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Ft. Pierce AREC Research Report FTP 90-1
'CALLIDE' RHODESGRASS FOR GRAZING
AND STORED FEED IN SOUTH FLORIDA
^ FEB 2 8 199(
1--~ ~.i'-'crc _y e .F'^'''''
Albert E. Kretschmer, Jr.
Professor of Agronamy, IFAS, Agricultural Research and
Education Center, (ARECFP), P. 0. Box 248, Ft. Pierce, FL 34954
Ft. Pierce AREC Research Report FTP-90-1 February 1990
'CALLIDE' RHODESGRASS FOR GRAZING AND STORED FEED IN SOUTH FLORIDA
Albert E. Kretschmer, Jr.
Professor of Agronomy, IFAS, Agricultural Research and
Education Center, (ARECFP), P. O. Box 248, Ft. Pierce, FL 34954
This report is written to inform growers of the attributes of the cultivar
'Callide' rhodesgrass (Chloris gayana Kunth.). Rhodesgrass, originally from
Africa, is now widespread in the tropical and subtropical areas of the world
where annual rainfall is above about 25 to 30 inches. Its altitude limits for
growth in the Equatorial zone are between 2000 and 7000 feet. As latitudes
increase, it grows best at lower altitudes. Natural habitats of this African
stoloniferous grass include grasslands, open areas with scattered trees, river
and lake banks and seasonally waterlogged plains.
Callide rhodesgrass seeds were imported by a Florida seed company in 1988
and several commercial plantings have been made. Because of its success
elsewhere and its potential in Florida, cattlemen should be aware of its
There are many ecotypes of rhodesgrass and same of the information in this
report deal with rhodesgrasses other than the Callide rhodesgrass cultivar.
This additional information is provided to give a general indication of the
attributes of the species, either by itself or in relation to other better
known grasses. Some of the information in this report may change as more field
results from Florida became available. To be more applicable to Florida
growers, months from Rhodesia and Australia (southern hemisphere) have been
converted to correspond to Florida climatic months.
Rhodesgrass (Chloris gayana Kunth.) is a member of the same tribe as
bermudagrass, the Chlorideae. It was described as a species in 1829. It is a
perennial herbaceous grass with erect or stoloniferous culms (stems)
(Lazarides, 1972). As stolons grow, rooting occurs at each node of the
stoloniferous culm. Two to four leaves emerge from the nodes (Fig. 1) (Bogdan,
1969); (Chippindall, 1959).
Rhodesgrass leaf blades can be up to 20 inches or more long and 1/4 to 1/2
inches wide depending on ecotype. Callide, a tetraploid (2n=40), is one of the
more vigorous, large ecotypes, with leaves up to 17 or more inches long and
with up to four leaves per erect culm (measurements made at the ARECFP).
Rhodesgrass can grow to 6 feet high when in full flower. More typically
plants will attain a height of 3 to 5 feet when flowering. The panicle or
branched inflorescence is comprised of spikes and spikelets (Fig. 1, Fig. 2).
Fig. 1. Rhodesgrass: Plant x 1/2; 1.
of one spikelet x 6;
Part of spike x 5;
3. Ligule x 4.
From: L.K.A. Chippindall, The Grasses and Pastures of South Africa
d 2ND FLORET
Generally, the number of spikes per panicle varies with a maximum of about 20
(Lazarides, 1972; Bogdan, 1966; Bogdan, 1969; Bogdan, 1977). At the ARECFP, N
fertilized or non-fertilized Callide (in the fall) had about 10 spikes per
panicle. Sometimes there are two whorls of spikes per panicle. The number of
spikelets primarily depends upon the length of the spike. Each spikelet is
cciprised of 2 to 3, or occasionally 4 florets with longer awns on the lower
than on the second floret. Other florets do not have awns. The awns in
Callide are unusually long (about 1/4 to 3/8 inches), as are the long tufts of
hair at the base of the awns.
Normally a grain (cariopsis) is produced only in the lower floret,
although sometimes a smaller one is formed in the second floret. Grain can
easily be dislodged from the floret when it is roughly handled. Grain size
varies but may be about 2 mm long and 0.5 mm wide. It is spindle shaped,
glassy, and translucent from almost colorless to reddish brown (Fig. 2). Grain
tends to turn darker red in color as storage time increases. Seed viability is
maintained for up to 5 years, depending on temperature and humidity of the
The sequence of flowering to mature seed begins with the panicle emerging
from the uppermost leaf sheath. About 14 to 16 days later the panicle opens
and flowering begins (Bogdan, 1969). Flowering begins at the middle of a spike
and proceeds towards both ends. In each spikelet the first (lowest) floret
flowers first, followed by the second 3 to 4 days later, and lastly by the
third floret, if present. Flowering begins only under direct sunlight and may
be delayed until late in the afternoon, or not at all without direct sunlight.
