Klamath Experiment Station
Pasture and Hay Grass Variety Trial, 1997
R.L. Dovel and J. Rainey'
A
bstract
A 24 entry pasture grass trial, including 6
species, was planted in the fall of 1995 at
Klamath Experiment Station (KES). Plots were
arranged in a randomized split-plot design with 3
replications. Clipping management was the main
plot and variety was the split-plot. Forage was
allowed to grow unclipped in the establishment
year. Plots managed as a hay trial were cut to 2inch height when 50 percent of the entries were
heading. Plots being managed as simulated grazed
plots were cut to a 4-inch height when 50 percent
of the entries reached 10 inches or more in height.
Clipping management was the most significant
factor affecting forage yield. Simulated grazing
produced only 53 and 49 percent as much dry
matter as hay management in 1996 and 1997,
respectively. In 1996, Matua was the highest
yielding entry under both hay and simulated
grazing management. The next three highest
yielding entries under hay management in 1996
were tall fescue entries, ISI-9077, ISI-8872, and
AU Triumph. Kemal, a Festulolium, was not
significantly lower yielding than the three highest
yielding tall fescues in the first year of the trial. In
1997, yields of Matua, Gala, Kemal, and all three
perennial ryegrass varieties declined to roughly
one-half of 1996 levels under both clipping
systems. ISI-9077, ISI-8872, and AU Triumph
produced significantly higher yields than all other
tall fescue entries in 1996. However, there were
no significant differences among tall fescue entries
in 1997. Lupre, Tekapo, and Comet were the
highest producing orchardgrass entries in 1996
under hay management. Of these three entries,
only Comet maintained high levels of production
in 1997, yielding 99 percent of 1996 levels.
Average protein and TDN content were 16.8 and
59.0 percent under clipping management compared to 22.2 and 64.2 percent under simulated
grazing. All entries had high forage quality, with
minimum values of 14.0 percent protein and 53.6
percent TDN, under hay management. Matua
produced the lowest protein concentration under
grazing. Matua and Gala produced the lowest
TDN value under grazing. Average forage TDN
values for tall fescue were similar to perennial
ryegrass and orchardgrass under both hay and
simulated grazing management. Barcel tall fescue
had the highest forage quality of all tall fescue
varieties, averaging 59.4 and 65.4 percent TDN
under hay and simulated grazing clipping management, respectively. Average forage protein of
orchardgrass was slightly higher than perennial
ryegrass and tall fescue, under hay management.
There was no difference in protein content among
the three main species under grazing management.
Introduction
Several grass hay variety trials were
established at Klamath Experiment Station in
1988. Since that time, new varieties have been
developed and should be tested in this area. In
addition, there is a need to test pasture grasses
under a management system that more accurately
reflects controlled grazing and not a three cutting
hay schedule. A trial was established to test
forage production and stand persistence of
'/Associate Professor, and Biological Sciences Research Technician III, respectively, Klamath Experiment
Station, Klamath Falls, OR.
Klamath Experiment Station 1997 145
Klamath Experiment Station
Pasture and Hay Grass Variety Trial, 1997
pasture grasses in the Klamath Basin under
both haying and simulated grazing management. Entries included released and soon-tobe released varieties of tall fescue, orchardgrass, perennial ryegrass, andBromus
species.
Procedures
The trial was planted in the fall of
1995 at KES. Plots were arranged in a
randomized split-plot design with 3 replications. Clipping management was the main plot
and variety was the split-plot. Seed was sown
in 6-inch rows using a cone seeder. Seeding
rate was as recommended for each species
(Table 1). Planting depth was 0.25 inches.
Plots were 5 x 20 feet with 5-foot wide
alleyways.
Prior to seeding, fertilizer was applied
and incorporated as indicated by soil tests.
Nitrogen was applied at 75 lb N/acre at
planting. Following establishment, 50 lb N/
acre was applied in mid-March, mid-June,
and mid-July. Plots were irrigated with solidset sprinklers. Evapotranspiration was deter
mined from a weather station on site, and
weekly applications were made accordingly.
