Economic importance, morphology and history of sorghum cultivation

Sorghum is a valuable food and forage crop for regions where wheat and other main grain crops cannot grow or produce low yields due to an arid climate. Sorghum grain is used to produce groats and flour; furthermore, it is a valuable feed for livestock and poultry, as well as a raw material for the compound feed, starch-syrup, and alcohol industries.

Sorghum grain is round or slightly ovoid, without a furrow, naked or covered (in glumes and paleae). The main characteristics of the grain are:

Grain with a brownish or reddish endosperm contains astringent tannins of the tannin group.

Sorghum is a valuable forage and, in part, food crop. Its agricultural use:

• Grain — feed for pigs, cattle, horses, and poultry, as well as a raw material for compound feed.
• Green mass — good feed for dairy cattle and growing young stock.
• Silage — similar in quality to corn.
• Hay (when mown before the stem becomes coarse) — little different from Sudan grass hay; it is particularly valuable when sown in a mixture with soybeans or lablab.
• Pasture use — regrows well after cutting.

A valuable quality of sorghum is that its leaves and stems retain their green color and succulence during full grain ripeness, which allows them to be used for silage. The green mass of sorghum sometimes contains a toxic substance — dhurrin (a glucoside), which turns into hydrocyanic acid upon hydrolysis (most often during drought).

Common sorghum (Sorghum vulgare Pers.) has been used since ancient times. Equatorial Africa is considered the cradle of sorghum, where it remains (as in many other African countries) a staple cereal crop; the greatest number of its varieties are concentrated here. Sorghum cultivation was known as early as 3000 BC in India and China (where the second group of 205 sorghum is called "jowar" or "golan").

In Central Asia, its cultivation also dates back at least 2500—3000 years. It has been known in Italy since the 15th century. In Russia, in the region of Uralsk (Yaitsky Gorodok), sorghum has been cultivated since the 17th century. The first sorghum sowings for feed were made in the south of Ukraine (near Kherson) in 1890, later — in the North Caucasus and the Lower Volga region. Sorghum is widely cultivated in the arid states of the USA (Texas, Kansas, etc.). The global area of sorghum is about 28.6 million hectares. Its largest sown areas are in India, China, and Africa.

Fig. 23. Sorghum: morphological features of the plant (a); sorghum forms large spreading panicles (b, c); sorghum with a compact panicle form (d); caryopses (e)

Among the diversity of sorghum species, common sorghum (Andropogon sorghum Brot., or Sorghum vulgare Pers.) and Sudan grass (Andropogon sudanensis Piper) are of primary importance for the CIS.

The following species have become the most widespread:

• Guinea sorghum (Sorghum guineense Stapf.);
• Kaffir sorghum (S. caffrorum Beauv.);
• Durra (S. durra Forsk.);
• Jugar, Central Asian millet (S. cernuum Host.);
• Gaoliang, Chinese millet (S. chinense Jakushev), and others.

Based on the character of the panicle and the density of the arrangement of branches of different orders, three forms of sorghum can be distinguished:

• spreading (paniculate) sorghum — ssp. effusum Korn. — with a loose, elongated panicle, with long branches;
• contracted sorghum — ssp. contractum Korn. — with a denser, vertical panicle having short branches;
• compact sorghum — ssp. compactum — with a short, very dense panicle, with a straight or curved axis and very short branches pressed against it.

Grain sorghum also includes milo (majlo) — with a great variety of forms, widely distributed in African countries. The plants are tall with a curved inflorescence and brown coloration; the seeds are large and difficult to thresh.

It is not demanding of the soil and tolerates both heavy and very light soils. According to literature, sorghum is a plant that possesses good salt tolerance. Sorghum is resistant to heat and drought, as well as to hot dry winds and dust haze.

Sorghum leaves do not cease assimilation during such drought and heat when corn leaves already lose turgor and curl up. Sorghum effectively utilizes rain in the second half of summer and early autumn.

