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Sudan grass

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Sudan grass is a fodder crop related to annual cereal (bluegrass) grasses.

Other names: Sudanese, Sudanese sorghum, Sorochinsky millet.

Sudan grass (Sorghum sudanense)
Sudan grass (Sorghum sudanense)
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©MarkusHagenlocher (CC BY-SA 3.0)

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Economic importance

Sudann grass is one of the most important crops used for fodder purposes in the steppe zone of Russia, where it gives the highest yields of hay and green mass compared to other annual fodder crops.

It is used for green fodder, for grazing livestock, forage harvesting for the winter. It is also grown as a subsow crop for winter crops, corn, peas for green fodder, etc. After harvesting the cover crop, it allows an additional 1-3 cuttings, depending on the zone. So, in the green conveyor system in the forest-steppe zone, Sudanese grass is sown in a mixture with corn, while in the first cut, the crop is formed mainly due to corn, and aftermath – due to Sudanese grass. The usual row sowing of this mixture makes it possible to obtain, with natural moisture, up to 35 t/ha of green mass, while sowing only one corn – 18 t/ha. Sowings of a mixture of Sudanese grass with annual leguminous grasses are being introduced.

Sudan Grass withstands grazing well and is resistant to trampling. After mowing and grazing on the vine, it grows well. Under favorable conditions, with natural moisture in the forest-steppe zone, it can produce 2-3 cuttings over the summer, and with irrigation in the steppe zone – 4-5 cuttings.

Also, undersowing of Sudanese grass under the cover of vetch-oat mixture and its post-cutting crops after winter and annual grasses for green fodder give high efficiency.

Sudan grass hay contains 9-10% protein, up to 16% sugars. The content of carotene in the green mass is 65-80 mg/kg. Protein digestibility coefficient – 60.8%, fat – 45.7%, nitrogen-free extractives – 73.4%, fiber – 69.1%. Due to the high content of sugars, it is well eaten by animals. In terms of protein content in green mass and hay, Sudanese grass is superior to other cereal grasses.

100 kg of green mass contains 19.0 feed units and 2.3 kg of digestible protein. 100 kg of hay – 52.0 feed units and 6.5 kg of digestible protein. Depending on the vegetation phase, 1 feed unit contains 110-136 g of digestible protein, which corresponds to zootechnical standards. The nutritional value of the fodder mass can be increased when grown in mixtures with annual legumes.

Sorghum-Sudanese hybrids are characterized by high yield (up to 50-60 t/ha of green mass), high drought resistance and aftertaste. In Moldova, after stubble sowing of sorghum-Sudanka hybrid Rostovsky 3 against the background of nitrogen fertilizers (N60-120), the yield of green mass reached 39.2 t/ha.

Cultural history

It comes from Sudan (Africa), where it grows in natural phytocenoses.

This culture was brought to Russia at the beginning of the 20th century. The first experiments on the cultivation of Sudanese grass were carried out in 1914 at the former Yekaterinoslav Experimental Station.

Cultivation areas

It has become widespread in the steppe and forest-steppe zones of Russia: in the Kuban, Don, Stavropol, arid regions of the North Caucasus, the Lower and Middle Volga regions, and the Central Black Earth zone. It is also cultivated in Bashkortostan, Tatarstan, Siberia, the central regions of the Non-Chernozem zone.

Yield

With a high level of agricultural technology, Sudan grass allows you to get 5-10 t/ha of hay, 35-40 t/ha of green mass. On dark chestnut soils during irrigation, it was possible to annually obtain 37.9 t/ha of green mass (Engelssky state farm, Saratov region).

In stubble crops, the yield of green mass during irrigation is 20.5-38.0 t/ha (Volgograd Agricultural Institute). Joint sowings of Sudanese grass and sowing rank yielded an average of 26 t/ha of green mass over 3 years. In the experiments of the Research Institute of Agriculture of the Central Chernozem belt, when sowing Sudanese grass after intermediate winter crops, the average yield of green mass over 3 years was 15.8 t/ha.

