Bromus inermis Leyss.
Syn.: Zerna inermis (Leyss.) Lindm.
Bromus glabrescens Honda
Bromus tatewakii Honda
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
One of the best hay and pasture grasses, grown extensively in United States,
Europe, Russia and Argentina. Often grown for long-term leys. Equal to any
forage grass in areas where it is adapted because of high palatability and
yield. Excellent for soil erosion because of the interlocking root system.
Especially valuable in semi-arid regions, as the Prairie Provinces of Canada
and the Great Plains of the United States. (Reed, 1976)
Tests for antibacterial activity against Mycobacterium tuberculosis have
proved negative, and positive (Watt and Breyer-Brandwijk, 1962).
On a zero-moisture basis, smooth brome (moisture content 4.2 to 16.8%, mean of
215 cases = 10.3) contains 3.0 to 27.9 g crude protein (mean of 245 cases =
12.3), 1.2 to 6.8 g fat (mean of 238 cases = 2.6), 16.3 to 46.0 g crude fiber
(mean of 240 cases = 31.7), 4.6 to 12.4 g ash (mean of 244 cases = 8.8), and
34.1 to 52.2 g N-free extract (mean of 245 cases = 44.6), 210 to 980 mg Ca
(mean of 125 cases = 430), 40 to 740 mg P (mean of 126 cases = 280), 2.8 to
10.1 mg Cu mean of 32 cases = 5.2), 1470 to 3500 mg K (mean of 104 cases 2360),
80 to 420 mg Mg (mean of 103 cases = 210), 4 to 34 mg Fe (mean of 88 cases =
10), 16.0 to 21.3 mg niacin (mean of 7 cases = 18.6), 167 to 332 mg choline
(mean of 5 cases 251), and 1.0 to 84.0 mg carotene (mean of 26 cases 16.7)
The species may become ergotized with Claviceps, hence becoming very dangerous.
Long-lived, sod-forming perennial, spreading by creeping rhizomes, leafy; culms
erect, 60120 cm tall, glabrous; basal and stem leaves numerous; leaf-blades
usually 1015 cm long, sometimes up to 55 cm long, 38 mm broad, or up to 1.3
cm broad, nearly flat, somewhat firm; ligules less than 2 mm long, truncate;
panicles narrow, the erect branches ascending or spreading in flower, 1020 cm
long, rather dense, branches subverticillate, short; spikelets 2.5 cm long,
narrowly oblong, pale green to slightly purple-tinged, 68-flowered; lemmas
mucronate or short-awned, narrowly oblong, about 10 mm long, membranous,
obtuse, with 2 minute teeth, the awn wanting or to 1 mm long between the teeth;
glumes acute, the lower 45 mm long, the upper 67 mm long; anthers linear,
orange-yellow, 45 mm long. Seed 299,880 to 300,000/kg.
About 34 cvs are classified as northern and southern. The Northern strains,
derived from Siberian introductions, adapted to conditions in adjacent Canada
and the northern Plains of United States include: 'Mancharl, 'Parkland',
'Martin', 'Canadian Certified', 'Wiley', 'Chapple No. 14', and 'Mandon 404';
these bunch more than southern strains, do not become sod-bound so rapidly, and
are less productive in southern areas. Southern strains, derived from
Hungarian introductions, adapted to cornbelt areas of Central United States and
as far north as southern Minnesota, include: 'Lincoln', 'Fisher', 'Achenbach',
and 'Elberry'; these are not winter-hardy in northern areas. 'Prior',
developed in Sweden for permanent pastures or long leys on dry soils; in
Germany, 'Von Kanekes', for light soils, 'N.F.G.' for moister, clayey soils.
The genus Bromus contains many complex, polyploid series. Bromus
inermis belongs to section Bromopsis, containing wild species with
chromosome numbers ranging from 2x to 8x. Following its introduction to North
America, smooth broome, an aggressive species, has tended to replace native
American species of sect. Bromopsis, especially B. pumpellianus.