Forage was allowed to grow
unclipped in the establishment year. Plots
managed as a hay trial were cut when 50
percent of the entries were heading. Cutting
height in these plots was 2 inches. Plots being
managed as simulated grazed plots were cut
when 50 percent of the entries reached 10
inches or more in height. Simulated grazing
plots were cut to a 4-inch cutting height. Plots
were clipped using a Carter flail plot harvester. Measurements will be taken for three
146 Klamath Experiment Station 1997
full production years. Winter survival will be determined for three winter periods.
All yields are reported on a dry weight basis.
Forage quality, as determined by crude protein (CP),
acid detergent fiber (ADF), neutral detergent fiber
(NDF), total digestible nutrients (MN), and relative
feed value (RFV), was evaluated from samples
obtained at all harvests.
Results
Yield
Clipping management was the most significant
factor affecting forage yield. Simulated grazing
produced only 53 and 49 percent as much dry matter
as hay management in 1996 and 1997, respectively
(Table 1). Frequent clipping reduces photosynthetic
surface area and thus reduces growth. The longer
clipping interval of the hay clipping treatment allowed
a much larger photosynthetic area to produce growth.
Average hay yield dropped from 12,520 lb/acre in
1996 to 9,320 in 1997, a 26 percent decline. Average 1997 pasture yield dropped to 69 percent of
1996 levels. Relative yield among entries changed
from 1996 to 1997. In 1996, Matua was the highest
yielding entry under both hay and simulated grazing
management. The next three highest yielding entries
under hay management in 1996 were tall fescue
entries, ISI-9077, ISI-8872, and AU Triumph.
Kemal, a Festulolium, was not significantly lower
yielding than the three highest yielding tall fescues in
the first year of the trial. In 1997, yields of Matua,
Gala, Kemal, and all three perennial ryegrass varieties
declined to roughly one-half of 1996 levels under
both clipping systems.
Tall fescue was the highest producing species
in 1997 due to dramatic declines in production of
Matua, Gala, and Kemal. Of the three most widely
planted species (orchardgrass, perennial ryegrass,
Klamath Experiment Station
Pasture and Hay Grass Variety Trial, 1997
and tall fescue), tall fescue was the highest
producing. Orchardgrass produced approximately 1 ton/acre less than tall fescue in both
1996 and 1997. Perennial ryegrass produced
similar yields to orchardgrass in 1996, but significantly lower yields than orchardgrass in 1997.
ISI-9077, ISI-8872, and AU Triumph
produced significantly higher yields than all other
tall fescue entries in 1996. However, there were
no significant differences among tall fescue entries
in 1997. Barcel and Fuego were lower producing
than other tall fescue varieties in 1996, but not
different in 1997. Barcel is noted to be slow
establishing. Low yields of Fuego in 1996 resulted from poor establishment, presumably due
to low viability of the seed lot received for the
trial. Fuego plots were overseeded in 1996 with
seed from another source and plant density
increased to acceptable levels.
Lupre, Tekapo, and Comet were the
highest producing orchardgrass entries in 1996
under hay management. Of these three entries,
only Comet maintained high levels of production
in 1997, yielding 99 percent of 1996 levels. Other
orchardgrass entries that maintained hay yields of
90 percent or better of 1996 yields include
Bronc, BAR H DGL 051, Potomac, and
Cambria. Frequent defoliation under the simulated
pasture clipping regime reduced second year
production of orchardgrass more than hay
clipping management. Only BAR H DGL 051
maintained production levels above 90 percent of
1996 levels under simulated grazing management.