All flowering occurs simultaneously in all panicles of the same age in each
plant and in all plants in the field with the emergence of the anthers and the
release of pollen, which takes 6 to 12 minutes. The grain reaches full size in
about 10 days after flowering but is not fully ripe until another 13 to 15
days. Weather can influence pollination and seed development and, therefore,
Rhodesgrass is native to tropical Africa from Ethiopia to Zimbabwe across
the equatorial belt of the Congo basin. It has been introduced into tropical
and subtropical areas throughout the world. It was named after Cecil Rhodes
who introduced it into cultivation in South Africa in 1895 (Cameron, 1967).
This grass eventually became known as 'Pioneer' rhodesgrass in Australia where
it was tested in New South Wales in 1902-3 (Anon., 1972; Davies, 1951), and
"rhodesgrass" in the United States and elsewhere. Recently, several cultivars
have been released.
'Callide' rhodesgrass was previously known in Africa as 'Giant', 'Mpwapwa'
(Kenya), or 'Kongwa' (Tanzania); was introduced into Zimbabwe from Tanganyika
in 1937 (Hanssen, 1975; Grof, 1961), and from there into Australia by the
Queensland Department of Primary Industries, as Q3307. It was given its
cultivar name in 1963 (Grof, 1961; Anon., 1972; Davidson, 1966).
Rhodesgrass has been tested in most tropical and subtropical climates,
with most published information on its use coming from Australia. Seed was
brought to the U.S.A. by the U.S.D.A. from the farm of Cecil Rhodes, near
Capetown, in 1909.
Rhodesgrass was first planted in Florida at the Florida Agricultural
Experiment Station, Gainesville, in 1909. Results of its performance were
published by P.H. Rolfs in 1917 in the Florida Agricultural Experiment Station
Bulletin 138. It was considered a promising grass although loss of stand could
occur during severe winters (Boyd and Sleper, 1974). Rhodesgrass was
introduced into the ARECFP from Australia in 1963. It was introduced to Texas
ranches in 1912.
Temperature. Rhodesgrass respiration increases almost linearly from 50 to
1220 F. Under controlled conditions at maximum-minimum temperatures of 59/50,
81/72, and 97/880 F, rhodesgrass (presumably Pioneer) relative growth rates
ware 22, 91, and 100%, respectively. The optimum growth temperature was
similar to that for guineagrass; buffelgrass and Setaria sphacelata reached
100% of their potential at slightly lower temperatures, and fescuegrass at much
lower temperatures (Kawanabe, 1968).
Frost damages rhodesgrass foliage as easily as that of Pangola digitgrass,
but regrowth after frosts is much faster than Pangola; thus overall production
during the cool season is greater than Pangola (Kretschmer, 1974).
Although probably not as frost tolerant as Pioneer (Hutton, 1961), Callide
survived air temperatures of 17 to 22 F in three widely separated locations in
south Florida during the freeze of December 1989. An example at the ARECFP,
west of Ft. Pierce, reflects the general temperature fluctuations that existed
in south Florida on 24 and 25 December 1989 (Fig. 3). There were about 15
hours with temperatures below freezing and about 8 hours below 28 F. In
addition, the average total number of hours below 32 and 28 F from 5 locations
in the St. Lucie Co. area were 28 and 20, respectively (data obtained from Dr.
Brian Baman, ARECFP). At the ARECFP, Ona AREC, and at the Willowbrook Dairy
(southwest of Palm Bay), Callide, which was frozen to the ground, began to
recover in about a week as evidenced by new leaves forming from the crown areas
of original or stoloniferous rooted plants. At the ARECFP, green foliage,
that had been 30 to 36 inches high prior to freezing and lodging, measured
from 6 to 10 inches three weeks after the freeze even when the dead foliage was
not removed. In a part of the field where the Callide had been mowed to a
height of 2 to 3 inches a week prior to the freeze, regrowth appeared more
rapid than that where frozen foliage had been left. Regrowth of Callide was
more rapid than that of Pangola and bahiagrass in nearby fields. At the
Willowbrook Dairy, a low air temperature of 17 F was reached with about 48
hours of continuous, below-freezing temperatures. Recovery from the freeze was
more rapid than that of adjoining stargrass pastures. Five weeks after the
freeze, Callide regrowth was 12 to 15 inches and there were many areas where
Callide seedlings (seed from 1989 plants) were up to 4 inches high.
