Sea Isle 2000 on desert greens: Mowing height and ... - GCSAA

RESEARCH
This research was funded in part by The Environmental Institute for Golf,
USGA and Cactus and Pine GCSA.
<strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> on desert greens:
Mowing height and nitrogen fertility
The response of <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> to mowing height and fertilizer in a desert climate may not be what you expect.
David M. Kopec, Ph.D.; James H. Walworth, Ph.D.; Jeffrey J. Gilbert, M.S.;
Greg M. Sower, M.S.; and Mohammad Pessarakli, Ph.D.
As interest has increased in turfgrasses that
can tolerate high temperatures and less-thanperfect
irrigation water, seashore paspalum
(Paspalum vaginatum) has become more popular
for golf course use. Cultivars released in
the 1970s such as Excalibur and Adelaide have
been used with some success in Southern
California, Texas and the Gulf Coast area of
the southeastern United States.
<strong>Sea</strong>shore paspalum is a warm-season grass
with a moderate growth rate that tolerates
heat, salinity and flooding. Some of its less
desirable characteristics are vegetative establishment
requirements (although a seeded
variety is now available), a tendency toward
scalping and a yellow-green turf color. One of
the most popular new cultivars, <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong>,
has a low growth habit and has been used for
greens in the humid southeastern United
States, where it is irrigated with saline water.
Scientists and superintendents who have
observed P. vaginatum in humid environments
note that it requires much less nitrogen than
most bermudagrass cultivars. It is critical to
investigate the response of newer, shorter cultivars
to frequent and close mowing and to various
application rates of nitrogen fertilization.
<strong>Sea</strong>shore paspalum on greens
We wanted to determine whether seashore
paspalum could successfully be used on a green
in a desert environment. Therefore, we conducted
a two-year test to investigate the response
of <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> to three mowing heights and to
determine the response of this grass to nitrogen
fertilization in a hot, dry climate.
Materials and methods
Test site
Starting in <strong>2000</strong>, a putting green built to
USGA recommendations with <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong>
was mowed at three mowing heights: 1 ⁄8, 5 ⁄32
Figure 1. A two-year test investigated the effects of mowing height, rolling and nitrogen fertility on desert golf course
putting greens planted with <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong>.
and 3 ⁄16 inch (3.2, 4.0 and 4.8 millimeters)
(Figure 1). Turf growing at each mowing
height received monthly applications of nitrogen
(0.25, 0.38, 0.50 or 0.75 pound nitrogen/1,000
square feet [12.2, 18.6, 24.4 or 36.6
kilograms/hectare]) during the growing season,
which is normally from May to October.
Ammonium nitrate was used to supply nitrogen.
Potash (potassium chloride) was applied
monthly at 0.50 pound potasssium/1,000
square feet, and phosphorus from super-phosphate
was applied at 0.50 pound/1,000 square
feet (24.4 kilograms/hectare) every other
month. Each mowing height and fertilizer
combination was replicated four times. Plots
were mowed six times weekly. Turf was not
overseeded between years, as this would interfere
with nitrogen uptake and seasonal
responses to fertility and mowing.
Turf responses
When possible, we made standard
monthly NTEP visual evaluations of color
and quality. Ball roll distance was measured
monthly by recording three ball rolls in each
of two directions from a USGA Stimpmeter
immediately after daily mowing and again following
an additional rolling of the green.
Rolling was not a regular maintenance practice
but was done only on the day of ball roll
distance measurements.
Results and discussion
Turfgrass color: <strong>2000</strong> and 2001
<strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> produced a light- to
medium-green turf. Color ratings increased
with increasing mowing height (Table 1). The
increases were significant on seven of 11 rat-
Photo courtesy of Dave Kopec
84 GCM
November 2005

ing dates, but this trend was consistent on
almost every evaluation date. In both <strong>2000</strong>
and 2001, turf color responded positively to
fertilization rate, with improved color at the
higher levels of nitrogen fertilization. In general,
turf color was lightest in July (monsoon
period), averaging less than 6.0 in both years.
Turf color scores were noticeably higher in
October 2001 than in October <strong>2000</strong>, probably
because temperatures in fall 2001 were
unseasonably warm.
