Soybean (Glycine max) is an oilseed and grain legume crop.
Other names: soya, edamame, daizu (Japan), mao duo (China), poot kong (Korea).
Source: commons.wikimedia.org©H. Zell (CC BY-SA 3.0)
Economic importance
As a major source of plant protein and edible oil, soybeans are by far the most important food legume crop in the world. Although soybeans are produced mainly for dry seeds, the widespread use of immature seeds, especially in East Asia, makes soybeans an important vegetable crop.
The chemical composition of the seeds: protein – 30-52% (second only to lupine), fat – 17-27%, carbohydrates – 6-20%, minerals (potassium, phosphorus, calcium), fat-soluble vitamins (C, B, E).
Soy is recommended for dietary nutrition of diabetics. Soybean protein is highly assimilable (3.5-4 times more than grain protein) and water-soluble. Among leguminous crops the composition of essential amino acids is the richest. The main protein of soybean seeds is glycinin, which has the ability to coagulate (curdle) when sour. Soybean protein includes the amino acids lysine 2.7% (wheat protein 0.25%), methionine, tryptophan, which determine the feed value.
Soybean is cultivated for food, fodder and technical purposes.
It is used as butter, margarine, soybean cheese, milk, flour, confectionery, canned food and other products. Soybean seeds are a raw material for the soybean oil industry. Soybean oil refers to low-drying (iodine number 107-137) and is consumed in food after refining. It is also used in the soap, paint, glycerin, linoleum, lubricating oils, gelatin and lecithin industries. Soybean oil accounts for 38% of world production, while sunflower oil accounts for 17%.
For feed purposes, soybean are used in the form of cake, grist and soybean meal. Grist contains 40 percent protein, 1.4 percent fat, and about 30 percent nitrogen-free extractive substances. The cake is also used as an additive in baking, pasta and confectionary products.
Immature soybean seeds are used to make preserves and sauces. In Japan and China, immature seeds in their shells are boiled in salted water or cooked in a pod. The pods themselves are too fibrous to eat.
Previously, soybean were grown for green fodder and for ensilaging mixed with corn. 100 kg of green matter contains 21 feed units and 3.5 kg of protein. Can be used to produce grass meal. 100 kg of hay contains 51 fodder units, 15.4% protein, 5.2% fat, 38.6% carbohydrates, 7.2% minerals, 22.3% fiber.
At present, soybean are mainly grown for seed. Mixed crops of soybean and thermophilic grain crops such as Sudan grass, corn and sorghum are considered promising in feed production.
100 kg of soybean stalks are equal to 32 fodder units and contain 5.3 kg of protein. Soy straw is well eaten by sheep and goats.
100 kg of seeds contain 131-147 fodder units and 27.5-33.8 kg of digestible protein.
In conditions of sufficient moisture due to the yield of green mass up to 25-30 t/ha, foliated varieties can be used as green fertilizer.
History of the crop
Soybean cultivation has an ancient history; it is known that it has been cultivated in China since 2800 BC. According to other data, soy has been cultivated in China for 6,000 years B.C. It has also been cultivated in India, Japan, Korea, Vietnam and Indonesia for a long time. In Asian countries, soy is the main raw material for vegetable protein and oil, and there is a wide variety of ways to eat it. More than 250 dishes are known.
In the late 8th century, soybeans were introduced to Europe.
China introduced soybeans to the Far East.
Soybean was originally a short-day and subtropical plant, but the domestication of soybeans has resulted in numerous breeds and breeders have developed varieties adapted to different latitudes. The ability to grow widely is a major advantage of this crop.
Cultivation areas
Soya is the world’s largest crop of leguminous crops. In 1983 it was cultivated on 52 million hectares in more than 40 countries. By the end of the 20th century, it was 67 million hectares, or 42% of the legume-crops cultivated area. The gross harvest is 143 million tons or 62% of the total legume grain harvest at an average yield of 2.2 t/ha.
The United States, Brazil and China are the largest producers. In 1994, the U.S. produced about 50% of world production, 136 million tons, Brazil about 25 million tons, and China about 16 million tons. The U.S. planted 27 million hectares and China 8 million hectares. Major soybean producers also include Japan, Vietnam, Korea, Europe, North Africa, North and South America (Brazil), and Australia.