Rhodesgrass in Uruguay and Argentina survived temperatures below 320 F and
numerous frosts (Bogdan, 1969). In the USSR, temperatures below 14 F killed
rhodesgrass. In Texas, temperatures of 15 F killed most rhodesgrass, but a
cold resistent introduction withstood 60 F (Bogdan, 1969). Also, in Texas, 12
to 15 F temperatures did little permanent damage to rhodesgrass 10 or more
inches high (cultivar unknown, but probably Pioneer) (Lancaster, 1949). In the
USSR, field germination of seeds was observed at between 50 to 540 F.
50- Ft. Pierce AREC
50- Salinity Experiment
L. Dec. 23-26, 1989
"I~----- -- -- -- --- -
E --------------- ------ -------- -------------------
00 12 00 12 00 12 00 Hour
23 24 25. Date
From these data and observations, it appears that Callide plants will not
be killed when air temperatures fall to 17 to 22 F for several hours, and that
the northern limit of Callide rhodesgrass lies between the Orlando and
Gainesville regions. With proper selection or breeding of more freeze
resistant cultivars, the northern limit could be increased. Because the
potential summertime production of rhodesgrass is about 8 to 10 tons of dry
matter per acre in Gainesville (Boyd and Sleper, 1974), this species could
provide an excellent surmner-growing forage in an area almost completely
dominated by bahiagrass.
Cool Season Growth. Research during 10 years at the ARECFP revealed that
several rhodesgrass cultivars and entries had excellent growth attributes in
south Florida for cool-season grazing or for stored feed (Kretschmer, 1974).
From 1966 to 1971 yield of cool-season regrowths of four rhodesgrass
entries was compared with Pangola. Grasses were cut in early September for
staging and yields were measured on 4 November, 1 February, 1 May, and 11 June.
A mixed fertilizer supplying 75 lb/acre of nitrogen was applied after staging
and after each harvest. In Table 1 the results are presented only for
'Katambora' rhodesgrass (Callide was not included) and 'Pangola'digitgrass,
since the other rhodesgrass entries yielded similarly to Katambora. Plot
coverage at the end of four seasons for Katambora and Pangola was 100 and 98%,
respectively. There was no change in relative productivity between grasses
during the progress of the experiment.
Table 1. Average four-year dry matter yields of Katambora rhodesgrass and
Pangola during the cool season at the ARECFP.
Grass Cutting Interval
4 Nov. 1 Feb. 1 May 11 June Total
56 days 89 days 89 days 41 days
Rhodes 2130 2220** 2650** 2810 9810
Pangola 2420 950 1630 2870 7870
** = Statistically significant at the 1% level of probability between
In a similar test from 1972 to 1974 from fall to spring, one of the
rhodesgrass entries from the previous experiment was compared with Pangola and
'Coastcross-1' bermudagrass (Fig. 4). Plots were staged on 26 September of both
years and fertilized with 75 Ib/acre of nitrogen after staging and each
harvest. During the 2 years, rhodesgrass production was significantly higher
than Pangola in 8, and Coastcross-1 in 5 of 12 harvests.
Regrowth of rhodesgrass after cutting is rapid and very similar to that of
guineagrass in that new shoots emerge in an erect manner from crown areas
rather than from lateral shoots as with Pangola.
A cutting experiment at the ARECFP was done in 18-inch diameter open-ended
culverts buried in the soil, to compare a vigorous introduction of rhodesgrass
11 NOV 27 DEC
Fig. 4. 2-year average dry weight yield
of Rhodesgrass, Pangola, and Coastcross-
1 bermudagrass during the cool season.
with Pangola and Coastcross-1. Cutting intervals for the 24-week 28 November
1973 to 15 May 1974 period were 2, 3, and 4 weeks. From 28 November until 20
February (12 weeks), Coastcross-1 yield at the 2-week interval was better than
that for the others and no difference existed among other cutting intervals.
For the second 12-week period, there was no yield differences for the 2-week
interval, but rhodesgrass yield was highest, and better than Pangola for the 4-
week cutting interval. For the total 24-week period, rhodesgrass yielded more
than the others at the 3-week interval, but there were no other differences.
In other experiments, Mislevy and Hodges (1974) found the same rhodesgrass
entry to be 40% more productive when grazed at 4 compared with 3-week
Site Adaptation. On flatwoods soils it is believed that Callide
rhodesgrass and bahiagrass have a similar tolerance to periodic flooding or
waterlogging conditions. On the other hand, it is doubtful that Callide will
tolerate standing water as well as Bigalta limpograss. Site adaptation may be
similar to that for Pangola. On upland or better drained sites it should
persist well since it is more drought tolerant than Pangola.
Weed Competition. Callide rhodesgrass establishment is faster than that
of vegetatively planted grasses. When a good seedling plant population exists,
it should compete well with common bermudagrass and bahiagrass seedlings. It
is doubtful that Callide would eliminate plants of these grasses that were
present prior to seeding. If a large portion of the pasture being renovated
contains bahiagrass and common bermudagrass, every effort should be made to
kill them prior to seeding Callide.
