Evaluation of Warm-Season Perennial Grasses

Transcription

Evaluation of Warm-Season Perennial Grasses
Evaluation of Warm-Season
Perennial Grasses
NF-FO-06-02
by James Rogers / [email protected]
Introduction
Introduced and native warm-season
perennial grasses cover 21.7 million
acres in Oklahoma. Perennial forages
have an advantage over annual forages because they do not have to be
re-established annually, provided they
can persist over time. Differences can
exist between warm-season perennial species in their persistence, yield,
yield distribution and quality. The
purpose of this study is to evaluate
these differences and provide producers with decision aids in the selection
of warm-season perennial grasses.
Thirteen of the 14 entries in the evaluation originally were established in
1998. From 1998 to 2003, little to no
management was applied to the plots
and little data was collected. In 2003,
the plots were renovated, and a production and management protocol
was developed. Data presented in this
publication is a result of that protocol.
In spring 2004, Sand Mountain bahiagrass was added to the evaluation.
Descriptions of Species and Varieties
Included in the Evaluation
Alamo switchgrass
This is a lowland variety of switchgrass (Panicum virgatum) that is
typically 1 to 3 feet taller than upland
switchgrass strains at maturity. In
comparison to upland strains, it
grows more rapidly and is longer
leafed and somewhat coarser. Plants
tend to be bunch type and weakly
rhizomatous. It is best adapted to
silty or clayey soils, but can also be
found growing on sandy soils. As a
lowland variety, it is best adapted
to areas with adequate moisture. It
can tolerate a wide range of soil pH.
Established from seed in the spring,
Alamo switchgrass is known for its
high forage production and difficulty
in management for quality grazing.
Switchgrass
Blackwell switchgrass
Blackwell switchgrass is an upland
variety of switchgrass (Panicum virgatum) that has good drought tolerance
and is strongly rhizomatous. It is not
as productive as Alamo, but is more
drought tolerant. It tolerates a wide
range of soil pH and types. Its foliage
is finer than that of Alamo. Switchgrass is established from seed in the
spring.
Selection 75 kleingrass
Kleingrass (Panicum coloratum) is an
introduced forage from Africa. Selection 75 is an improved variety released
from Texas in 1968. It grows to 3 to 4
feet at maturity, and its stems tend
to be somewhat fine with numerous
leaves. It is spread by tillers, seed and
rhizomes, though it is established
from seed in the spring. It will grow on
sandy to clay type soils and tends to
have good drought resistance, but its
cold tolerance has been questioned. It
can cause photosensitization in sheep
and hepatoxicosis in horses.
Samuel Roberts Noble Foundation
Midland 99 bermudagrass
Midland 99 was released as a variety
in 1999 by The Samuel Roberts Noble
Foundation, Inc., USDA-ARS Grazinglands Research Laboratory and the
Arkansas, Kansas and Missouri Agricultural Experiment Stations. This bermudagrass (Cynodon dactylon) was
developed for higher cold tolerance
than Coastal, Midland and Tifton 44.
Established from sprigs, its quality is
very similar to other bermudagrasses.
It is best adapted to sandy to sandy
loam type soils and responds well to
nitrogen fertilizer.
Carostan flaccidgrass
This is a variety of flaccidgrass (Pennisetum flaccidum) released by the
North Carolina Agricultural Research
Service. Flaccidgrass is an introduced
species from Central Asia. It has an
erect growth habit and can reach
heights of 4 feet tall or more if not
harvested. Flaccidgrass produces few
viable seed, which has resulted in limited availability of seed and high cost.
It can also be established from sprigs.
Ermelo weeping lovegrass
This variety of lovegrass (Eragrostis
curvula) was developed by the Texas
Research Foundation. Lovegrassses
were introduced to the United States
from South Africa in the 1940s. They
tend to green up and begin forage production earlier than other
warm-season perennials and tolerate
droughty, coarse sandy soils better
than many other types of forage.
Lovegrass is a strong bunch-type
grass established from seed.
FORAGE
Morpa weeping lovegrass
Morpa weeping lovegrass is a variety of lovegrass (Eragrostis curvula)
released in 1970 by the Oklahoma
Experiment station and the USDA. The
agronomic characteristics are similar
to Ermelo.
Johnsongrass
Johnsongrass (Sorghum halepense)
owes its name to Colonel William
Johnson, who introduced the grass to
central Alabama around 1840. Native
to the Mediterranean area of North
Africa, it spreads by both rhizomes and
seed. Johnsongrass will persist well in
hay production, but not under close,
frequent grazing. Though it has good
drought tolerance, it is listed as one
of the 10 most noxious weeds in the
world. It can accumulate nitrates under
dry weather conditions and develop
prussic acid potential when stressed.