Forage Quality
Forage quality trends were similar across
years and are reported in Table 2 and discussed
below as two-year means. As was seen in forage
yield, clipping management was the most significant factor affecting forage quality, both protein
and TDN. Average percent protein and '1'1)N
were 16.8 and 59.0 under clipping management
compared to 22.2 and 64.2 under simulated
grazing. All entries had high forage quality, with
minimum values of 14.0 percent protein and 53.6
percent TDN, under hay management. Matua
produced the lowest protein concentration under
grazing. The low protein of Matua is due to high
biomass production. Nitrogen uptake and assimilation did not keep up with the rate of forage
production. Matua and Gala produced the lowest
TDN value under grazing. Mama produced more
rapid regrowth than most other entries in the trial
and the resulting older biomass may have resulted
in lower digestibility. Gala TDN values are
probably low due to low genetic potential. It was
not selected for high forage quality and has been
criticized by other researchers for low digestibility.
Average forage TDN values for tall
fescue were similar to perennial ryegrass and
orchardgrass under both hay and simulated
grazing management. This was unexpected.
Perennial ryegrass is reputed to have higher
forage quality than other cool-season pasture
grasses, and tall fescue is thought to have lower
forage quality than either orchardgrass or perennial ryegrass. Under hay management, lower
perennial ryegrass TDN values may be explained
by different maturity levels of the species involved. Perennial ryegrass varieties evaluated in
this study tend to be earlier maturing than orchardgrass and tall fescue varieties included in this
trial. However, clipping frequency under simulated
grazing management was approximately two
weeks and differences in maturity would be
negligible.
Klamath Experiment Station 1997 147
Klamath Experiment Station
Pasture and Hay Grass Variety Trial, 1997
Average forage protein of orchardgrass
was slightly higher than perennial ryegrass and tall
fescue, under hay management. There was no
difference in protein among the three main species
under grazing management.
There was also considerable variability in
forage quality within species. The most notable
example of this is Barcel tall fescue, which has
been selected for high quality. It had an average
TDN of 59.4 and 65.4 under hay and simulated
grazing clipping management, respectively.
Seasonal Trends
Because the clipping frequency of the
simulated grazing treatment was approximately
every two weeks, seasonal trends in forage
growth and quality can be examined. Growth rate
is calculated by dividing the dry matter produced
by the number of days in the growth period.
Trends for the two years were similar but relative
levels differed. Data for both years are included in
Figure 1. Growth rate was initially slow in the
spring due to cool temperatures. It rose to
maximum levels by late June and remained high
through mid-July before dropping to one-half the
maximum level during late July and early August.
This was due to temperatures exceeding optimal
levels for cool-season grass growth in late summer. As temperatures cooled in late August,
growth rates recovered to former levels. Growth
rates declined in late September as temperatures
cooled.
Cool-season grass growth responses to
temperature may be examined by comparing
growth rates during a growth period to the
average temperature during that period. The
relationship of growth rate and temperature can
be detei mined using regression analysis. This
148 Klamath Experiment Station 1997
relationship is depicted in Figure 2. Growth rate
approached zero as temperatures dropped below
52 °F and rose until reaching an optimal temperature of about 65 °F. As average temperatures
rose above 65 °F, growth rates declined. Using
this correlation, it is easy to understand the
phenomena known as the summer slump, when
cool-season grass growth declines even when
moisture is not limiting.
Species response to temperature differed.
Orchardgrass was more sensitive to cool temperatures than perennial ryegrass and tall fescue
(Figure 3). The growth rate curve of perennial
ryegrass was lower than the other two main
species in the trial and much flatter, reflecting the
lower yield potential of this species in the Klamath
Basin. Both tall fescue and orchardgrass growth
rates declined as mean daily temperatures rose
above 65 °F, but tall fescue was more adversely
affected by high temperatures than orchardgrass.
Growth rates of all species in the trial, except
Matua, declined when mean daily temperatures
rose above 65 °F (Figures 3 and 4). Matua
growth rates continued to increase slightly as
temperature increased even during the hottest
period of the summer (Figure 4). This species
holds promise as a forage resource during the
summer slump.
