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Soybean Cultivation

The soybean (U.S.) or soya bean (UK) (Glycine max) is a species of legume native to East Asia. It is an annual plant that may vary in growth, habit, and height. It may grow prostrate, not growing higher than 20 cm (7.8 inches), or even up to 2 meters (6.5 feet) in height. The pods, stems, and leaves are covered with fine brown or gray pubescence. The leaves are trifoliolate, having 3 leaflets per leaf, and the leaflets are 6–15 cm (2–6 inches) long and 2–7 cm (1–3 inches) broad. The leaves fall before the seeds are mature. The small, inconspicuous, self-fertile flowers are borne in the axil of the leaf and are white, pink or purple. The fruit is a hairy pod that grows in clusters of 3–5, with each pod 3–8 cm (1–3 inches) long and usually containing 2–4 (rarely more) seeds 5–11 mm in diameter.

Like some other crops of long domestication, the relationship of the modern soybean to wild-growing species can no longer be traced with any degree of certainty. It is a cultural variety (a cultigen) with a very large number of cultivars. However, it is known that the progenitor of the modern soybean was a vine-like plant that grew prone on the ground.

Soybean
Scientific classification
Kingdom: Plantae Phylum: Magnoliophyta Class: Magnoliopsida Order: Fabales Family: Fabaceae Subfamily: Faboideae Genus: Glycine Species: G. max
Binomial name
Glycine L. max (L.) Merr.

The genus Glycine Willd. is divided into two subgenera(species), Glycine and Soja. The subgenus Soja(Moench) includes the cultivated Soybean, G. max(L.)Merrill, and the wild soybean, G. soja Sieb.& Zucc. Both species are annual. The soybean grows only under cultivation while G. soja grows wild in China, Japan, Korea, Taiwan and Russia. Glycine soja is the wild ancestor of the soybean: the wild progenitor. At present, the subgenus Glycine consists of at least 16 wild perennial species: for example, Glycine canescens, and G. tomentella Hayata found in Australia and Papua New Guinea [1]

Beans are classed as pulses whereas soybeans are classed as oilseeds. It is a versatile bean, having a diverse range of uses.

The English word soy is derived from the Japanese pronunciation of shōyu), the Japanese word for soy sauce; soya comes from the Dutch adaptation of the same word,  in traditional Chinese) is itself a word of Chinese origin.[2][3]

 

Varieties of soybeans are used for many purposes. Soybeans are an important global crop, providing oil and protein. The bulk of the crop is solvent-extracted for vegetable oil and then defatted soy meal is used for animal feed. A small proportion of the crop is consumed directly by humans. Soybean products appear in a large variety of processed foods.
 

Soybeans were a crucial crop in eastern Asia long before written records, and they remain a major crop in China, Japan, and Korea . Prior to fermented products such as soy sauce, tempeh, natto, and miso, soy was considered sacred for its use in crop rotation as a method of fixing nitrogen. The plants would be plowed under to clear the field for food crops. Soy was first introduced to Europe in the early 1700s and the United States in 1765, where it was first grown for hay. Benjamin Franklin wrote a letter in 1770 mentioning sending soybeans home from England. Soybeans did not become an important crop outside of Asia until about 1910. In America, soy was considered an industrial product only and not utilized as a food prior to the 1920s. Soy was introduced in Africa from China in the late 19th Century and is now widespread across the continent.

Cultivation is successful in climates with hot summers, with optimum growing conditions in mean temperatures of 20 °C to 30 °C (68°F to 86°F); temperatures of below 20 °C and over 40 °C (68 °F, 104 °F) retard growth significantly.  They can grow in a wide range of soils, with optimum growth in moist alluvial soils with a good organic content. Soybeans, like most legumes, perform nitrogen fixation by establishing a symbiotic relationship with the bacterium Bradyrhizobium japonicum (syn. Rhizobium japonicum; Jordan 1982).  However, for best results an inoculum of the correct strain of bacteria should be mixed with the soybean (or any legume) seed before planting. Modern crop cultivars generally reach a height of around 1 m (3 ft), and take 80–120 days from sowing to harvesting.

Soyabean output 2005 shown as a percentage of the top producer, USA 83,368,000 tons.

Soybeans are native to east Asia, but 45 percent of the world's soybean area, and 55 percent of production, is in the United States. The U.S. produced 75 million metric tons of soybeans in 2000, of which more than one-third was exported. Other leading producers are Brazil, Australia, Argentina, China, and India.

Environmental groups, such as Greenpeace and the WWF, have reported that both soybean cultivation and the probability of increased soybean cultivation in Brazil, has destroyed huge areas of Amazon rainforest and is encouraging further deforestation. American soil scientist Dr. Andrew McClung, who first showed that the infertile Cerrado region of Brazil could grow soybeans, was awarded the 2006 World Food Prize on October 19, 2006.[5]

The first research on soybeans in the United States was conducted by George Washington Carver at Tuskegee, Alabama, but he decided it was too exotic a crop for the poor black farmers of the South so he turned his attention to peanuts.