Johnsongrass is established from seed
in the spring.
Johnsongrass
Blue panicgrass
A native of southern Asia, Blue panicgrass (P. antidotale) is a bunchgrass
that can vegetatively reproduce from
rhizomes. It is very erect in its growth
habit and can reach heights of 5 feet
or more at maturity. Blue panicgrass is
established from seed.
Lometa indiangrass
This variety of indiangrass (Sorghastrum nutans) was released in 1981 by
the Texas A&M Agricultural Experiment
Station and the USDA. It was developed from seed collected from a
native stand at Lometa, Texas. Indiangrass is a loose bunch-type grass with
short rhizomes. It can form a weak sod
under grazing pressure. Indiangrass is
established from seed.
Pensacola bahiagrass
Pensacola bahiagrass is a variety of
bahiagrass (Paspalum notatum) which
is native to South America and was
introduced to the United States in the
early 1900s. The Pensacola variety was
developed from a collection of plants
found by a Florida county Extension
agent near Pensacola, Fla. Pensacola is
a winter-hardy variety and is the most
common variety of bahiagrass at the
present time. Bahiagrass forms a very
dense sod that is tolerant of close, continuous grazing. It also tends to tolerate a wider range of soil types, greens
up earlier in the spring and stays
greener longer in the fall than bermudagrass. It is not as drought resistant
as bermudagrass. At low fertility levels,
it can become a very serious weed in
bermudagrass. Bahiagrass is established from seed in the spring.
Sand Mountain bahiagrass
This is a new release of bahiagrass
(Paspalum notatum) developed by
Auburn University. It was selected to
have more winter hardiness than the
varieties Pensacola or Argentine, but
with agronomic characteristics similar
to Pensacola.
Bahiagrass
Dallisgrass
A native of South America, dallisgrass
(Paspalum dilatatum) is best adapted
to clay type soils with good moisture.
Established from seed, germination
can be low, resulting in slow stand establishment. Seed heads can become
infected with ergot, which can reduce
seed set and, on rare occasions, cause
ergot toxicity in cattle.
WW-B Dahl old world bluestem
This is a variety of old world bluestem
(Bothriochloa bladhii) released in 1994
by Texas Tech, the Texas Agricultural
Experiment Station and the Soil Conservation Service (Natural Resources
Conservation Service). It is a bunch
type grass developed to have a higher
leaf-to-stem ratio than other old world
bluestem grasses. It can reach heights
of 3 to 3.5 feet at maturity. Established
from seed in the spring, the cold tolerance of WW-B Dahl has been questioned.
Old world bluestem
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Samuel Roberts Noble Foundation
FORAGE
Results and Discussion
The grasses were harvested on four
dates in 2005 with dry matter production reported in Table 1. Only grasses
that were harvested more than once
in 2004 and 2005 were included in the
two-year average yield data.
Blackwell switchgrass, Sand Mountain
bahiagrass and WW-B Dahl old world
bluestem were harvested only once
in 2004 and were not included in the
2004 or two-year average summaries.
Sand Mountain bahiagrass is a new
entry into the test, being established
in spring 2004. Johnsongrass and
Carostan flaccidgrass experienced a
reduction in yield from 2004 to 2005
by 30.7 percent and 18.6 percent
respectively. All other grasses in 2005
either increased in yield or decreased
by only 8 percent or less. Rainfall during the actual harvest period was 2.65
inches less in 2005 than in 2004. This
could indicate a higher sensitivity to
drier conditions than other grasses in
the study. Blue panicgrass increased
in yield from 2004 to 2005 by 5,146
pounds per acre. This yield increase is
due to improvement in stand density
and indicates that the yield has probably not yet stabilized.
The grasses in this study vary greatly in
their growth types, but these differences are not necessarily reflected in
dry matter yield (Table 5). With the exception of Alamo switchgrass, the tall,
upright, bunch type grasses (Alamo
switchgrass, Selection 75 kleingrass,
Carostan flaccidgrass) are very similar
in yield to some of the shorter, more
sod-forming type grasses (Midland 99
bermudagrass, Pensacola bahiagrass).
Alamo switchgrass has consistently
out yielded all other entries in the
study (P<.05) over the last two years.
However, in a grazing situation, these
morphological differences would
probably become more apparent as
the tall, upright, bunch type grasses
tend to be less resistant to grazing
pressure.
Table 2 graphically displays yield and
distribution for the 2005 harvest. It
should be noted that these plots were
not on a set harvest schedule, but
rather a maturity schedule with plots
being harvested at the boot to early
head stage of development. Only two
of the grasses (Blue panicgrass and
Pensacola bahiagrass) were harvested
at each harvest date.