Legume Compatibility. High cattle acceptance of Callide may offset its
competitive vigor. When adequate potassium was present, berseem clover was
successfully grown with rhodesgrass during the dormant season in Israel
(Dovrat, 1966). In Malawi, Siratro and Silverleaf desmodium (two summer-
growing legumes), mixed with rhodesgrass, survived different grazing regimes
for three years (Thomas, 1976). Also, Stylosanthes guianensis, S. humilis,
Neonotonia wightii, Greenleaf desmodium, cowpeas, and white clover have been
grown successfully with rhodesgrass, although same other attempts were not
successful (Bogdan, 1969).
At the ARECFP, rhodesgrass was grown in mixture with each of seven
tropical legumes for two years (Kretschmer, 1982). Yield of rhodesgrass-legume
mixtures compared favorably with those of other grass-legume mixtures. The
percentage of Centrosema pubescens, carpon desmodium, and Stylosanthes
guianensis (cv. Endeavour) mixtures changed from 48, 76, and 15%, respectively,
in July 1976 to 0, 0, and 20% by January 1977. Average crude protein for
rhodesgrass mixture regrowths (legumes averaged) from 17 Sept. to 10 Dec. and
from 7 July to 17 Dec. were 13 and 11%, respectively, while IVOMD percentages
were 49 and 39%. These were comparable to other grass-legume mixture values.
It is believed that aeschynomene, carpon desmodium, and white clover will
compete favorably with Callide if grazed to prevent accumulation of large
quantities of grass.
In one Australian experiment (southeast Queensland) a supplement of urea-
salt-molasses was compared with no supplement using weaned steer and heifer
cattle weighing about 380 lb. Rhodesgrass received 60 lb/a of nitrogen in
September (March Australian time) and cattle grazed from 21 December to 28
March. Lack of response to the supplement was attributed to the adequate
protein and forage present during the test (Jones, 1966).
Katambora rhodesgrass was included in a grazing experiment with steers
with mean maximum and minimum temperatures from June to the middle of October
(December to April in Rhodesia) of 59 to 640 F, and 50 to 570 F, respectively;
and 42 to 470 F in November and December (Addison, 1959). Continuous, and 2,
4, and 6-week rotational grazing commenced in June and was discontinued the
first week in December. Little rain fell during September and November.
Regardless of grazing management, daily live weight gains were about 2
Ib/animal/day until early September; and 1 lb/animal/day from then until the
beginning of November when all animals started losing weight. The loss of
weight was attributed to the lack of forage intake due to insufficient protein
(which fell below 5%). Grass growth was reduced as minimum temperatures fell
below 60 F and almost ceased below 50 F.
In south Florida, information on grazing Callide is limited to
observations. It is known that Callide will be very heavily and selectively
grazed when cattle also have access to bahiagrass. Near Okeechobee, when
Callide was permitted to grow during the entire summer season without grazing
(40 lb/a nitrogen) until November, cattle grazed the 5-foot grass down to 12 to
15 inch stems. When first grazed the crude protein was 6.2% and IVOMD was
58.7%. In another similar observation on flatwoods soil where no nitrogen was
applied, Callide was consumed very well to the largest stem portions compared
to the bahiagrass that was in the same field. In a small pasture with
volunteer bermudagrass and bahiagrass and only a few plants of Callide, the
bahiagrass and bermudagrass were grazed lightly. However, the Callide was
overgrazed to the point that only stolons were present at the end of the
establishment year. It was believed that the Callide would not survivethe
winter because of the over-grazing. Surprisingly, plants continued to spread
during the next summer in spite of the second year's overgrazing.
In a mob grazing test at Ona (Mislevy and Hodges, 1974), a rhodesgrass
introduction prevented the encroachment of common bermudagrass into the small
Because of the lack of information, it is suggested that Callide should be
grazed in a manner similar to that for Pangola or stargrass. This will permit
adequate growth and maintain a good stand. A rest period should be provided
during the growing season. In Texas, it was suggested that rotational grazing
would be a good management decision because it would permit the formation of
less palatable stems which would, in turn, protect new growing shoots from
Callide is particularly adapted to deferred fall stockpiling. Also, it
could be cut for hay in October early November, refertilized, and
subsequently grazed about the first of December.
Callide and other rhodesgrasses are well suited for cutting because of
their erect growth habit and rapid regrowth when adequately fertilized.
Rhodesgrass makes high quality hay (Lancaster, 1949) and can be cured rapidly
compared with Pangola and limpograss. Because of its high acceptability by
cattle (Anon., 1972), it is readily consumed even in a mature stage.