Production History

According to the ancient Chinese, in 2853 BC the legendary Emperor Shennong of China named five sacred plants – soybeans, rice, wheat, barley, and millet.[6] The origins of the soybean plant are obscure, but many botanists believe it to have derived from glycine ussuriensis, a legume native to central China.[7] The soybean has been used in China for 5,000 years as a food and a component of medicines. Cultivation of the soybean, long confined chiefly to China, gradually spread to other countries.[8]

According to other sources, the earliest preserved soybeans were unearthed from archaeological sites in Korea[9][10]. AMS radiocarbon dating on soybean recovered through flotation during excavations at the Early Mumun Period Okbang site in Korea indicates that soybean was cultivated as a food crop in ca. 1000–900 BC. [11]. The best current evidence on the Japanese Archipelago suggests that soybean cultivation occurred in the early Yayoi period.

From about the first century AD to the Age of Discovery (15-16th century), soybeans were introduced into several countries such as Japan, Indonesia, the Philippines, Vietnam, Thailand, Malaysia, Burma, Nepal and India. The spread of the soybean was due to the establishment of sea and land trade routes. The earliest Japanese textual reference to the soybean is in the classic Kojiki (Records of Ancient Matters) which was completed in 712 AD.

During World War II, soybeans became important in both North America and Europe chiefly as substitutes for other protein foods and as a source of edible oil. In the United States they are now a leading crop, and Brazil, Argentina, and Paraguay also are significant soybean-exporting nations.

Many people have claimed that soybeans in Asia, prior to modern times, were only used after a fermentation process. However, this appears to be incorrect: Terms similar to "soy milk" have been in use since 82 AD [2], and there is evidence of tofu consumption that dates to 220.[3]

The genus name Glycine was originally introduced by Linnaeus(1737) in his first edition of Genera Plantarum. The word glycine is derived from the Greek-glykys(sweet)- and very likely refers to the sweetness of the pear-shaped (apios in Greek) edible tubers produced by the native North American twining or climbing herbaceous legume, Glycine apios, now known as Apios americana . Some alternative names are: ground nut, American potato bean, wild bean, Indian potato, ground bean, hopniss, and sea vines. The seeds are also edible. It saved the Massachusetts Bay Pilgrims from starvation.[12] The cultivated soybean first appeared in the Species Plantarum, Linnaeus, under the name Phaseolus max L. The combination, Glycine max(L.) Merr., as proposed by Merrill in 1917, has become the valid name for this useful plant.

Genetic modification

Soybeans are one of the "biotech food" crops that have been genetically modified, and GM soybeans are being used in an increasing number of products. In 1995 Monsanto introduced Roundup Ready (RR) soybeans that have had a copy of a gene from the bacterium, Agrobacterium sp. strain CP4, inserted into its genome by means of a gene gun, that allows the transgenic plant to survive being sprayed by this non-selective herbicide, Roundup. Glyphosate, the active ingredient in Roundup, kills conventional soybeans. The bacterial gene is EPSP (5-enolpyruvyl shikimic acid-3-phosphate) synthase. Soybeans also have a version of this gene, but the soybean version is sensitive to glyphosate, while the CP4 version is not.[13]

RR soybeans allow a farmer to spray widely the herbicide Roundup and so to reduce tillage or even to sow the seed directly into an unplowed field, known as no-till farming or conservation tillage. No-till agriculture has many advantages, greatly reducing soil erosion and creating better wildlife habitat;[14] it also saves fossil fuels and sequesters CO2, a greenhouse effect gas.[15] It should be noted that RR soybeans simplify the process, but are not a requirement for no-till agriculture. Roundup may be sprayed on the field (and weeds) before the non-RR soybeans have emerged from the soil.

In 1997, about 8% of all soybeans cultivated for the commercial market in the United States were genetically modified. In 2006, the figure was 89%. As with other "Roundup Ready" crops, concern is expressed over damage to biodiversity.[16] However, the RR gene has been bred into so many different soybean cultivars that the genetic modification itself has not resulted in any decline of genetic diversity, as demonstrated by a study on genetic diversity[17]

The ubiquitous use of such types of GM soybeans in the Americas has caused problems with exports to some regions. GM crops require extensive certification before they can be legally imported into the European Union, where there is extensive supplier and consumer reluctance to use GM products for consumer or animal use. Difficulties with coexistence and subsequent traces of cross-contamination of non-GM stocks have caused shipments to be rejected and have put a premium on non-GM soy.[18]

Soybean Diseases

from http://www.btny.purdue.edu/Extension/Pathology/CropDiseases/Soybean/Soybean.html