Foxtail millet (chumiza) is a grain (cereal) and forage crop. Chumiza groats contain many soluble carbohydrates (polysaccharides), cook quickly, swell well, and are little inferior to common millet in taste. Chumiza grain is a valuable feed for poultry and livestock. In addition to being used for grain, chumiza can be grown for green feed, silage, and hay for making nutritious hay meal. Chumiza hay is readily eaten by horses, cattle, and sheep.

The homeland of foxtail millet is considered to be East Asia, China, and Mongolia, where it has been cultivated since ancient times. It is also sown in India, Afghanistan, Turkey, Italy, and Hungary. In the CIS, foxtail millet has been cultivated since ancient times in Georgia (since the 15th century) and in other parts of the Transcaucasus (gomi), in the Central Second Group 207

Fig. 24. Foxtail millet (a, b) and German millet (c); foxtail millet grain (d) Asian republics (kunak) and in Russia (in the Far East, the North Caucasus, the Volga region, and the Voronezh region).

Foxtail millet — Setaria italica ssp. maxima Alef. (Panicum italicum L.) — in appearance is most similar to German millet — Setaria italica ssp. mocharium Alef. It differs from German millet by its larger leaves and V-lobed panicle (spike).

Foxtail millet is not demanding in terms of cultivation conditions, but is very responsive to improvements in agricultural practices. In terms of heat resistance, drought tolerance, and moisture efficiency, it is close to proso millet. Foxtail millet is sown at the same time as proso millet or slightly earlier. In the field, the crop forms a stem-straw from 50–70 cm to 150–200 cm high with weak tillering.

The leaves of foxtail millet are wide, without auricles, and their number per plant ranges from 10 to 16 (up to 25). The inflorescence is a dense, compressed spike-like panicle (spike), usually of a lobed, less often smooth, cylindrical or spindle-shaped form, tapering or widening towards the apex. One panicle contains from 3–5 to 10 thousand grains. The rounded-oval caryopses are covered with floral glumes (like those of proso and German millet) and can range in color from pale yellow to dark red. Foxtail millet itself is a self-pollinating plant.

Buckwheat: nutritional value, forage and honey-bearing use

Buckwheat belongs to the most important grain crops, the grain of which is distinguished by high digestibility and excellent taste. Its dietary value is determined by a high content of easily digestible proteins, carbohydrates, ash elements (phosphorus, calcium, iron, copper), and vitamins (thiamine, riboflavin, rutin). The fruit composition also includes organic acids (citric, malic, oxalic) and vitamin E, thanks to which the groats can be stored for a long time without loss of quality. In terms of the amino acids lysine and arginine content, buckwheat grain surpasses wheat and rice. From the leaves and flowers of the crop, the medicinal drug rutin is obtained, which is used in the treatment of atherosclerosis, hypertension, and for the removal of radioactive substances from the body.

Since buckwheat protein does not possess gluten properties, its flour is not suitable for traditional bread baking, but is used for baking pancakes, flatbreads, and certain types of cookies. The crop is highly valued as a honey plant, the nectar of which contains 40% sugar. From one hectare of crops, up to 100 kg of dark, aromatic honey can be obtained. Bees also provide cross-pollination, which significantly increases the yield of the buckwheat itself.

• Yield of green mass in 40–50 days — up to 200 centners
• Sowing rate of the mixture per hectare — 150 kg of buckwheat and 140 kg of field pea
• Nutritional value of 100 kg of straw — 30 feed units
• Sugar in nectar — 40 %
• Honey collection per hectare — up to 100 kg

Due to its short growing season, buckwheat is used as a re-sown crop after the loss of winter and early spring crops, as well as in stubble crops and green fallow. The green mass of stubble crops can be ploughed in as green manure. Ash from burning buckwheat straw and husks is rich in nutrients: it contains more than 40% K2O, over 10% P2O5, and up to 19% CaO, which is why it is used as mineral fertilizer and a raw material for producing potash. As of 2005, the area of the crop's cultivation worldwide exceeded 4 million hectares, of which about 2.4 million hectares were in Europe and 0.6 million hectares in China.