Hybridization studies have been made between: B. inermis, 8x; B.
pumpellianus, 8x; and material of the introduced B. erectus complex
(6x, 8x, 10x, though the last is probably itself hybrid). An objective of
these studies was to incorporate into inermis the larger seeds of
pumpellianus and better seedling vigous of erectus. The three
species are related, crossable and give quite fertile hybrids. Collections
of B. inermis in North America show varying meiotic irregularity and
aneuploidy. This is probably a result of introgression from B. pumpellianus
and the B. erectus complex. Quite a high degree of meiotic
irregularity may be tolerated under natural conditions in a long lived, cross-
pollinated species such as B. inermis, which can spread aggressively by
rhizomes (Borrill, 1976). Reported from the Eurosiberian Center of Diversity,
smooth bromegrass or cvs thereof is reported to tolerate alkali, disease,
drought, frost, fungi, grazing, heavy soil, high pH, mycobacteria, salt,
viruses, and weeds. (2n = 28, 42, 56) (Duke, 1978).
Native to Central and Northern Europe and temperate Asia, extending to China.
Introduced to United States and Canada in 1880 from Hungary and in 1896 from
Russia. Now widely distributed to Argentina and elsewhere.
Best adapted to regions with moderate rainfall and moderate cool summer
temperatures. Suited to silt or clay soils, deep loams, but also does well on
light sandy soils, on well-drained soils. Less drought resistant than crested
wheatgrass, but does not tolerate temperature extremes. Also suited for
irrigated areas. Not recommended for saline or alkali soils. Ranging from
Boreal Moist to Rain through Subtropical Dry Forest Life Zones, smooth brome is
reported to tolerate annual precipitation of 3.2 to 17.6 dm (mean of 46 cases =
7.2), annual temperature of 4.3 to 19.9°C (mean of 46 cases = 8.8),
and pH of 4.9 to 8.2 (mean of 40 cases = 6.4) (Duke, 1978, 1979).
Propagated from seed. Seedbed should be firm and seed should not be covered to
more than 613 mm depth. When grown for hay, seed 1116 kg/ha with 47 kg/ha
alfalfa; for pasture, 11.5 kg/ha of Ladino or White Dutch clover should be
seeded with the bromegrass and the alfalfa. When grown for seed in irrigated
areas, smooth bromegrass is planted in rows 75100 cm apart and seeded at 3.3
kg/ha. This grass rapidly becomes sod-bound if sown pure, and is nearly always
sown in mixtures with alfalfa, sweet clover, red clover or Lotus corniculatus.
Growth starts early in spring with a further period of growth in early autumn
under favorable moisture conditions. Prior to planting, broadcast and plow
down up to 220 kg/ha of P2O5 based on soil needs. At planting apply 55 kg/ha
of nitrogen plus up to 55 kg/ha phosphate, based on soil needs. Established
stands of bromegrass for hay or pasture should be fertilized with 55 to 110
kg/ha of nitrogen in early spring and another 55 to 110 kg/ha at midseason.
For seed production, 83 to 110 kg/ha of nitrogen should be applied in September
and again in the spring. Nitrogen fertilization is required for optimum hay,
pasture or seed yields in most areas. Plants spread rapidly from rhizomes.
Bromegrass is long-lived if irrigated, fertilized and harvested properly. It
provides palatable pasture and hay if not too mature. It resists over-grazing
and trampling, but will not persist under close grazing. It should be managed
so that 1520 cm of grass are always left on pasture. Old, unproductive,
sod-bound swards may be improved by heavy disking and overseeding with a legume
or by applying nitrogenous fertilizer in spring. In some areas, such as
Kansas, it becomes sod-bound just a few years after planting. This condition
can be corrected by applying sufficient nitrogen each year and grazing it
moderately. Properly managed stands can be maintained almost indefinitely.
Smooth bromegrass is said to produce consistently about 12.5 T/ha (Reed, 1976).