Department of Botany and Plant Pathology
Purdue University
West Lafayette, IN 47907

SOYBEAN Disease Name: Bacterial Blight Pathogen: Bacterium. Pseudomonas syringae pv. glycinea Symptoms: Initial symptoms are small angular watersoaked spots on leaves. Lesion centers dry out and turn brown to black with watersoaked margins and yellow halos. Lesions may coalesce resulting in large blighted areas. Affected tissue often drops out, giving a tattered appearance to the leaves. Rarely a serious disease in Indiana soybeans. Conditions: Cool, rainy weather. Outbreaks often follow thunderstorms. Inoculum Survival: Seed, infected crop residue. Inoculum Dispersal: Airborne bacteria from rainsplash, mechanical (cultivators). Management: Resistant cultivars, plant pathogen-free seed, crop rotation, avoid cultivation when foliage is wet.

SOYBEAN Disease Name: Brown Spot Pathogen: Fungus. Septoria glycines Symptoms: Irregular light-brown lesions, ranging in size from small specks to a few mm in diameter. Lesions eventually darken to brownish black. Lesions are primarily found on leaves, but can also occur on stems, petioles and pods. Early season infection is restricted to unifoliate and first trifoliate leaves. Conditions: Extended warm, wet weather. Inoculum Survival: Seed, infected crop residue. Inoculum Dispersal: Airborne spores. Management: Plant pathogen-free seed, crop rotation, foliar fungicide at R-3 stage, plow under crop residue.

SOYBEAN Disease Name: Pod and Stem Blight Pathogen: Fungi. Diaporthe phaseolorum var. sojae and Phomopsis longicola Symptoms: No definite leaf or stem lesions are produced under field conditions. Fungal spore-bearing structures (pycnidia) appear as black specks in linear rows on dead stems and poorly-developed pods. Pod blight phase results in poor quality seeds and seed decay. Seedling blight may occur from seed infections. Conditions: Warm wet weather at R7 to R8 stages favors seed infection and decay. Inoculum Survival: Seed, infected crop residue. Inoculum Dispersal: Airborne spores. Management: Crop rotation, seed-applied fungicides for seedling blight. Foliar fungicide at R6 stage in seed production fields if risk of seed infection is high. Timely harvest.

SOYBEAN Disease Name: Downy Mildew Pathogen: Fungus. Peronospora manshurica Symptoms: Pale green to yellow spots on upper leaf surface. Lesions turn grayish brown to dark brown with a yellow or light green margin. Tufts of gray fungal growth may be visible on lower leaf surface during moist weather. Severely affected leaves turn brown and drop. Whitish fungal growth may be present on interior of pods and seed coats. Systemically infected seedlings from infected seeds are stunted with mottled foliage. A common disease, but rarely causes significant yield loss. Conditions: High humidity and cool temperatures favor disease. Inoculum Survival: Seed, infected crop residue. Inoculum Dispersal: Airborne spores. Management: Crop rotation, plow under crop residue, resistant cultivars, fungicide seed treatment.

SOYBEAN Disease Name: Phytophthora Rot Pathogen: Fungus. Phytophthora sojae Symptoms: Seed rot and pre-emergence damping-off. Root and stem rot of older seedlings. In more mature plants chlorosis and wilting of leaves, with a dark brown discoloration on lower stem progressing upward from the soil line. Root rot of older plants may also occur. Affected plants are clustered in field. Conditions: Heavy soils and soil saturation for more than 24 hours promote disease. Disease is more severe with reduced-till. Highest risk with no-till. Inoculum Survival: Soil, infected crop residue. Inoculum Dispersal: Soilborne spores. Management: Resistant cultivars, fungicide (metalaxyl) seed treatment or metalaxyl in seed furrow, improve soil drainage.

SOYBEAN Disease Name: Rhizoctonia stem rot Pathogen: Fungus. Rhizoctonia solani Symptoms: Pre-emergence or post-emergence damping off of seedlings. Brown or reddish brown lesions on larger seedlings and young plant stems at the soil line and on the taproot. Infected stems may break in the lesioned area. Conditions: Stress conditions- soil compaction, planting too deep, chemical damage. Warm and dry soil prior to planting followed by wet conditions after planting favors disease. Inoculum Survival: Soil, infected crop residue. Inoculum Dispersal: Soilborne hyphal fragments and survival structures. Management: Systemic fungicide seed treatments. Promote good soil conditions that favor rapid seedling development. Avoid herbicide or other chemical damage. Avoid planting too deeply and compacting soil.