Botanical description

Sudan grass (Sorghum sudanense stapf) is an annual plant in the bluegrass family.

The root system is fibrous, well developed, penetrating the soil to a depth of 2.5-3 m. In the horizontal direction, the roots go 75 cm. Sometimes aerial, or adventitious, roots 6-8 cm long can form from the lower stem nodes.

The stem is cylindrical, hairless, filled with spongy white parenchyma. The height of the stem is 80-300 cm. The number of internodes on the stem depends on the duration of the growing season of the variety. In early-ripening varieties on the main stem, their number is 3-5, late-ripening – 8-12. The lower stem node is the tillering node.

According to the general bushiness, Sudanese grass is divided into:

  • slightly bushy – the number of shoots in the bush is up to 12;
  • medium bushy – 12-25 shoots in a bush;
  • strongly bushy – more than 25 shoots.

According to the shape of the bush, varieties of Sudanese grass are divided into:

  • upright;
  • slightly sprawling;
  • sprawling;
  • reclining;
  • recumbent.

The most common varieties with erect and slightly sprawling bushes. In general, varieties with a dense bush are more productive than varieties with a loose bush.

The leaf is large, consists of a sheath and a leaf blade. The plate is broadly linear, 45-60 cm long, 4-4.5 cm wide, glabrous, smooth, slightly rough along the edge. The leaves of the middle tier are the most developed.

Sudanese grass varieties are divided into groups according to leafiness:

  • with weak foliage, that is, up to 6 leaves on the main stem and up to 35% of the mass of leaves in the total yield;
  • with medium foliage, that is, 6-9 leaves on the main stem 6-9 and 35-50% of the mass of leaves in the total yield;
  • with good foliage, i.e. more than 9 leaves on the main stem and more than 50% of the mass of leaves in the total yield.

The inflorescence is a multi-eared panicle, usually 40 cm long. Spikelets are single-flowered. There are strongly sprawling, sprawling, semi-contracted, compact, drooping and sorghum types of panicles. Spikelets are located at the ends of the panicles.

The fruit is a caryopsis tightly seated in glumes. Unlike sorghum , the top of the grain does not protrude. One panicle gives 4-5 g of seeds. Weight of 1000 seeds 10-15 g.

Biological features

Heat requirements

Sudanese grass belongs to heat-loving and heat-resistant crops. Seeds begin to germinate at a temperature of 8-10 °C, the optimum temperature for germination is 20-30 °C.

The sum of active temperatures for full development, depending on the precocity of the variety, ranges from 2200 to 3000 °C.

Frosts at -3…-4 °C are detrimental to seedlings. Intensive growth of stems occurs at an average daily air temperature of more than 10 °C.

Moisture requirements

Sudanese grass is characterized by high drought resistance, which is due to a powerful developed root system and a long growing season, which allows plants to use the rainfall of the second half of summer.

Plants absorb the most moisture from deep soil horizons. This feature must be taken into account when placing it in crop rotation fields. So, sunflower also absorbs a lot of water from deep layers (more than 1 m), so placing these crops one after another on rain-fed lands is not recommended.

Sudanese grass is responsive to irrigation: it significantly increases the yield of green mass and hay.

Does not tolerate excessive moisture.

Light requirements

Light-loving short day plant. With a long daylight hours, development slows down.

In the germination-tillering phase, Sudanese grass tolerates shading well, so it can be used as a subsowing crop.

Soil requirements

To soils, as well as sorghum-Sudanese hybrid, it is not demanding. Chernozem and dark chestnut soils are well suited, less so are light chestnut, sandy and sandy soils. It can withstand slight acidity, does not grow well on saline, waterlogged and overcompacted soils, as well as in areas with close groundwater.

Plant nutrition

For the formation of 1 ton of dry matter, Sudan grass consumes up to 25-30 kg/ha of nitrogen from the soil (therefore, it is very responsive to nitrogen fertilizers), 6-7 kg/ha P2O5 and 15-17 kg K2O.