In the USSR, soybean was introduced into production in 1927. In 1983 it was 890 thousand hectares. The main cultivation regions are the Primorskii and Khabarovsk krais, the Amur oblast, where about 95 % of all soybean areas in Russia are sown. Modern early-ripening varieties are also grown in areas with sufficient moisture in the North Caucasus, Volga region, Central Black Earth zone, Altai, forest-steppe of Ukraine, Transcaucasia, Central Asia and Moldova.
In 2001-2005 in Russia the area of soybean crops amounted to 500 thousand hectares or 29% of grain legume crops. The gross output is 400 thousand tons or 18% of the total legume yield at an average yield of 1.0 t/ha.
Yields
In rainfed conditions of Russia, the yield of soybean seeds is 1.0-1.5 t/ha, in irrigated lands 2.7-4.0 t/ha. With a high level of agrotechnics, soybeans can give higher yields.
In Tambovsky district of the Amur region (state farm “Partizan”), the average yield over several years was 1.2-1.45 t/ha on about 7000 ha. In Belotserkovsky area of Kyiv region (experimental farm “Terezino”, Ukraine) for 15 years on average 1.8-2.0 t/ha of seed, in Tsarichansk district of Kyiv region (state farm “Progress”) – up to 3.06 t/ha from an area of 22 ha.
Yield of advanced enterprises of the Far East and Krasnodar Territory is 2-2,5 t/ha, under irrigation – 3-4 t/ha, green mass – 15-20 t/ha.
Botanical description
Cultivated soybean (Glycine max (L.) Merr., obsolete. syn. Glycine hispida Maxim.) is an annual plant of the legume family (Fabaceae).
Wild forms of Glycine max have not been found. G. soya is an annual occurring in eastern China that hybridizes with G. max and may be a wild ancestor. Another thought is that G. max may be a cultivar derived from hybridization of G. ussuriensis with G. tomentosa; both species occur wild in eastern Asia and southern China. Undoubtedly, the plant is of East Asian origin and domesticated.
Its root system is taprooted, penetrating into the soil up to 1.5-2 m deep.
The stem is strong, erect, strongly branched, not lazy, pubescent, forms a bush of height from 45 to 150 cm.
Leaves are alternate, trifoliate, usually fall off by the time of harvesting.
Its inflorescence consists of a cluster of 3-8 flowers.
Flowers are small, white or light purple, set in axils of leaves in groups of 3-5 flowers. Self-pollination predominates, due to closed flowering natural hybrids are rare.
Pods are variously shaped and colored, contain 1-5 seeds, and usually do not crack. The pods of oilseed varieties usually contain one or two seeds; pods of vegetable varieties usually contain two or three seeds.
Stems, leaves, and pods are covered with dense, tough whitish or red hairs.
The seeds are round, oval or oblong-flat, yellow, green, brown or black depending on the variety. A thousand seeds weigh 100-400 g.
Usage as a food usually correlates with the color of the seeds. Green and yellow-green seeds are produced mainly for vegetables (edible seeds). Large yellow seeds are used to make tofu (bean cake). Large black seeds are used in dishes for celebrations or other special occasions, and small flat black seeds are used to make a spicy fermented side dish. Generally, varieties with yellow seeds are rich in oil and relatively low in protein, whereas varieties with black seeds are high in protein and low in oil. Depending on the type of seed, the carbohydrate content can range from 15% to 25%, the protein content up to 50%, and some varieties contain up to 25% oil.
Biological features
Temperature requirements
Soybean are heat-loving plants. The sum of active temperatures for normal development and ripening depends on the variety and is 1700-3200 °C. The optimal temperature is 20-25 °C. A temperature of 12 to 20°C is sufficient for most growth processes, but delays germination and seed emergence, as well as flowering and seed development.
A temperaturas superiores a 30°C, la fotorrespiración anula la mejora de la fotosíntesis.
The minimum temperature for seed germination is 6-8 °C, and the optimum temperature is 12-14 °C. Sprouts can survive frosts as low as -2 … -3 °C.
The greatest need for heat occurs during flowering and ripening of beans, the optimal temperature in this period is 18-20 °C.
Moisture requirements
Closely related to moisture-loving crops. Due to the slow growth of the above-ground part and a strong root system, soybean tolerates the lack of moisture well in the first period of development. But it suffers a lot from water shortage during flowering and seed ripening.
Its transpiration coefficient is 600.
The period of maximum water consumption is flowering, bean formation, seed ripening.
Light requirements
Soybean is a short-daylight plant. Short-ripening varieties react little to lengthening of daylight hours.