Rhodesgrass makes lactic acid silage as do other tropical grasses
(Catchpoole and Williams, 1969). It ensiles well without added sugar
(Catchpoole, 1965). Depending on the quantity of nitrogen fertilizer applied
and the length of regrowth, crude protein levels similar to those for Pangola
and stargrasses can be expected with dry matter contents of 20 to 30% when cut.
Results from Florida commercial plantings are not complete, but the mechanical
aspects frmr cutting to silage packing caused no additional problems compared
The acceptability (palatability) of rhodesgrass is excellent and at least
equal to Pangola (Alcantara, et al., 1980).
There have been several Australian experiments using hay and sheep to
determine the nutritive value of rhodesgrasses. In one (Milford and Minson,
1968), six rhodesgrass entries were cut after 42, 63, 105, and 140 days of
regrowth, dried at 1870 F, and chafed into 1 to 2 inch lengths. In addition,
four monthly regrowths of all entries were hayed in a similar manner. Urea was
applied to supply 150 lb/a of nitrogen prior to the first cut and after
additional cuts, and the areas were irrigated after fertilization. Marino
wethers were fed the various hays. Callide's crude protein, digestibility, and
intake values were similar to those for 'Samford', Pioneer, and the 3 non-
cultivars (Table 2).
Table 2. Crude protein and digestibility of Callide rhodesgrass at
different regrowth intervals.
Cutting Crude Digestibility
Interval Protein DM' CM+ Intake
% % % g/kg W 0.75
July++ 14.5 64.3 67.1 51.5
August 15.7 65.6 67.4 53.2
September 18.1 65.4 68.9 53.5
October 15.4 59.0 64.3 45.7
42 days (July) 10.4 57.0 59.0 43.1
63 days (Nov.) 11.3 61.1 63.6 39.7
105 days (Jan.) 8.8 56.2 58.9 40.8
140 days (Feb.) 9.4 49.3 51.5 41.2
+ Dry matter
++ Organic matter
+++ January in Australia; staged on 10 June, and cut at monthly intervals
except for intervals listed.
Statistically, there was no fall in digestibility with increasing age of
regrowth (42 to 140 days), however, values presented in Table 2 decreased.
Intake was not affected by regrowth interval. There were no differences among
entries' digestible dry matter for monthly cuts (Milford and Minson, 1968).
The six rhodesgrass entries covered a wide range of growth forms which
indicates that, among rhodesgrass cultivars or ecotypes, it may be difficult to
select for superior feeding value.
In a second experiment, Callide and Samford rhodesgrasses were compared
using the same technique as above and the same nitrogen rate (Minson and
Milford, 1967) (Table 3).
Table 3. Characteristics and feeding value of Callide and Samford rhodesgrass when fed
as chafed hay to sheep.
Harvest Regrowth Yield Leaf+ Crude Intake of Digestible Voluntary
Date Days protein DM" DM DM intake
lb/a % % g/kg W 0.75 % g/kg W 0.75
C# S# C S C S C S C S C S
26 Aug.## 50 5200 4800 52 41 8.9 13.6 53.0 54.1 60.4 55.3 32.0 29.9
7 Oct. 90 9700 NR 28 28 4.9 8.9 38.0 47.5 49.5 49.6 18.8 23.6
8 Nov. 153 10100 6100 30 25 3.3 8.8 29.0 47.6 42.7 46.0 12.4 21.9
13 Dec. 188 12100 6200 20 20 3.1 7.3 26.5 39.5 40.0 43.9 10.6 17.3
) Percentage weight of leaves in harvested foliage
+ DM = dry matter
# C = Callide; S = Samford
S26 Aug. = 26 Feb. Australian time. Staged for initial cut on 17 July.
Sheep ate all feeds well except the 188-day Callide regrowth. The
superiority of the Samford cultivar for 90, 153, and 188-day regrowths can most
easily be explained by the limiting effect that low crude protein levels had on
reducing intake of Callide. The low protein in Callide, in turn, can be
explained by dilution effects from its much higher yields.
Pangola and an Australian (CPI 16710) rhodesgrass entry were compared
using wethers (Minson, 1972). Nitrogen was applied at 50 or 200 lb/a and
irrigated 28 days prior to 28-day harvests at five dates (Table 4). There was
no limit of protein on voluntary intake nor a correlation between digestible
dry matter and crude protein levels; and no effect of applied nitrogen rate on
In another similar experiment, chaffed hay (1-2 inches long) of Pangola
and CPI 16710 rhodesgrass were compared using sheep (Table 5) (Minson, 1973).
The results show the acceptable quality and feeding value of rhodesgrass
compared with Pangola.