Vegetation

During the first 5-6 weeks after sowing, Sudan grass develops very slowly, forming 4-5 leaves. Tillering begins with the formation of the fifth leaf. At the end of the tillering phase and in the subsequent phases of vegetation, an intensive daily growth of plants in height of 5-10 cm is noted.

Stem growth stops at the flowering stage. After mowing or grazing, regrowth occurs from shoots developed from tillering nodes, formed from aboveground stem nodes and growing from cut shoots, with a preserved growth point. Thus, after mowing or grazing, three types of shoots grow back, resulting in high afterburner and the possibility of obtaining a large number of cuttings in one year.

Aftermath productivity depends on the cutting height. Since regrowth occurs in three types (from 2 buds of the tillering node, from the axil of the first internode and from the point of growth), then at a low cut (4-5 cm or less), the first internode is beveled and the number of growing shoots is reduced by 20-25% . When mowing above 7 cm, all types of regrowth are preserved and productivity increases in subsequent mowing. Thus, low mowing under production conditions is often the cause of low yields of Sudan grass.

Ejection of the panicle on the main stems occurs after 6-7 weeks from emergence and lasts 2-3 weeks. Flowering begins at the top of the panicle and ends with the last flowers on the lower branches. Flowers open in the morning. Pollination is anemophilous (by wind).

The growing season is 100-120 days.

Crop rotation

Winter cereals, legumes, row crops, corn, perennial grasses are considered good predecessors in crop rotation for Sudanese grass.

When placing crops after Sudanese grass in a crop rotation, it must be taken into account that it greatly dries up the soil and takes out a large amount of readily available nitrogen. Therefore, melons and gourds are placed in the dry steppe zone after it, the root system of which is able to penetrate the soil to a depth of 10 m.

Fertilizer

Sudan grass is responsive to the introduction of rotted manure , which, at an application rate of 18-20 t/ha, provides an increase in hay yield by 23-26%. It also responds to the aftereffect of manure introduced under the predecessor. For example, applying manure at a rate of 36 t/ha two years before sowing Sudanese grass increased the hay yield by 30-32% (Poltava Agricultural Experimental Station).

Nitrogen fertilizers are the most effective . Thus, the introduction of 45 kg/ha of nitrogen increased the hay yield by 1.3 t/ha (former Kharkov Agricultural Experimental Station).

The introduction of 45 kg/ha P2O5 increases the yield of hay by 22.6% (Drabovskoye experimental field).

Potash fertilizers give good results on sandy soils.

The general recommended application rates for mineral fertilizers for Sudanese grass are N45-50P30-45K30-45. Voronezh Agricultural University for the forest-steppe zone recommends applying N30-45P30-45K20-30 to the main fertilizer, when sowing in rows P10 and to top dressing after mowing N20-30P45K20-30.

Row application of phosphate fertilizers is effective. For example, the introduction of 75 kg/ha of granulated superphosphate into the rows during sowing increased the hay yield by 1.4 t/ha (Erastovskoye experimental field).

Tillage

The tillage for Sudan grass is the same as that recommended for millet.

Due to the slow development at the beginning of the growing season, an important requirement for tillage is the purity of the crops. Therefore, soil cultivation for Sudanese grass should include peeling, deep autumn tillage, early spring harrowing, double pre-sowing cultivation, rolling before and after sowing.

Sowing

The seeding rate in dry steppes and semi-deserts is 10-14 kg/ha, in the forest-steppe – up to 25-30 kg/ha with a rainfall of 500-600 mm per year, with wide-row crops – 8-14 kg/ha.

The seeding rate of seeds of sorghum-Sudanese hybrids is 30-35 kg/ha.

Sowing begins when the soil warms up at a depth of 10 cm to 10-12 °C. Too early sowing leads to a belated and sparse emergence of seedlings, the field is overgrown with weeds .