Soil requirements
Soybean can grow on a variety of soils, with the exception of acidic, highly saline, waterlogged, heavy and very light soils. Loamy and sandy loamy chernozem soils and well-drained, light and medium soils are optimum.
Optimal soil acidity is 6.5-7. It yields high yields only on rich in organic matter fertile soils with a neutral reaction.
Soybean is sensitive to saline conditions.
Vegetation
The growing season is 80 to 170 days.
The flowering pattern varies from strongly indeterminant to strongly determinant. The onset of flowering depends on the cultivar and can vary from 80 to 150 days. Flowering time varies from 15 to 40 days depending on the cultivar, with late cultivars having flowering times of up to 80 days.
Vegetation phases:
- sprouts;
- first true leaf;
- branching;
- flowering;
- fruiting;
- ripening.
Crop rotation
Main article: Leguminous crops of the crop rotation
In crop rotations it has an important agrotechnical importance as a leguminous crop with nitrogen fixation ability. It is a predecessor of spring cereals, sugar beets, potatoes, and winter crops in areas with insufficient moisture.
In the rotation, soybean are placed after fertilized crops. In the European part of Russia, winter wheat, corn, and sugar beets may be used as predecessors. In the Far East – seeded fallow, perennial grasses and one year after them.
Other leguminous crops and sunflower because of common diseases are bad predecessors.
In the Far East, soybeans occupy up to 50% of the sown area. According to the All-Russian Soybean Research Institute, the optimal saturation of a crop rotation is 40%, while at 50% the seed yield decreases.
Fertilizer system
For the formation of 1 ton of seeds and the corresponding amount of straw, soybean consume 80-90 kg of nitrogen, 35-40 kg of phosphorus, 60-65 kg of potassium, 70-80 kg of calcium.
Soybean is responsive to phosphorus fertilizers. It is able to absorb phosphorus from hardly soluble phosphates.
Due to nitrogen fixation, soybean can accumulate up to 100 kg/ha of nitrogen, so it covers 30-60% of the nitrogen requirement. However, additional nitrogen fertilizer is needed at the beginning of growth and development.
On low-humus soils, unlike other leguminous crops, it is recommended to apply 15-60 t/ha of organic fertilizer.
Under the soybean made full mineral fertilizer N45-60P45-120K45-80, through which increases the yield by 0.4-0.5 t/ha. More effective combined organic (20-25 t/ha) and mineral fertilizers.
Phosphorus-potassium fertilizers and manure are applied under autumn tillage, nitrogen fertilizers – in spring under cultivation. It is possible to divide phosphorus-potassium fertilizers in two parts: half for autumn tillage, the remaining part – in spring for cultivation, in rows and top dressing.
There is a high efficiency of local application of fertilizers. Complicated fertilizers are applied during sowing in the rate of 40-50 kg per hectare or as an additional fertilizer in the phase of budding.
Acidic soils are limed, which has a favorable effect on the activity of nodule bacteria.
Soybean is responsive to molybdenum and boron fertilizers, which have a positive effect on nitrogen fixation. Molybdenum fertilizers treat seeds at a rate of 40-50 grams of ammonium molybdate per hectare sowing rate.
Bacterial fertilizers such as nitragin and rhizotorfin show high efficiency.
Tillage
The main tillage of soybean in the Far East begins in late July-August. It consists of plowing to a depth of 19-22 cm with plows with skimmers and harrows. With shallow topsoil, plowing is carried out to its full depth with soil deepeners. Preliminary discing is carried out only if the fields are clogged with perennial weeds. Clay soils are discing.
On the levelled early ploughed soil creates conditions for the germination of perennial weeds, which are destroyed by fallow cultivators with combined working tools for cutting and combing out the weeds. The units are completed in a row and consist of three cultivators КПГ-4 or КПС-4. The fields clean of perennial weeds are cultivated by disc harrows.
In the European part of Russia after cereal predecessors spend 2-3 discing, followed by plowing to a depth of 22-25 cm (30 cm). With strong clogging of fields by root weeds do layer-by-layer tillage.
Snow retention methods are provided in winter.
In spring, the arable field is harrowed. Before sowing, a total cultivation by cultivators with two rows of tines for cutting weeds and two – for combing. At the same time the field is harrowed. Clean fields from perennial weeds are discing on the day of sowing instead of cultivation. Soils strongly compacted during autumn-winter period after harrowing are deeply loosened by non-moldboard implements with simultaneous harrowing. Then, depending on weather conditions, 1-2 cultivations are made.