To maintain a color score of 6.0 or greater
throughout the test, turf mowed at 1 ⁄8 inch
required 0.50 pound nitrogen/1,000 square
feet/month; turf mowed at 5 ⁄32 required 0.38
pound, and turf mowed at 3 ⁄16 inch required
0.25 pound.
TURF COLOR, <strong>2000</strong> & 2001
Turf quality: <strong>2000</strong> and 2001
Mowing height had no consistent or
significant influence on visual quality, and
turfgrass quality was not influenced by the
combination of applied nitrogen fertilizer and
mowing height (Table 2).
Turf responses to fertilizer were different
each year. In <strong>2000</strong>, turfgrass quality declined
as nitrogen rate increased early in the season
(June). This showed that <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> performed
just as well or slightly better when it
received low rates of nitrogen (0.25 and 0.38
pound/nitrogen/1,000 square feet/month).
In general, in turf that was not overseeded,
medium to high rates of nitrogen (0.50
pound/1,000 square feet/month) improved
turf quality in the spring and fall, and low rates
of nitrogen (0.25-0.38 pound/1,000 square
feet/month) provided good turf quality during
the hottest months of summer. Across both
years, turf mowed at 1 ⁄8 inch required 0.50
pound nitrogen/1,000 square feet/growing
month to produce a turf quality score of 6.0
or greater, and turf mowed at 5 ⁄32 and 3 ⁄16 inch
produced turf quality ratings of 6.0 or higher
when fertilized with only 0.25 pound nitrogen/1,000
square feet/growing month. When
not overseeded, seashore paspalum is fully
green from May to October in the desert.
Leaf widths
Leaf widths were measured in August
2001. Twelve shoots were sampled from each
plot, and leaf width was measured to the nearest
0.1 millimeter. Leaf width showed little
variation across all plots (1.4-1.7 millimeters
for the second leaf, and 1.4-1.8 millimeters
for the third leaf). Neither mowing height nor
RESEARCH
nitrogen fertilization rates produced profound
effects for leaf texture or leaf width measurements
in <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong>.
Ball roll distance: <strong>2000</strong>
In <strong>2000</strong>, ball roll distance was measured
on six calendar dates. On three of these dates,
the greens were rolled, and ball roll distance
was measured immediately after rolling. In
<strong>2000</strong>, mowing height significantly affected
ball roll distance in seven of eight measurements
(Table 3). When averaged over all
nitrogen rates, mean ball roll distance values
ranged from 4 feet, 10.4 inches ( 3 ⁄16 inch
mowing height, July 13) to 7 feet, 10.1 inches
( 1 ⁄8 inch mowing height, Oct. 31).
In <strong>2000</strong> turf mowed at 1 ⁄8 inch ranked first
for ball roll distance on four dates (July 13,
July 28, Aug. 31 and Oct. 31) when it was
mowed and not rolled and ranked first for ball
roll distance on two dates when it was mowed
and also rolled (Aug. 31, Nov. 7). When turf
was mowed without rolling, turf mowed at 5 ⁄32
inch had greater ball roll distances than turf
mowed at 3 ⁄16 inch in July and August but not
in September and October.
In general, increases in ball roll distance
were linearly related to a decrease in mowing
Mowing height (inches)
<strong>2000</strong> ratings 2001 ratings Average,
<strong>2000</strong> &
June 27 July 28 Aug. 28 Sept. 27 Oct. 30 May 17 June 25 July 23 Aug. 21 Sept. 10 Oct. 6 2001
1
⁄8 6.3 5.2 6.3 6.3 5.7 6.5 6.1 5.6 6.6 5.8 6.3 6.0
5
⁄32 6.1 6.3 6.1 6.9 6.3 7.3 6.8 5.8 6.5 6.3 6.8 6.4
3
⁄16 6.0 6.1 6.8 6.6 5.7 7.3 6.8 5.8 7.3 6.8 7.0 6.5
Test mean 6.1 5.9 6.4 6.6 5.9 7.0 6.6 5.7 6.8 6.3 6.7 6.3
LSD ns 0.44 ns ns 0.50 0.68 0.65 ns 0.60 0.87 0.60
Fertilizer rate (pounds/nitrogen/1,000 square feet)
0.25 5.8 5.4 5.8 6.0 5.3 6.1 6.4 5.4 6.3 5.9 6.0 5.9
0.38 5.8 5.7 6.3 6.0 5.4 6.8 6.1 5.8 6.7 6.3 6.3 6.1
0.50 6.1 6.2 6.4 6.8 5.9 7.3 6.8 5.9 6.9 6.2 6.8 6.5
0.75 6.8 6.1 6.9 7.6 6.8 7.9 7.0 5.8 7.3 6.9 7.7 6.9
Test mean 6.1 5.9 6.4 6.6 5.9 7.0 6.6 5.7 6.8 6.3 6.7 6.4
LSD 0.80 ns 0.81 0.40 0.67 0.51 ns ns 0.38 0.69 0.57
Note. Color was rated on a scale of 1-9, where 1 = dead, 6= fully acceptable and 9 = best possible. Values are the mean of four replications. Test mean = mean of all treatments
on that date. LSD = Least significant difference mean separation statistic. ns, not significant.