Forage quality also varied across the
season. Protein concentration of simulated grazed
plots varied widely from cutting to cutting. Trends
for the two years were similar, but relative levels
differed. Data for both years are included in
Figure 5. Initially there appeared to be no pattern,
however, N fertilization dates must also be
considered. Plots were fertilized immediately after
each hay cutting, which are depicted in Figure 5
as light squares. Immediately after fertilization,
Klamath Experiment Station
Pasture and Hay Grass Variety Trial, 1997
forage protein concentration rose and then
declined steadily until fertilizer was applied again.
Multiple N applications will result in more uniform
protein levels throughout the season than a single
large application in the spring.
Seasonal trends were also observed in
TDN levels, and were largely correlated with
temperature and not N fertilization (Figure 6).
1DN levels declined as temperatures increased in
the spring until reaching a low in early August.
They then returned to the high levels seen in the
spring as temperatures cooled in the fall.
TDN was highly correlated with temperature. A simple linear relationship adequately
described the effect of temperature on TDN.
Regression equations were developed for most of
the entries in the trial and are depicted in Figure 7.
There is little difference in the slope of the lines,
which indicates that the entries respond similarly
to temperature. There is a large group of entries in
the middle with little difference between them, and
three clearly distinct entries. The two entries with
high TDN are BG3 and Barcel and the low TDN
entry is Matua. This is similar to the tabular data
using season-long averages in Table 2.
Klamath Experiment Station 1997 149
Klamath Experiment Station
Table 1. Effect of clipping management on total forage yield of cool-season grasses established at KES,
Klamath Falls, OR, 1995, harvested 1996 and 1997. Values represent totals from three and eight harvests
for hay and simulated grazing, respectively.
Variety
Species
Hay yield
1996
1997
Percent
of 1996
lb/A
Pasture yield
1996
1997
Percent
of 1996
Percent of hay
1996
1997
- lb/A ---
%
Gala
BS
13,930
7,420
53
8,280
3,060
37
59
41
Matua
BW
19,450
8,440
43
11,480
3,880
34
59
46
Kemal
FES
14,880
6,280
42
6,570
3,300
50
44
53
BAR H DGL 051
BAR H DGL SUSF
Bronc
Cambria
Comet
Latar
Lupre
Pizza
Potomac
Tekapo
Mean OG
OG
OG
OG
OG
OG
OG
OG
OG
OG
OG
10,720
10,990
10,950
10,470
11,240
10,570
11,640
10.880
10,790
11.290
10,950
10,060
9,620
10,640
9,400
11,160
8,900
8,760
8,960
9,960
8,980
9,640
94
88
97
90
99
84
75
82
92
80
88
6,470
5,370
6,440
4,490
6,040
6,310
6,580
6,080
6,190
5,920
5,990
6,260
4,740
4,880
3,680
5,360
4,960
4,500
4,360
5,140
3,700
4,760
97
88
76
82
89
79
68
72
83
63
79
60
49
59
43
54
60
57
56
57
52
55
62
49
46
39
48
56
51
49
52
41
49
BG3
Moy
Zero-nui
Mean PRG
PRG
PRG
PRG
11,630
10,960
11.660
11,420
4,320
6,320
5,240
5,290
37
58
45
46
5,040
6,010
6,060
5,700
1,700
2,660
2,620
2,330
34
44
43
41
43
55
52
50
39
42
50
44
TF
TF
TF
TF
TF
TF
TF
TF
15,110
12,370
13,820
13,820
14,190
8,630
15,230
15,320
13,560
11,180
11,620
10,660
11,000
12,200
10,740
10,840
11,020
11,160
74
94
77
80
86
124
71
72
82
9,080
5,400
6,630
7,620
6,670
3,530
8,060
6,880
6,730
5,360
4,280
5,220
5,080
6,360
5,560
6,320
5,780
5,500
59
79
79
67
95
158
78
84
82
60
44
48
55
47
41
53
45
50
48
37
49
46
52
52
58
52
49
12,520
570
14
9,320
1,640
10
74
6,550
180
38
4,530
750
10
69
52
49
AU Triumph
Barcel
Desperado
Do\'ey
Fawn
Fuego
ISI-8872
ISI-9077
Mean TF
Mean
LSD (P = 0.05)
CV (%)
150 Klamath Experiment Station 1997
Klamath Experiment Station
Table 2. Effect of clipping management on average forage quality of cool-season grasses established at
KES, Klamath Falls, OR, August 1995, harvested in 1996 and 1997.