An important technique in all regions of soybean cultivation is to level the surface of the fields after plowing. At autumn leveling, in spring it is limited to harrowing and pre-sowing cultivation. At spring leveling it is carried out before pre-sowing cultivation with harrowing.
If after pre-cultivation the soil is heavily loosened and becomes dry, it is rolled with ring rollers.
Sowing
Seed preparation
Calibrated and dressed seeds of approved varieties are used for sowing.
On the day of sowing, seeds are treated with bacterial fertilizers, such as nitragyne or soybean rhizotorfin (nodule bacteria of other legumes do not form nodules on soybean roots), and microfertilizers.
To combat major diseases of soybeans it is carried out seed dressing chemicals 30-40 days before sowing, so that the drug did not have a negative effect on the bacterial fertilizers, treatment of which is made on the day of sowing. Rhizobium japonicum is specific for soybeans.
Sowing dates
Sowing begins when the soil at a depth of 10 cm warms 10-12 °C. Or at the depth of seed embedding – 10-14 °C.
Very early sowing leads to the fact that the seeds get into the cold, sprouts get sparse. Late sowing causes the soil to dry out.
Sowing methods
Sowing method is single row wide-row. The width between the rows is 45 cm, under irrigation, as well as in arid conditions of the European part of Russia and without the use of herbicides – 60-70 cm. Two- and three-line methods are also used in the Far East.
Indeterminant varieties are used as a vegetable crop and grown with a small distance between rows, usually 5-15 cm in a row and 50-60 cm between rows. Seeds are sown to a depth of 2 to 4 cm.
Seeding units include three SZSSh-3.6 seeders on a rigid hitch, equipped with trace indicators.
Seeding rates
Seeding rate of soybean 500-750 thousand/ha of germinated seeds or 40-80 kg/ha.
Optimal density of the plants is determined by the length of the growing season. For late- and mid-season varieties it is 300-400 thousand, medium-early – 500-600 thousand, early-ripening – 700-800 thousand pieces/ha.
Depending on the weight of the seeds sowing rate varies from 40-60 to 120-140 kg/ha.
Sowing depth
The depth of soybean seeds sowing in conditions of sufficient moisture is 4-5 cm, and 6-8 cm if the top layer dries out and on light soils.
Crop care
After sowing, the dry soil is rolled with ring or ring-spiked rollers.
The care of soybean crops includes harrowing and inter-row cultivation. Without the use of herbicides, as a rule, one pre-emergent harrowing with light harrows and one or two post-emergent cultivations with medium tooth harrows are performed. The first post-emergent harrowing is done in the phase of the formation of the first triple leaf. Harrowing increases the yield by 0.2-0.3 t/ha.
Cultivators КРН-4,2 with weeding harrows КРН-38 perform inter-row cultivation to the closing of the rows. Depending on the weed infestation of crops, the number of inter-row treatments is 1-3.
Main diseases of soybean: fusariosis, verticillosis, ash root rot, sclerotinia, alternariosis. The main methods of control are crop rotation and chemical means.
The main pests of soybeans are: mite, moth, soybean leaf beetle, meadow moth.
Irrigation
Cultivation of soybean under irrigation, especially in the arid steppe zone of the European part of the country, allows to increase the yield in 1,5-2,0 times.
The optimum water regime is as follows: soil moisture at a depth of 50-70 cm should be at least 70% of the lowest moisture capacity at the beginning of vegetation, at the phase of flowering and inflation of seeds – at least 80%.
The number of watering per growing season is 3-5 times. The irrigation norm is from 300-400 to 500-600 m3/ha. The main method of irrigation is sprinkling.
Harvesting
Harvesting of soybean begins when the stems and beans turn brown (for most varieties) and when the leaves turn yellow and fall off.
Due to the fact that mature beans do not crack (except in dry conditions), soybeans can be harvested in either a single- or a two-phase operation. During dry and warm weather, direct harvesters are used. But more often the low-cut biphase method is used.
Soybean are harvested with low-cut harvesters with re-equipped reapers on which the front ring tier and the base plate are rearranged to ensure a 4-5 cm cut of the plants. Also on the reaper the stabilizing mechanism is installed, the rotational speed of threshing drum is reduced to 400-450 per minute (500-600), the optimal clearance of threshing and separating devices of the combine is regulated.