In the green conveyor, Sudanese grass is sown at several times, with an interval of 10-12 days. Sudanese grass is sown in summer sowing.

The method of sowing when cultivating for fodder is continuous (ordinary row), for seeds – wide-row. In conditions of sufficient moisture, the conventional row method can be used for seed cultivation, while in severely dry conditions, the wide-row method (45-60 cm) can be used for fodder cultivation.

The seeding depth is 2-4 cm, on light soils it is increased – up to 4-8 cm. After sowing, the field is rolled.

Harvest

Harvesting for hay begins at the end of the booting phase – the beginning of panicle ejection at a plant height of 50-60 cm (usually occurs 55-65 days after sowing). Early cutting promotes good regrowth and second cutting. Late mowing results in coarse hay.

The second and third cuttings are carried out with an interval of 30 days. According to the Erastov experimental field, this mode of using Sudanese grass for green mass is the most productive. The mowing height is 7-8 cm, since at a lower height the growth of young shoots slows down and the yield decreases.

For silage, mowing is carried out in the phase of milky ripeness of the grain.

Mixed, mowing and stubble crops

Good results are shown by joint crops of Sudan grass and soybeans, especially in the south of Russia, where there is sufficient rainfall or irrigation is used. The yield of green mass when irrigated with a mixture of Sudanese grass and pelushka in the Novosibirsk region reached 41.5 t/ha (Studenovsky state farm).

In the Poltava region of Ukraine, a mixture of Sudan grass with spring vetch or hairy vetch made it possible to double the collection of protein per unit area in comparison with pure crops.

Joint crops of Sudanese grass with lathyrus, peas and alkaloid- free lupine are also used.

The sowing rate of Sudanese grass in joint crops is reduced by 15-20% compared to the sowing rate in its pure form.

In the south, good yields are obtained with the stubble crop of Sudanese grass after harvesting barley, wheat, peas for grain, in the forest-steppe zone – post-cut crops after harvesting winter rye, vetch-oat, lathyrus-oat mixtures for green fodder or hay.

Soil cultivation for stubble crops should be carried out immediately after harvesting the main crop. With sufficient moisture, the soil is plowed to a depth of 20-25 cm with simultaneous harrowing. When the top layer of soil is dry, first plowing is carried out, then deep plowing with harrowing and soil compaction before sowing.

The rate of stubble sowing is increased by 20%.

Growing for seeds

For seed purposes, Sudanese grass is best placed in the tilled field of a field crop rotation.

In arid regions, it is sown for seeds in a wide-row way, the row spacing is 45-50 cm, at the optimum time, vegetable seeders are well suited. Seeding rate 12-15 kg/ra.

Herbicides are used to control weeds. On wide-row crops, 2-3 inter-row treatments are carried out.

Seeds ripen unevenly, usually 100-130 days after sowing. Seed harvesting begins when the main stem panicle matures, when the seeds become hard, by direct combining. With a high stem, first panicles and part of the stems are removed on a high cut, then the remaining mass is mowed with mowing machines. For mowing panicles, the CM-2.6 machine is also used, which removes only panicles of Sudanese grass, sorghum-Sudanese hybrids and sorghum. Seeds are immediately cleaned of impurities and dried.

Separate cleaning is also possible. The method of harvesting depends on weather conditions and infestation of crops.

Sources

Crop production / P.P. Vavilov, V.V. Gritsenko, V.S. Kuznetsov and others; Ed. P.P. Vavilov. – 5th ed., revised. and additional – M.: Agropromizdat, 1986. – 512 p.: ill. – (Textbook and textbooks for higher educational institutions).

V.V. Kolomeichenko. Crop production / Textbook. — M.: Agrobusinesscenter, 2007. — 600 p. ISBN 978-5-902792-11-6.

Fundamentals of agricultural production technology. Agriculture and crop production. Ed. V.S. Niklyaev. – M .: “Epic”, 2000. – 555 p.