Table 1. Visual color of a <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> paspalum putting green under selected mowing height and fertilization regimes, summer <strong>2000</strong> and 2001, Karsten Turfgrass Research
Facility, University of Arizona.
November 2005
GCM 85

RESEARCH
VISUAL QUALITY
height on all dates, whether turf was only
mowed or mowed and then rolled (Figure 2).
Interestingly, in September and October, turf
at 3 ⁄16 inch that was double-mowed and also
rolled once produced a greater ball roll distance
(7 feet, 4.1 inches) than the 5 ⁄32 inch turf
that was not rolled (6 feet, 9.5 inches).
Because nitrogen fertilizer rate generally
had little effect on ball roll distance, those data
are not included. Nitrogen fertilizer rate was
2001 ratings Average, <strong>2000</strong>
May 17 June 25 July 23 Aug. 21 Sept. 10 Oct. 6 & 2001
Mowing height (inches)
1
⁄8 6.0 6.5 6.3 7.3 6.9 6.7 6.5
5
⁄32 7.2 7.1 6.4 6.8 7.1 6.8 6.9
3
⁄16 6.7 6.8 6.8 6.9 6.8 6.8 6.8
Test mean 6.6 6.8 6.5 7.0 6.9 6.7 6.8
LSD ns ns ns ns ns ns
Fertilizer rate (pounds nitrogen/1,000 square feet)
0.25 6.2 6.3 6.4 7.4 7.6 7.7 6.8
0.38 6.3 6.8 6.3 7.0 6.9 6.8 6.7
0.50 6.8 6.8 6.8 7.0 6.7 6.4 6.8
0.75 7.1 7.3 6.3 6.4 6.7 6.0 6.7
Test mean 6.6 6.8 6.5 7.0 6.9 6.7 6.7
LSD 0.80 0.92 ns 0.66 0.73 0.51
Note. Quality is rated on a scale of 1-9, where 1 = dead, 6 = fully acceptable and 9 = best possible. Values are
the mean of four replications. Test mean = mean of all treatments on that date. LSD, least significant difference.
ns, not significant.
Table 2. Visual turf quality of <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> seashore papsalum under select mowing heights and nitrogen fertilization,
summer 2001, and average of summer <strong>2000</strong> and summer 2001, Karsten Turfgrass Research Facility,
University of Arizona.
significant statistically for two of eight ball roll
distance measurements, both of which did not
involve rolling the green.
In general, the low rate of fertilizer (0.25
pound nitrogen/1,000 square feet/month)
increased ball roll distances by 2-4 inches over
all other rates of applied nitrogen. Although
this is statistically significant, it is not important
in terms of turfgrass management.
Ball roll distance: 2001
In 2001, ball roll distance was measured
12 times (six with rolling and six without
rolling each month for six months).
Decreasing mowing height increased ball roll
distance, whether or not the turf received supplemental
rolling. In general, rolling 1 ⁄8-inch
turf added about 6 inches to ball roll distance
in May and June compared to identical plots
that were mowed and not rolled. This was not
true in mid-summer, when rolling decreased
ball roll distance by 3-4 inches. As in <strong>2000</strong>,
nitrogen fertility rate had no statistical or biological
effect on ball roll distance.
