Smooth brome

Economic importance

Smooth brome is used in meadow and field forage grass cultivation in the forest-steppe and steppe zones of Russia. In field crop rotations, it can be grown in out-of-rotation fields.

It is used for hay, green fodder, and the establishment of artificial pastures.

100 kg of hay corresponds to 57.2 feed units and contains 5.9 kg of digestible protein. 100 kg of fresh grass — 29.3 feed units and 3.0 kg of digestible protein, respectively.

It is suitable for grassing over eroded sloping lands.

Previously, it was not recommended for field crop rotations, since it was assumed that rhizomes would regrow after ploughing up the sod. Experiments showed that after deep ploughing there is no significant threat to subsequent crops. Thus, smooth brome is suitable for cultivation in forage and field crop rotations, as well as for radical improvement of gullies in mixtures with legumes.

It regrows well after mowing and grazing. It shows the highest yield while maintaining productivity as the stand ages under a single-cut system, when cutting is carried out at the flowering stage.

It is considered a valuable crop for improving floodplain meadows and pastures.

History of cultivation

It was introduced into cultivation in the mid-19th century in Voronezh Governorate.

Regions of cultivation

Due to its high ecological plasticity, it can grow under various conditions, up to the Arctic Circle.

It is cultivated in the northern, northwestern, and central regions of European Russia, Western and Eastern Siberia, and Altai Krai.

Yield

Under favorable cultivation conditions, hay yield is 6–8 t/ha and seed yield is 700–900 kg/ha.

In floodplain meadows, hay yield reaches 5–8 t/ha.

Under irrigation in Kaluga Oblast, a mixture of smooth brome and meadow timothy produced a hay yield of 11.8 t/ha.

Botanical description

The genus includes more than 20 species. In agricultural production, awnless brome, or smooth brome (Bromus inermis, syn. Bromopsis inermis Holub), has become widespread — a perennial grass of the tall-growing type.

The root system is fibrous (rhizomatous), powerful. It can root at the nodes, which leads to the formation of new clumps. Rhizomes are 5–20 cm long and lie at a depth of 8–15 cm, which determines its high winter hardiness. Roots penetrate to a depth of 1–2 m. It leaves a large amount of root residues in the soil.

Stems are erect, smooth, hard, well-leafed, 70–200 cm tall.

Leaves are broadly linear, long, flat, relatively coarse, and rough along the margin.

Inflorescence is a panicle. Flowers are large, gathered into spikelets that form a large panicle. Before flowering, the panicle may be inclined (one-sided); after flowering, it is erect and spreading. Multi-flowered spikelets are located at the ends of the panicle branches.

Fruiting is usually abundant; seeds are large, dark gray, oblong. The caryopsis is tightly enclosed by floral scales. The weight of 1000 seeds is 3–4 g.

Smooth brome has two forms:

• northern, or meadow, distributed in the forest zone;
• southern, or steppe, distributed in the steppe zone.

Both forms occur in the forest-steppe zone.

Biological characteristics

Smooth brome is characterized by high ecological plasticity and adaptability to various external conditions.

Winter hardiness, cold resistance, and drought resistance are good. It can tolerate severe snowless winters and spring frosts.

Smooth brome can withstand flooding for up to 30–45 days.

It grows poorly on acidic, strongly compacted, heavy clay, and waterlogged soils. It can grow on solonetz soils. Permeable soils of floodplain meadows, loamy soils, and soils rich in humus are suitable for cultivation. It does well on slopes and stabilized sands, on floodplain and liman meadows with shallow groundwater, and also under irrigation. It is undemanding to soils.

Loose, permeable sandy loam or loamy chernozems, as well as alluvial soils, are optimal, due to favorable conditions for rhizome development. The subsoil should also preferably be loose.

Vegetation

In the first year of life, when sown under a cover crop, it grows slowly; with coverless sowing and sufficient moisture, it can produce a hay cut by autumn.

In subsequent years, it starts growing early in spring, allowing early green fodder to be obtained. Full development of plants occurs in the 2nd–3rd year of life; in the same period, it is harvested for seed.

The highest hay yields are obtained in the 3rd–6th years of life. It persists in the stand for up to 8–12 years; with fertilizers on floodplain lands, more than 20 years.

Development type: winter-spring.

Tillage

Tillage is similar to that for alfalfa.

Sowing

Smooth brome is usually sown in early spring under a cover crop or without cover. Summer sowing in the second half of July is also possible.

Mixtures of smooth brome with perennial legumes (alfalfa and sainfoin are especially suitable) are sown in early spring under a cover crop of spring cereals by the between-row method.

The seed sowing rate of smooth brome for pure row sowing is 16–20 kg/ha, for wide-row sowing 10–11 kg/ha. When grown for forage in grass mixtures, the sowing rate is 8–12 kg/ha; in mixtures with other rhizomatous grasses, 5–6 kg/ha.

Sowing depth is 3–4 cm.

Seeds have poor flowability, so before sowing they are passed through a vegetable grater with rubber rubbing surfaces. After such treatment, they are suitable for sowing with any seed drill.

When grown for seed, the recommended sowing rate for continuous sowing is 20–25 kg/ha, for wide-row sowing 8–10 kg/ha.

Harvesting

Good hay (especially for horses) is obtained by cutting before flowering, when panicles appear. If cut after flowering, the hay becomes coarse.

For seed, smooth brome is harvested by direct combining at full seed ripeness or by the two-phase method. In the latter case, cutting is carried out at the wax ripeness stage of the seeds. After harvesting, the seeds are cleaned of impurities, dried further, and stored for long-term storage.

Varieties

Morshansky 760 (1955).

Sverdlovsky 38 (1971).

Dedinovsky 3 (1974).

SNIISKh 83 (1996).

Yuzhnouralsky.

Mayak.

Bezenchuksky 9.

Antey.

Langepas (1998). The variety was developed by the Research Institute of Agriculture of the Northern Trans-Urals (Tyumen Oblast).

Yubileyny (2004). Developed at the Bashkir Research Institute of Agriculture.

References

1. Vavilov P. P., Gritsenko V. V., Kuznetsov V. S. et al. (1986). Crop Production. Ed. by Vavilov P. P. 5th ed., revised and enlarged. Moscow: Agropromizdat.
2. Kolomeichenko V. V. (2007). Crop Production/Textbook. Moscow: Agrobiznescentr.
3. Niklyaev V. S. (2000). Fundamentals of Agricultural Production Technology. Agriculture and Crop Production. Moscow: Bylina.