Pasture trails with this grass have shown that about 1.5 T/ha of beef can be
obtained. Seeds mature in late summer when plants are 93123 cm tall. Seed
yields of 1.5 T/ha are obtained when irrigated. Knowles et al, (1978) however,
report yields closer to 2.5 MT with 2 cuts 'Carlton' per year at Saskatoon, 8.5
MT with 4 cuts. At Lacombe, Canada, with 506 cuts per year, 'Carlton' and
'Manchar' yielded ca 17 MT, 'Magna' closer to 18. This is the most widely
utilized of the cultivated bromegrasses, being both highly palatable and
nutritious in regions of adaptability. Used for hay, pasture and ensilage in
northern states east to North Dakota, in Pacific Northwest and in Intermontane
area of West; as a meadow grass in northeastern United States; as important hay
grass in Hungary, Ukraine and temperate Asia, and for long-term leys in western
According to the phytomass files (Duke, 1981b), annual productivity ranges from
1 to 11 MT/ha (13 in Canada, 2 in Egypt, 211 in USSR). Hay yields of 12.5
MT/ha are reported (Duke, 1978). Bromus tectorum DM yields range from
ca 18 MT/ha, B. unioloides gives 8 in Australia, 416 in France, 13 in
Jamaica, 1314 in Poland, 67 in the US (Duke, 1981b).
Following fungi have been reported on smooth bromegrass: Alternaria tenuis,
Ascochyta graminicola var. diedickeana and var. holci, A. sorghi,
Cercospora festucae, Cercosporella herpotrichoides, Claviceps purpurea,
Colletotrichum graminicola, Curvularia geniculata, Epichloe typhina, Erysiphe
graminis, Fusarium acuminatum, F. culmorum, F. equiseti, F. graminearum, F.
oxysporum, F. scirpi, F. poae, F. solani, Gloesporium bolleyi, Helminthosporium
bromi, H. leersii, H. sativum, H. giganteum, H. sorokinianum, Ophiobolus
graminis, Ovularia pulchella var. agropyri, 0. pusilla, Pellicularia
filamentosa, Pyrenochaeta terrestris, Pyrenophora bromi, Phyllachora graminis
Puccinia bromina, P. coronifera, P. coronata, P. dispersa, P. graminis, P.
rubigo-vera, Pythium arrhenomanes var. canadense, P. debaryanum, P.
graminicola, P. irregulare, P. ultimum, P. vexans, Rhizoctonia solani,
Rhyncosporium secalis, Sclerophthora macrospora, Sclerotinia borealis, Septoria
bromigena, S. bromi, S. affinis, Scolecotrichum graminis, Selenophoma
bromigena, Stagonospora bromi, Thanate cucumeris, Trichometasphaeria
taminensis, Urocystis bromi, Ustilago bromina, U. bromivora, U. bullata, U.
macrospora, U. striiformis. Bacterial diseases are caused by the following
agents: Pseudomonas coronafaciens var. atropurpurea and
Xanthomonas translucens var. cerealis and var. undulosum.
Virus diseases include: Brome mosaic and Marmor graminis virus. Nematodes
isolated from Smooth bromegrass include: Ditylenchus dipsaci,
Helicotylenchus pseudorobustus, Heterodera avenae, Meloidogyne arenaria, M.
hapla, M. incognita acrita, M. javanica, Paratylenchus projectus, Pratylenchus
penetrans, and P. pratensis (Golden, p.c., 1984). Bank's grass mite
has been a problem when this grass is grown from seed in some parts of Nevada.
Complete list of references for Duke, Handbook of Energy Crops
- Borrill, 1976
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 161. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
- Duke, J.A. 1979. Ecosystematic data on economic plants. Quart. J. Crude Drug
Duke, J.A. 1981b. The gene revolution. Paper 1. p. 89150. In: Office of
Technology Assessment, Background papers for innovative biological technologies
for lesser developed countries. USGPO. Washington.
- Miller, D.F. 1958. Composition of cereal grains and forages. National Academy
of Sciences, National Research Council, Washington, DC. Publ. 585.
- Reed, C.F. 1976. Information summaries on 1000 economic plants. Typescripts
submitted to the USDA.
- Watt, J.M. and Breyer-Brandwijk, M.G. 1962. The medicinal and poisonous plants
of southern and eastern Africa. 2nd ed. E.&S. Livingstone, Ltd., Edinburgh
Last update Tuesday, December 30, 1997