Variety
Species'
'1DN
hay
grazed
Protein
hay
grazed
%
Gala
BS
16.5
22.7
55.0
61.6
Matua
BW
14.2
27.1
55.0
61.6
Kemal
FES
15.4
21.1
57.8
64.3
BAR 051
BAR 5USF
Bronc
Cambria
Comet
Latar
Lupre
Pizza
Potomac
Tekapo
Mean OG
OG
OG
OG
OG
OG
OG
OG
OG
OG
OG
15.4
15.2
15.8
16.4
15.9
15.7
15.5
15.5
15.5
15.7
15.7
21.7
21.8
22.2
22.4
21.8
22.4
22.6
22.7
22.1
21.8
22.2
56.3
57.1
58.1
57.2
58.3
57.6
55.9
57.7
56.9
55.9
57.1
63.0
64.4
64.8
64.8
64.2
63.9
64.5
64.4
64.5
63.6
64.2
BG3
Moy
Zero-nui
Mean PRG
PRG
PRG
PRG
16.3
15.7
15.2
15.7
22.0
20.7
20.7
21.1
60.0
58.0
57.2
58.4
65.5
63.8
63.6
64.3
TF
TF
11TF
TF
TF
TF
TF
15.7
16.6
15.4
14.8
15.4
20.8
21.4
20.7
19.9
21.2
58.9
59.4
58.8
57.3
57.6
63.3
65.4
64.2
62.2
63.8
15.4
15.4
15.6
20.8
20.1
20.9
58.0
58.0
58.5
63.7
63.0
63.9
15.6
0.6
12
21.5
0.9
7
57.6
0.7
2.0
63.9
1.4
3
AU Triumph
Barcel
Desperado
Dovey
Fawn
Fuego
ISI-8872
ISI-9077
Mean TF
Mean
LSD (P= 0.05)
CV (%)
1
1Bromus stamineus (BS), B. willdenowii, (BW), festulolium (meadow fescue x
annual ryegrass), orchardgrass (OG), perennial ryegrass (PRG), and tall fescue (TG).
Klamath Experiment Station 1997 151
Klamath Experiment Station
— 1996 - - -1997
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Experiment Station in 1996 and 1997.
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Figure 2. Mean daily temperature effect on growth rate (lb dry matter/acre/day of cool-season grasses
grown at Klamath Experiment Station in 1996 and 1997.
152 Klamath Experiment Station 1997
Klamath Experiment Station
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Figure 4. Mean daily temperature effect on growth rate (lb dry matter/acre/day) of Kemal Festulolium,
Matua prairiegrass, and Gala grazing brome grown at Klamath Experiment Station in 1996 and 1997.
Klamath Experiment Station 1997 153
Klamath Experiment Station
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Klamath Experiment Station 1997
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Klamath Experiment Station
AU Triumph
70
Latar
—A—Cambria
—x— Zero-nui
68
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M oy
Potomac
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Fawn
BG3
- - - - Comet
- - - - Kemal
- - *- - Matua
z6
- - x - - Gala
62
x
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- - - - Lupre
- - - - Barcel
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- - * - - ISI-9077
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70
- - o - - ISI-8872
- - - BAR H DGL 051
--s— BAR H DGL 5USF
MEAN DAILY TEMPERATURE - - 0 - -Tekapo
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Figure 7. Mean daily temperature and variety effects on forage TDN (total digestible nutrients)
concentration of cool-season grasses grown at Klamath Experiment Station in 1996 and 1997.
Klamath Experiment Station 1997 155