Table 3 is a production index, which
helps to determine the yield stability
of the grasses. It is determined by dividing the two-year dry matter yield of
the individual grass by the overall two
year average dry matter yield. Sand
Mountain bahiagrass, WW-B Dahl old
world bluestem and Blackwell switchgrass were eliminated from this index
as they were harvested only once in
2004.
Quality data is presented in Table 4.
Data collected in June and August was
not replicated, and statistical analysis
could not be done. Only the October
harvest was replicated and statistically
analyzed. At the early harvest of June
7, all entries have good quality for beef
cow production with crude protein
(CP) above 9 percent and total digestible nutrient (TDN) values in excess of
55 percent. As the season continued,
CP levels had dropped substantially,
which is to be expected under hot, dry
conditions, but TDN levels were still
close to or above 55 percent.
Switchgrass
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FORAGE
Table 1. Dry forage yield of warm-season perennial grasses, 2005
2005
Clipping dates
Species or Variety
June 7
June 29
Alamo switchgrass
Selection 75 kleingrass
Midland 99 bermudagrass
Ermelo weeping lovegrass
Carostan flaccidgrass
WW-B Dahl
Pensacola bahiagrass
Lometa indiangrass
Morpa weeping lovegrass
Johnsongrass
Blue panicgrass
Dallisgrass
Blackwell switchgrass
Sand Mountain bahiagrass
7,971
5,384
5,330
4,861
4,452
2,841
3,570
4,335
889
4,619
2,487
4,186
1,352
4,814
1,008
4,182
-
Average
L.S.D. (.05)
C.V. (%)
4,249
1,240
17
3,018
2,971
54
Aug. 11
Pounds/acre
6,041
4,632
3,969
3,606
4,316
3,250
3,448
2,853
4,188
3,489
1,983
3,798
1,822
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Oct. 5
Total 2005 Total 2004
2-year Average
(2004-2005)
3,176
2,456
2,635
2,853
1,975
6,306
2,480
5,069
2,548
2,198
2,699
4,482
2,287
17,189
12,472
11,934
11,320
10,742
10,492•
9,923
9,882
9,568
9,386
8,784
8,664
8,108•
6,757•
14,411
13,559
11,606
11,527
13,205
*
10,294
6,250
10,307
13,539
3,638
6,610
*
*
15,800
13,016
11,770
11,424
11,974
*
10,108
8,066
9,937
11,462
6,211
7,637
*
*
3,166
1,336
25
10,373
2,931
17
10,450
2,780
16
10,673*
2,280*
12*
•Blackwell switchgrass, Sand Mountain bahiagrass and WW-B Dahl old world bluestem dry matter yields from 2005 are not included in
the two-year average summary due to incomplete data in 2004.
*Blackwell switchgrass, Sand Mountain bahiagrass and WW-B Dahl old world bluestem were harvested only once in 2004 and not
included in the 2004 or two-year summary data.
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Samuel Roberts Noble Foundation
FORAGE
Table 2. Yield and distribution for 2005
A*
Alamo switchgrass
B
Selection 75 kleingrass
BC
Midland 99 bermudagrass
BCD
Ermelo weeping lovegrass
Carostan flaccidgrass
BCDE
WW-B Dahl
BCDE
Pensacola bahiagrass
BCDE
Lometa indiangrass
BCDE
Morpa weeping lovegrass
BCDEF
7-Jun
29-Jun
11-Aug
5-Oct
CDEF
Johnsongrass
Blue panicgrass
DEF
Dallisgrass
DEF
Average Yield 10,373
EF
Blackwell switchgrass
F
Sand Mountain bahiagrass
0
5000
10000
pounds per acre
15000
80
120
20000
*Bars with differing letters are significantly different P=0.05
Table 3. Two year production index
Alamo switchgrass
Selection 75 kleingrass
Carostan flaccidgrass
Midland 99 bermudagrass
Johnsongrass
Ermelo weeping lovegrass
Pensacola bahiagrass
Morpa weeping lovegrass
Lometa indiangrass
Dallisgrass
Blue panicgrass
0
20
40
60
Samuel Roberts Noble Foundation
100
140
160
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FORAGE
Table 4. Quality data 2005 harvest
June 7
Clipping Dates
June 29
Aug. 11
%CP
%TDN
%CP
%TDN
Species or Variety
%CP
%TDN
Alamo switchgrass
9.7
56.6
-
-
7.0
Selection 75 kleingrass
Midland 99 bermudagrass
12.1
17.9
58.1
64.5
-
-
Ermelo weeping lovegrass
11.0
57.8
-
Carostan flaccidgrass
15.9
60.0
13.3
WW-B Dahl
Pensacola bahiagrass
Lometa indiangrass
Oct. 5
%CP
%TDN
56.2
8.2
58.2
6.0
6.4
54.6
58.0
5.9
8.1
55.9
59.3
-
7.6
54.0
6.3
53.0
-
-
6.7
55.0
6.5
54.3
-
12.1
