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Soybeans

Soybeans are an oil-bearing and leguminous agricultural crop.

Economic importance

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, soybeans 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.

Unripe soybean seeds are used to make preserves and sauces.

Previously, soybeans 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, soybeans are mainly grown for seed. Mixed crops of soybeans 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

Soybeans come from Southeast Asia. It was cultivated in China six thousand 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 obtaining vegetable protein and oil; the ways of eating it are diverse. More than 250 dishes are known.

In the late 8th century, soybeans were introduced to Europe.

China introduced soybeans into the Russian Far East.

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 U.S. planted an area of 27 million hectares and China planted 8 million hectares. Japan, Vietnam, Korea, Europe, North Africa, North and South America (Brazil) and Australia are also major producers of soybeans.

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 (Glicine hispida Maxim.) is an annual plant of the legume family (Fabaceae).

Its root system is taprooted, penetrating into the soil up to 1.5-2 m deep.

The stem is strong, erect, strongly branching, not lodging, forming a bush of 45 to 150 cm in height.

Leaves 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.

Beans have different shapes and colors, contain 1-5 seeds, usually do not crack.

Stems, leaves, and beans are covered with dense stiff whitish or red hairs.

Seeds are round, oval or oblong-flat, yellow, green, brown or black depending on the variety. Weight of 1000 seeds is 100-400 g.

Biological features

Temperature requirements

Soybeans 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.

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 different soils, except for the acidic, highly saline, waterlogged, heavy and very light ones. Loamy and sandy loamy chernozem soils are optimal.

Optimal soil acidity is 6.5-7. High yields are obtained only on organic-rich fertile soils with neutral reaction.

Vegetation

The growing season is 80 to 170 days.

Duration of flowering is 15 to 40 days depending on cultivar, with late cultivars up to 80 days.

Vegetation phases:

  • sprouts;
  • first true leaf;
  • branching;
  • flowering;
  • fruiting;
  • ripening.

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, soybeans 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, soybeans 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, soybeans 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 soybeans 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.

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

The method of sowing wide row by single-line method. The width between the rows is 45 cm under irrigation, and in arid conditions of the European part of Russia and without herbicides – 60-70 cm. Two- and three-line methods are also used in the Far East.

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 soybeans 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

Irrigation
Cultivation of soybeans 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 soybeans begins when the stems and beans turn brown (for most varieties) and when the leaves turn yellow and fall off.

Because mature beans do not crack, soybeans can be harvested in either a single- or two-phase operation. During dry and warm weather, direct harvesters are used. But more often the low-cut two-phase method is used.

Soybeans 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%.

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.