Table 4. Effect of two nitrogen rates and season on yield and feeding value of
Pangola and rhodesgrass.
----------- b/a ---------- ----------- % ----------
L# H L H L H L H
June## 2700 4300 1900 3400 12.8 14.2 9.7 15.3
July 3200 5000 2400 4300 9.6 14.2 9.4 15.3
August 3700 7300 3700 3500 7.9 11.8 7.4 11.7
March 1600 1600 --- --- 10.4 16.3 --- --
April 1300 2300 2000 2800 12.8 14.2 6.0 10.1
Harvest Digestible Intake
Date DM@ DM@
------------ % ---------- -------- g/kg W 0.75
L H L H L H L H
June 61.5 63.0 63.4 67.2 65.4 68.1 64.8 65.3
July 59.3 64.1 63.5 63.4 63.9 64.7 61.8 65.4
August 59.8 59.3 55.9 57.9 59.1 58.6 52.4 60.9
March 60.8 64.6 ---- ---- 69.3 72.5 ---- --
April 52.6 59.5 56.5 60.3 57.4 67.7 66.1 70.2
+ Fertilized 28 days before first and subsequent 28-day harvest dates.
++ R = rhodesgrass; P = Pangola
# L = 50 Ib/a of nitrogen; H = 200 Ib/a of nitrogen
## December in Australia
@ DM = dry matter
The effect of age on In vitro dry matter digestibility (IVDMD) was
determined during a 16-week period with three rhodesgrasses receiving 50 lb/a
of nitrogen at staging. Data for the mean IVOMD for the three grasses are
shown in Fig. 5 (Reid, et al., 1973). The decline in digestibility was found
to be similar to that with temperate grasses.
Day length, rainfall, temperature, humidity, and radiation level may
influence seed production (Lock, 1980).
Callide rhodesgrass was grown under controlled conditions at night
temperatures of 50, 59, and 680 F, and 770 F daytime (15 hours) temperature.
Callide percentage seed set was 60, 25, and less than 10 for 68, 59, and 50" F,
respectively. As temperatures were reduced, seed germination was not affected
despite the decreasing grain weights (Loch and Butler, 1987).
Table 5. Effect of season and length of regrowth on feeding value of chaffed
rhodesgrass and Pangola hay.
Harvest Regrowth Rhodes Pangola
Date Days DOM+ VI DOM VI
% g/kg W 0.75 % g/kg W 0.75
May# 30 62.7 29.0 68.9 33.8
June 30 66.1 37.1 63.7 29.0
July 30 62.0 29.4 62.2 27.9
Aug. 30 62.6 32.7 66.8 34.7
Sept. 30 63.5 30.2 61.9 29.9
July 70 57.5 26.0 57.9 23.7
Aug. 98 49.5 17.1 48.2 18.1
Oct. 42 60.2 26.5 61.5 26.9
Nov. 70 53.8 21.7 58.4 28.6
Dec. 105 52.9 20.9 58.0 28.5
+ Digestible organic matter
+ Voluntary intake
# = November in Australia
Seed formation and production of rhodesgrass seeds depend on the ecotype.
Seed formation in the right genotype can approach 90% of the potential; and 100
to 200 Ib/a of clean seed, testing 75% germination, also is possible (Bogdan,
1969). The Rhodesian seed testing laboratory, utilizing numerous samples,
found that Callide had an average of 41% pure live seed (pure live seed content
= pure seed % X germination %)(Hanssen, 1975). Seed yields are increased up to
a maximum with increasing rates of nitrogen applied.
It is particularly difficult to clean (remove glumes and awns) Callide
rhodesgrass seeds, although it has been suggested that a hammer mill operated
at 2450 rpm will do an adequate job (Lancaster, 1949). At the ARECFP, a hammer
mill has been used successfully to obtain pure grains, however, it may not be
economical to do this on a commercial scale because of increased costs. In
Australia, seed is sold as "direct combined". This is a fluffy combination of
grains, glumes, awns, and stem portions. The bulk density of this mixture is
very low. Because of the contaminants, sometimes it is hard to meet the 20%
purity required by the Australian seed industry for commercial seed. In a
harvest in Florida, direct combining was easily done and the resulting
harvested material was not unlike that from the original Australian imported
seed. The percentage seed in the Florida combined material was 57%, and
germination rate was 86%. Also, because of the fluffiness, the material will
not pass through a cyclone type seeder unaided, nor through a grain drill. It
is necessary to hand-feed the material slowly into a cyclone seeder with a
completely open discharge. A stick should be kept handy in case of "bridging"
of the seed mixture. Florida harvested seeds can be mixed with dry fertilizer
without problems. This is the method that appears most adapted for Callide
0 2 4 6 8 10 12 14 16
REGROWTH AGE, WEEKS
Fig. 5. Effect of regrowth age on
mean In vitro dry matter digestibility
of three rhodesgrasses.