61.0
-
-
3.4
52.0
58.2
13.3
58.6
7.6
56.4
6.5
54.8
-
-
11.2
58.0
-
-
5.5
52.5
Morpa weeping lovegrass
12.7
59.2
-
-
6.8
54.3
6.1
52.9
Johnsongrass
10.1
56.1
-
-
7.1
56.0
6.9
54.9
Blue panicgrass
17.1
60.2
19.4
65.0
9.1
57.0
5.2
53.5
-
-
15.3
60.6
-
-
5.6
51.6
Blackwell switchgrass
12.7
60.0
-
-
7.5
57.0
-
-
Sand Mountain bahiagrass
15.3
62.0
-
-
7.7
57.3
7.4
55.7
Average
13.4
59.3
14.3
60.6
7.2
55.9
6.2
54.5
L.S.D (.05)
2.0
2.28
C.V. (%)
19.2
2.49
Dallisgrass
Table 5. Morphological characteristics of warm-season perennial grass entries and 2005 yield
2005 Dry matter
Yield lbs/ac
Growth Type
Alamo switchgrass
Tall, upright, bunch type, weakly rhizomatous
3
17,189a*
Selection 75 kleingrass
Tall, upright, short rhizomes, weak bunch type
3
12,472b
Midland 99 bermudagrass
Sod forming, numerous rhizomes and stolons,
intermediate in height
3
11,934bc
Ermelo weeping lovegrass
Strong bunch type, upright
3
11,320bcd
Carostan flaccidgrass
Upright, tall, weak bunch type, rhizomatous
3
10,742bcde
WW-B Dahl
Tall, upright, bunch type
2
10,492bcde
Pensacola bahiagrass
Sod forming, produces stolons, prostrate
4
9,923bcde
Lometa indiangrass
Loose-bunch type, short rhizomes
2
9,882bcde
Morpa weeping lovegrass
Strong bunch type, upright
3
9,568bcdef
Johnsongrass
Tall, upright, rhizomatous
3
9,386cdef
Blue panicgrass
Tall, very erect, rhizomatous
4
8,784def
Dalligrass
Bunchgrass, short rhizomes, can be prostrate with grazing
pressure; upright otherwise
2
8,664def
Blackwell switchgrass
Tall, upright, bunch type, rhizomatous
2
8,108ef
Sand Mountain bahiagrass
Sod forming, produces stolons, prostrate
3
6,757f
*Numbers with differing letter are significantly different P = 0.05
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No. 2005
Harvest
Species or Variety
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FORAGE
Summary
With two years of production data collected by maturity stage, grasses are
beginning to separate by yield (Table
3). Forage quality appears to be somewhat similar for the grasses, but will
be further evaluated. When evaluating
these data, producers should not overlook some of the lower-yielding varieties. While yield is important, it is only
one of many factors producers should
evaluate when making a selection
decision. Producers should also keep
in mind that between harvests, these
grasses received ample rest periods
as harvests were triggered by plant
maturity rather than a set harvest
schedule. This would be more typical
of a hay production system rather than
grazing. Under grazing pressure, dry
matter production could be somewhat
different than what is represented with
these data.
Influencing Factors
Location: Pasture Demonstration Farm, Ardmore, Okla.,
Latitude 34.22580478, Longitude -97.21239110
Soil Type: Wilson (Fine, montmorillonitic, thermic Vertic Ochraqualfs)
Plot Size: 8 feet x 20 feet
Replication: Randomized complete block design with three replications
Fertilizer: 70 pounds per acre equivalent of N applied on April 18, 2005.
The plot area was soil tested on March 22, 2005, and indicated a pH of 6.40,
62 pounds per acre of extractable phosphorus and 220 pounds per acre of
extractable potassium.
Weed control: Plots were sprayed with 2 qts/ac of 2, 4-D on June 1, 2005.
Harvest procedure: Plots were harvested when grasses reached the boot
to early head stage of development. Residual harvest height was based on
species. Residual height for native grass was 4 to 6 inches and 3 inches for
introduced grasses.
Rainfall (Inches)
Month
102-year
average
2004
2005
January
1.78
1.18
4.79
February
2.06
3.69
1.97
March
2.90
1.46
0.73
April
4.03
4.27
0.26
May
5.21
0.54
3.57
June
3.98
8.1
2.51
July
2.71
5.52
5.13
August
3.43
2.0
6.29
September
3.59
0.31
2.57
October
3.71
6.68
3.46
Total
33.4
33.75
31.28
Thanks to Julie Barrick and Frank Motal for all their help in the collection and
analysis of data presented in this publication.
Samuel Roberts Noble Foundation
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