414) 797-8743 • Fax (414) 797-8838
Robert C. Vavrek, Jr., Agronomist

Northwest Region:
5610 Old Stump Drive N.W, Gig Harbor, WA 98332
(253) 858-2266 • Fax (253) 857-6698
Larry W. Gilhuly, Director

Southwest Region:
505 North Tustin Avenue, Suite 121, Santa Ana, CA 92705 
(714) 542-5766 • Fax (714) 542-5777
Patrick J. Gross, Director • Michael T. Huck, Agronomist

x- I' I JI< l< r W151’ I IV)-----------------

HAZARD AHEAD —

Question: We use a variety of stakes to mark our water hazards. Unfortunately, the stakes can be difficult to 
maintain and keep in place. Are there better options for marking our hazards? (New Hampshire)

Answer: A painted line can be used to define the margin of a water hazard. Several indicator stakes would 
then be placed well inside the line to help players identify from a distance whether the body of water is a 
water hazard (yellow stakes) or lateral water hazard (red stakes). Wooden indicator stakes also can be 
equipped with a metal post or spike to ease their installation. Using a painted line to define water hazards 
reduces the number of stakes required, and those stakes that are used as indicators can be placed in areas 
where they are less likely to interfere with play and mowing activities. If you use both stakes and lines, be 
sure to clarify on the local rules sheet that the lines define the hazard margins and that the stakes only 
identify the hazard.

PUTTING GREEN

Question: Our golf course is located in the mountains and we only have a six-month golf season (May through 
October). Is the fall plugging of the putting greens absolutely necessary if our membership expects high quality 
surfaces at this time? (North Carolina)

Answer: With the shorter golf season in your area, it is perfectly understandable that the membership would 
desire smooth putting surfaces throughout the play season. Double aerifying the putting greens during 
the scheduled April aeration is one option. This operation will produce twice as many holes, but not twice 
the work or twice the recovery time. Use the largest size tines possible, preferably at least % inch. Obviously, 
remove the aeration plugs and backfill the holes with sand topdressing. The putting surfaces will be bumpier 
after this double aeration, but the course is closed and you can anticipate a satisfactory recovery by the 
May opening golf date.

RENOVATION

Question: We are considering replanting our greens. One question that is frequently asked is, How quickly can 
we open the greens after we plant them? (Missouri)

Answer: Opening dates vary widely depending on many factors, including climate, planting date, 
fertilization rates, type of grass, amount of play anticipated, type of rootzone mixture, etc. A good method 
to determine whether or not the green is ready for play is to examine the green’s profile using a profile 
tool or cup changer. In order for the new turf to withstand traffic, there must be a pad or thin layer of 
organic matter between the crown of the turfgrass plant and the underlying rootzone material. This pad 
is developed as the green matures. When the pad has reached approximately !4 inch in thickness, the 
green is usually ready. As a very general rule, bentgrass takes 14 to 16 weeks of good growing weather to 
develop such a pad. Bermudagrass is slightly faster and often develops the pad over 12 to 14 weeks of 
good growing weather. Please note the phrase good growing weather. This is weather that provides ideal 
growing conditions for the turfgrass selected.