When Callide should be harvested for seed, depends on the average number
of fertile panicles in the field, and how well the spikelets are filled with
cariopses (grain). To determine the "fill", the base of a spikelet should be
squeezed so as to permit the grain (during the seed developmental stage), if
present, to protrude. When the cariopses are plump they are ready for harvest
(Hanssen, 1975). A simpler method is to wait until about 10 to 20% of the
major spikes have shed. Harvesting time for Callide seeds is not very
critical, and harvesting can be spread over a 2 to 3 week period. The seed
will not be ready to harvest for at least 21 days after flowering (Hanssen,
1975). Panicles arise over a period of a month or more, but it is possible to
judge when the major emergence or flush occurs. When panicles from the major
emergence start to shed it will be almost time to harvest in spite of there
being additional panicles emerging. Although Callide requires short daylengths
for flowering in Australia (Cameron, 1967; Loch, 1980), two to three flowerings
can occur in Florida if sufficient time is given for the process to happen.
At the ARECFP 5 weeks after the freeze, and with Callide plants about 18
inches high, panicle emergence had begun. This early panicle emergence is the
result of the short January-February daylengths.
Rhodesgrass is considered to have a moderate phosphorus requirement. The
critical phosphorus level for maximum growth was found to be 0.19 to 0.25% in
the tops and 0.21 to 0.23% in the youngest fully expanded leaf (McIvor, 1984).
In another study (Andrew and Robins, 1971), the critical phosphorus content in
foliage of pre-flowering Pioneer rhodesgrass was 0.22%, with a range of 0.10 to
0.38% with increasing phosphorus levels. Respective Pangola values were 0.16,
and 0.05 to 0.26%. At the critical phosphorus concentration, potassium,
calcium, and magnesium concentrations in Pioneer were 1.14, 0.37, and 0.25%,
and in Pangola, 0.98, 0.17, and 0.36%. Phosphorus deficient Callide leaves
tend to fold inward along the midrib, giving the leaves a long and narrow
appearance (Smith, 1973). Lower leaf tips first show a bronzing coloration,
and progressively turn to an orange-yellow and then to a pale-straw color
without any interveinal pattern.
Rhodesgrass responded to a single application of 380 lb/a of nitrogen
(Dovrat, 1966). Potassium decreased from 0.64 to 0.47% in the foliage as
nitrogen rates were increased to 380 lb/a. The low (0.47%) potassium content
in the foliage did not affect grass growth at the 380 lb/a nitrogen rate
Rhodesgrasses tolerate high salinity (Bogdan, 1969). The salt glands
found on leaves which remove excess salt, particularly sodium, from plants may
be responsible for this tolerance (Liphschitz, et al., 1974). Rhodesgrass
(probably Pioneer) yields were about 5, 7, 4.5, and 4 tons/a from plots
receiving 900, 1500, 3000, and 4500 ppm, respectively, of equivalent quantities
of sodium and calcium chlorides in irrigation water (Gousman, et al., 1954).
Genotypes vary in their uptake of salt. Of 10 entries, sodium content ranged
from 0.50 to 0.70, with Callide having the lowest value (Ando, et al., 1985).
In another test, Pioneer and Callide had respective sodium contents of 1.61 and
0.44% (Playne, 1970).
Seeding Rate. With the quality of seed available in Florida (grain,
glumes, and awns mixtures), at least 10 lb/a of the mixture should be used. IF
cleaned seed (grain only) becomes available in the future, then 3 to 5 lb/a
would be sufficient.
Virgin Land. Since there would not be any serious weed problems, seed
should be broadcast seeded and rolled into a freshly prepared seed bed.
Renovated Old Land. Water sedge and numerous other annual weeds can be
expected to compete strongly with rhodesgrass. A nurse crop, such as millet or
sorghum-sudangrass hybrid at 1/3 to 1/2 the normal recommended seeding rates,
should be seeded with a drill or broadcast when the Callide is broadcast
seeded. The nurse crop should be cut or grazed when it reaches 30 to 36 inches
high to permit development of the rhodesgrass. The use of Tifleaf millet as
the nurse crop was used successfully at the Sartori dairy. After two silage
harvests of the millet, a successful third harvest consisted mostly of Callide
Because it is a seeded grass, no pre-emergence grass herbicides can be
used. However, Callide is not damaged by 2,4-D or weedmaster. Both can be used
for broadleaf weed control after the grass establishes. Weedmaster does an
excellent job killing sedges, even after a month or so after their germination.