Post-harvest handling of seeds performed in-line grain cleaning lines, including machines ОВП-20А and СМ-4 with pneumatic separators СП-0,5 and a slow-speed scraper burrows to separate damaged, immature, chopped and sick seed and reduce crushing during cleaning. Grain is dried by active ventilating or in dryers to a humidity not exceeding 10-12%.
Seeds are stored at a moisture content not exceeding 14%.
When growing soybeans as a vegetable crop, the pods are harvested when they have reached their full size, but before maturity, and when the seeds are soft enough.
Varieties
Depending on the length of the growing season, soybean varieties are divided into:
- ultra-ripe – less than 80 days;
- very early-ripening – 81-90 days;
- early-ripening – 91-110 days;
- medium-ripening – 111-120 days;
- medium-ripening – 120-130 days;
- medium-late – 131-150 days;
- late-ripening – 151-160 days;
- very late-ripening – 161-170 days;
- exceptionally late-ripening – more than 170 days.
Medium-ripening and early-ripening varieties are the most common in Russia. Ultra-early-ripening varieties are promising in the northern regions of soybean cultivation.
Some varieties have a specific vegetable purpose for which the seeds are used directly, and for others, sprouts obtained from the germinated seed are of significant use. Seeds of some varieties are used specifically for oil production.
VNIIS 1. This variety was bred by the All-Russian Research Institute of Soybean. It is an early maturing variety with high yields. Resistant to lodging and cracking of the beans. Plant height varies from 60 to 90 cm, the height of the attachment of the lower beans – 12-15 cm. Weight 1000 seeds from 156 to 164 g, the content of protein – 37-43%, oil – 21%. Yields are 2.4 t/ha. Released in the Amur region, Khabarovsk and Primorsky krais.
Amber. This variety was developed by the All-Russian Research Institute of Soybean. It is highly adaptable to local growing conditions; it does not lodge or crack when ripening. Resistant to diseases and pests. Medium early, plant height 80 cm, the attachment of the lower beans – 15 cm. Weight of 1,000 seeds from 160 to 190 g, the content of protein – 39%, oil – 20%. Yields more than 2.0 t / ha. Zoned in the Far East.
Change. Quality bred by the All-Russian Institute of Soybean Science. It is an early maturing, highly plastic. The plant height is 60-65 cm, the attachment of the lower beans – 10-18 cm. Seeds are rounded, yellow, weight of 1000 seeds 126-176 g, protein content – 39-42%, oil – 18-21%. Resistant to lodging and cracking beans. Yields are 2.8 t/ha. Released in the Amur region.
VNIIMK 9186. This variety was developed by the All-Union Institute of Oil Crops. It is a middle-ripening variety with a high yield. The plant height is 70-90 cm, the attachment of the lower beans – 10-15 cm from the soil surface, weight of 1000 seeds 110-160 g, protein content – 38-43%, oil – 17-21%. Maximum yield under irrigation is 4.2 t/ha. Zoned in the Krasnodar Territory and Rostov Region.
Kirovogradskaya 4. Variety bred Kirovograd regional agricultural testing station. Medium maturing, productive. The height of plants under irrigation 110-120 cm, the attachment of the lower beans – 15 cm from the soil surface, weight of 1000 seeds 170 g, protein content – 37-43%, oil – 17-19%. Average lodging resistance. Yield under irrigation is more than 3.0 t/ha. It is cultivated in Saratov and Astrakhan regions and Kirovograd region of Ukraine.
The varieties Belosnezhka, Komsomolka, Aurora, Volna, Beltskaya 25 and others are distributed in the European part of the country.
Sources
V.V. Kolomeychenko. Horticulture/Textbook. – Moscow: Agrobiznesentr, 2007. – 600 с. ISBN 978-5-902792-11-6.
Horticulture/P.P. Vavilov, V.V. Gritsenko. Vavilov. ed. by P.P. Vavilov, V.S. Kuznetsov et al. – M.: Agropromizdat, 1986. – 512 p.: ill. – (Textbook and Tutorials for Higher Education Institutions).
Fundamentals of agricultural production technology. Farming and plant growing. Ed. by V.S. Niklyaev. – Moscow: “Bylina”. 2000. – 555 с.
World vegetables : principles, production, and nutritive values / Vincent E. Rubatzky and Mas Yamaguchi. — 2nd ed. 1996.