For all measuring dates, ball roll distance
decreased as mowing height increased in both
rolled and unrolled turf. In general, the greatest
difference in ball roll distance occurred
between the 5 ⁄32-inch and 3 ⁄16-inch mowing
heights. Ball roll distance was generally longer
and more consistent in 2001 than in <strong>2000</strong>.
Ball roll distance was greatest in June and
BALL ROLL, <strong>2000</strong> & 2001
<strong>2000</strong> ball roll distance (feet, inches)
Mowing height July 13 July 28 Aug. 31 Sept. 26 Oct. 31 Nov. 7
1
⁄8 inch 5, 10.1 6, 1.2 6, 8.3 7, 3.8 7, 3.0 7, 4.1 7, 10.1 8, 9.8
5
⁄32 inch 5, 6.8 5, 11.7 6, 4.3 6, 8.8 6, 9.5 6, 11.9 7, 2.5 7, 10.4
3
⁄16 inch 4, 10.4 4, 11.6 5, 8.3 6, 4.5 7, 3.9 7, 4.1 7, 6.5 8, 2.2
Test mean 5, 5.1 5, 8.1 6, 3.0 6, 9.7 7, 1.5 7, 2.7 7, 6.4 8, 3.5
LSD 1.4 4.6 2.1 4.2 6.1 3.1 ns 3.6
2001 ball roll distance (feet, inches)
Mowing height May 22 June 27 July 20 Aug. 21 Aug. 23 Sept. 26 Oct. 10
1
⁄8 inch 6, 6.9 7, 0.9 8, 4.4 8, 11.9 7, 5.4 7, 8.4 7, 2.8 7, 0.8 6, 10.2 7, 1.3 7, 2.0 8, 4.7
5
⁄32 inch 6, 1.0 6, 3.7 6, 0.2 6, 4.3 6, 2.3 6, 2.3 6, 9.8 6, 8.5 6, 4.9 6, 8.0 6, 7.8 6, 11.0
3
⁄16 inch 5, 8.6 5, 10.4 5, 4.9 5, 10.7 5, 7.4 5,9.4 6, 0.7 5, 10.5 5, 10.8 5, 11.2 6, 0.1 6, 3.9
Test mean 6, 1.5 6, 5.0 6, 7.2 7, 0.9 6, 5.1 6, 6.7 6, 8.4 6, 6.6 6, 4.6 6, 6.8 6, 7.3 6, 11.2
LSD 2.3 1.8 5.2 8.1 3.6 2.3 3.3 5.4 5.2 3.6 4.1 5.0
Table 3. Ball roll (three rolls east to west, and three rolls west to east), in inches, from a <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> green in summer <strong>2000</strong> and 2001, Karsten Turfgrass Research Facility,
University of Arizona. Values in light green columns are measurements from rolled green treatment.
86 GCM
November 2005

second-highest in July. Rolling increased ball
roll distance across all mowing heights and
nitrogen fertilizer treatments. Rolling provided
the greatest benefit in May and
October, which are periods of slower growth
for warm-season grass.
A single rolling increased ball roll distance
by 6 inches for turf mowed at 1 ⁄8 inch in May,
June and July, with only a 3- to 4-inch
increase in September and October 2001. It
is argued that golfers cannot notice ball roll
distance increases of less than 10 inches, in
which case, rolling would be insignificant as
a tournament tool. However, some form of
regular rolling may be necessary to obtain and
maintain acceptable ball roll distance values in
seashore paspalum in a desert climate.
Ball roll distance: <strong>2000</strong> and 2001
Mowing height had a greater effect on ball
speed than applied nitrogen fertilizer rates in
both years. The rates of applied nitrogen rates
included in this test had minimal affect on
ball roll distance.
Rolling increased ball roll distance more in
<strong>2000</strong> than in 2001, but summer ball roll distances
were greater overall in 2001. The greatest
ball roll distance — 8 feet, 11.9 inches —
was measured in June 2001. In general, ball
roll distance on turf mowed at 1 ⁄8 inch was 10
to 22 inches greater than on turf mowed at 3 ⁄16
inch. Rolling added anywhere from 4 to 12
BALL ROLL DISTANCE
Ball roll distance
100
90
80
70
60
50
40
30
20
10
0
THE RESEARCH says . . .
Figure 2. Ball roll distance of <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> Paspalum was measured and averaged over two years at three
mowing heights.