Renovation of Old Pastures. Because Callide can be seeded, it provides an
option for renovating poor stands of pasture grasses, substituting a vigorous
grass for a non-vigorous grass, or eliminating high populations of smutgrass or
other weeds. Once germination occurs, and if there is good soil fertility,
Callide seedling growth is rapid. Pasture establishment would be faster than
with vegetatively planted grasses, and much faster than with the bahiagrasses.
In the Virgin Islands, rhodesgrass utilization of nitrogen and yields
responded better to fertilizer nitrogen than did Coastal bermudagrass,
stargrass, and Pangola (Oakes and Skov, 1962).
For establishment in Florida on virgin flatwoods soils, about 400 lb/a of
12-12-12 or similar fertilizer should be applied as soon as seedlings emerge.
Additional nitrogen should be applied after the first (light) grazing if this
occurs before September.
If soil phosphorus is less than 10 ppm on old renovated fields or
pastures, the virgin soil fertilization regime should be used. If soil
phosphorus is higher, then the virgin soil phosphorus rate should be halved.
An established Callide pasture needs to be fertilized a minimum of once a
year with a minimum of 50 to 75 lb/a of nitrogen, and potash at 1/2, and
phosphorus at 1/3 to 1/4 the nitrogen rate. A 16-4-8 or similar fertilizer
would be adequate. A good management scheme with a single annual fertilization
would be to fertilize the Callide in September and begin to graze 6 to 8 weeks
For silage or greenchop, cut 4 to 5 times a year, 75 to 125 lb/a of
nitrogen should be applied after each cut as a 16-4-8 or similar fertilizer.
The higher the nitrogen rate, the higher the forage crude protein level at
a given regrowth interval. When the regrowth interval increases, there is a
concomitant decrease in the crude protein content at a given nitrogen rate.
One spring and one fall hay crop can be made during most years. For
spring, the fertilizer should be applied about the first of March, for harvest
before the rainy season. For fall, apply the fertilizer sometime in September.
The rate and formula used for silage would be adequate.
INSECTS AND DISEASES
Insects. It is assumed that army worms will attack Callide as they do
other vigorous grasses in the late sumner and early fall. Neither the yellow
sugarcane or other aphids have been noted damaging rhodesgrasses at the ARECFP,
even when Pangola and other grasses growing in the same area of small plots
were badly affected. This permits maximum fall growth rate of rhodesgrass
limited only by short day length and low temperatures, rather than by those
factors plus aphids as with Pangola.
Rhodesgrass scale was first found in Texas in 1942 (Schuster, et al.,
1969) and had been observed at the ARECFP on rhodesgrass in an area where
Pangola also was infested. Also, it attacked naturalized paragrass and other
grasses in the area. Since scale parasites were released in south Florida in
the 1960's, there have been no major outbreaks of the scale reported, and the
author has not seen any scale on any of the improved pasture species for 15
years. Parasites have been very successful in controlling the pest in Texas
The lesser corn stalk borer may be the worst insect pest of rhodesgrasses.
Also, it attacks other seeded grasses and legumes. This insect is difficult to
detect until damage has been done. The small caterpillar lives on or near the
soil surface in a woven-web tube that protects it from rain (and insecticides).
The tube is attached to the seedling plant at or near the soil surface where
the insect can damage or kill the seedlings by feeding on the stem at ground
level. Insect buildup normally occurs when the weather is dry and warm, and
can become particularly bad in late spring in soils which are dry down to
several inches; however, during dry spells in the summer through early fall,
the borer also can be very active. Entire stands of seedlings 2 to 4 inches
high can be killed if conditions are optimum. Existing insect populations can
be expected to decrease with heavy rainfall and high soil moisture. After sane
point during grass maturation, plants may be damaged but not killed.
Spittle Bug. It is believed that spittle bug damage to rhodesgrass would
be less than that on limpograss and Pangola because of its more erect growth,
less lodging, and more air circulation near the soil surface. However,
observations should be made for spittle masses or adults during high rainfall
summer periods when grass has not been grazed or cut for 6 to 8 weeks.
Mole crickets in Africa have damaged seedlings, and thrips have damaged
ripening seeds in Texas. Insecticides were effective in control of both
insects (Bogdan, 1969).
Diseases. Helminthosporium hawaiiense, causing leaf and culm striping,
was first reported in the United States at the ARECFP by Sonoda in 1974. H.
madi was found to cause striping of rhodesgrass foliage in India (Prakash,
1976). Fusarium graminearum in Kenya attacked spikelets and caused serious
seed losses; and F. oxysporum was reported on rhodesgrass in Israel (Bogdan,
1969). It is believed that much of the most serious foliage damage by diseases
can be effectively controlled through proper grazing or cutting management.
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