RESEARCH
➤ <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> tolerated mowing at 1 ⁄8 inch for two years in a desert climate when mowed six
times weekly with a Toro Series 5 Tournament Mower using a grooved front roller.
➤ <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> ranged from light to light-medium green in color, depending on mowing height
and fertilization. In general, the inherent color of <strong>Sea</strong> <strong>Isle</strong> <strong>2000</strong> paspalum is lighter than
Tifgreen 328 bermudagrass (long-term observations).
➤ In general, it was possible to maintain turfgrass quality of 6.0 or greater at the following
mowing heights and pounds of applied nitrogen/1,000 square feet: 1 ⁄8 inch and 0.50 pound;
5
⁄32 inch and 0.38 pound; 3 ⁄16 inch and 0.25 pound.
➤ Ball roll distance was affected more by mowing height than by nitrogen fertilization rates.
➤ The differences between treatments for ball roll distances were anywhere from 20-40
inches within a given year.
➤ The greatest ball roll distance was 8 feet, 11.9 inches in July 2001 on turf mowed at
1
⁄8 inch, which would be considered suitable for tournament play.
inches to ball roll distance. In this study, rolling
took place only once a month and only on the
day that ball roll distance was measured.
USGA standards classify a ball roll distance
of 8 feet, 4 inches as medium (just short of fast)
for regular membership play. However, most ball
roll distances in turf mowed at 1 ⁄8 inch averaged
about 7 feet, 3 inches, which would qualify as
medium in regular play. Under the management
conditions of this test (vertical mowing and topdressing
every 14 days), all other ball roll distance
values obtained at mowing heights of 5 ⁄32 and 3 ⁄16
inch would be considered marginal. Within each
mowing height, fertility did not appreciably
affect ball roll distance.
■ 1 ⁄8 inch ■ 5 ⁄32 inch ■ 3 ⁄16 inch
Rolled
Not rolled
Acknowledgments
We thank The Environmental Institute for Golf,
Cactus and Pine GCSA, USGA and The Toro Co. for helping
to fund this research.
References
1. Beard, J.B., S.I. Sifers and M.H. Hall. 1991a. Cutting
height and nitrogen fertility requirements of Adalayd
seashore paspalum (Paspalum vaginatum). Texas
Turfgrass Research PR-4921:107-109.
2. Beard, J.B., S.I. Sifers and W.G. Menn. 1991b.
Cultural strategies for seashore paspalum. Grounds
Maintenance 8:32, 62.
3. Huang, B., R.R. Duncan and R.N. Carrow. 1997a.
Drought resistance mechanisms of seven warmseason
turfgrasses under surface soil drying. I. Shoot
response. Crop Science 37(6):1858-1863.
4. Huang, B., R.R. Duncan and R.N. Carrow. 1997b.
Drought resistance mechanisms of seven warmseason
turfgrasses under surface soil drying. II. Root
aspects. Crop Science 37(6):1863-1866.
5. Marcum, K.B., and C.L. Murdoch. 1994. Salinity tolerance
mechanisms of six C4 turfgrasses. Journal of
the American Society of Horticultural Science
119(4):779-784.
6. Sigua, G.C., and W.H. Hudnaill. 1992. Nitrogen and
gypsum: Management tools for revegetation and
productivity improvement of a brackish marsh in
southwest Louisiana. Communications in Soil
Science and Plant Analysis 23(3&4):283-299.
7. Trenholm, L.E., R.N. Carrow and R.R. Duncan. 2001.
Wear tolerance, growth, and quality of seashore paspalum
in response to nitrogen and potassium.
HortScience 36(4):780-783.
8. USGA. 1996. Stimpmeter instruction booklet. USGA,
Far Hills, N.J. www.usga.org/turf/articles/management/
greens/stimpmeter.html. Verified Sept. 13, 2005.
David M. Kopec is an Extension specialist in turfgrass,
Jeffrey J. Gilbert is a senior research specialist, and
Mohammad Pessarakli is a research faculty member and
lecturer in the plant science department at the University of
Arizona, Tucson. James H. Walworth is an Extension specialist
in soil fertility and Greg M. Sower is a former
research technician in the soil, water and environmental
sciences department at the University of Arizona, Tucson.
November 2005
GCM 87