SOYBEAN Disease Name: Sclerotinia Stem Rot Pathogen: Fungus. Sclerotinia sclerotiorum Symptoms: Wilting and death. Dead leaves remain attached to stems. Tan to white lesions at nodes can girdle stems. Cottony fungal growth may be present on diseased plant parts. Large black structures (sclerotia) form in pith and on infected stems. Conditions: Cool, wet weather favors disease. Inoculum Survival: Sclerotia in soil, infected crop residue, seed. Sclerotia may survive for up to 7 years. Inoculum Dispersal: Airborne spores from structures on sclerotia. Management: Deep plow to bury sclerotia, then work soil shallow for 5 + years to keep sclerotia below soil surface. No-till a nonhost crop (corn, sorghum, small grains) for 2 years. Avoid close spacing and tall, bushy cultivars in fields with disease history. Avoid excessive irrigation before flowering. Cultivars with cv. Williams in parentage may be more susceptible.

SOYBEAN Disease Name: Brown Stem Rot Pathogen: Fungus. Phialophora gregata Symptoms: Symptoms are usually not evident until late in the growing season. Leaves may suddenly discolor, with brown tissue between veins and green tissue along veins. Leaves remain attached. Browning of pith inside stem of infected plants. Conditions: Disease progresses more quickly in older than younger plants, regardless of temperature. Inoculum Survival: Soil, infected crop residue. Can survive 3-5 years. Inoculum Dispersal: Soilborne hyphal fragments and spores. Management: Resistant cultivars. Avoid susceptible cultivars for 3 years.

SOYBEAN Disease Name: Sudden Death Syndrome Pathogen: Fungus. Fusarium solani race A Symptoms: Yellow interveinal blotches, which become necrotic leaving green tissue along the leaf veins. Leaf blades drop, leaving petioles attached to the stem. Foliar symptoms similar to brown stem rot. Light brown or gray discoloration occurs in internal taproot tissue, while pith remains white. Conditions: Often occurs with soybean cyst nematode, but SCN not necessary for disease to occur. Cool wet soils in early spring favor infection. Inoculum Survival: Soil, infected crop residue. Inoculum Dispersal: Soilborne spores and hyphal fragments. Management: Crop rotation. Plant as late as possible in the spring, and use cultivars from more than one maturity group. Manage SCN. Timely harvest.

SOYBEAN Disease Name: Charcoal Root Rot Pathogen: Fungus. Macrophomina phaseolina Symptoms: Loss of vigor in mature plants. Leaves turn yellow and wilt but remain attached. Light gray or silver discoloration in taproot and lower stem after flowering. Small black fungal structures (microsclerotia) present in taproot and stem tissues. Conditions: High soil temperatures, dry weather. Plants that are under stress from adverse environmental or cultural conditions are more susceptible. Inoculum Survival: Microsclerotia in soil or infected crop residue. Inoculum Dispersal: Soilborne microsclerotia. Management: Crop rotation, adequate fertilization, irrigate to keep soil moisture high, seeding density and planting date to encourage early canopy closure.

SOYBEAN Disease Name: Soybean Cyst Nematode Pathogen: Nematode. Heterodera glycines Symptoms: Slight to severe stunting with slight to severe chlorosis. Gradual yield decline over several years. Decreased nodulation, and canopy slow to close. Symptoms are similar to nitrogen and/or potassium deficiency. Some root decay. Cysts on roots first appear as white, lemon-shaped females on root surface. Cysts turn dark brown with age. Conditions: Symptoms are more pronounced under dry soil or other stress conditions. Can occur in any soil type, but often more apparent in light or sandy soils. Inoculum Survival: Cysts in soil. Inoculum Dispersal: Soilborne cysts and juvenile nematodes. Management: Crop rotation for 2 or more years between susceptible crops, good weed control, resistant cultivars. Avoid moving infested soil with equipment or seed.

SOYBEAN Disease Name: Bud Blight Pathogen: Virus. Tobacco Ringspot Virus Symptoms: Stunting occurs when young plants are infected. Minor disease in most fields in most years. Stem terminal will curve, forming a crook. Lateral buds become brown and drop off. Brown discoloration of stems, beginning at nodes. Leaves are dwarfed and curl upward. Pods often abort, or are underdeveloped. Infected plants remain green longer that healthy plants (delayed maturity). Symptoms often develop first on plants near the edges of a field. Conditions: Warm, dry conditions that favor vector development. Inoculum Survival: Seed, possibly weed hosts. Inoculum Dispersal: Vector. Thrips, dagger nematodes. Management: Virus-free soybean seed.

SOYBEAN Disease Name: Soybean Mosaic Pathogen: Virus. Soybean Mosaic Virus Symptoms: Stunting, mottling and curling of leaves. Leaves may be puckered and misshapen, resembling 2,4-D injury. Diseased pods may be stunted and curved. Seeds from diseased pods may be discolored (hilum bleeding). A common disease, but rarely causes significant yield losses. Conditions: Cool, dry conditions which favor vector. Inoculum Survival: Seed. No overwintering hosts in northern US. Inoculum Dispersal: Vector. Aphids. Management: Resistant cultivars, virus-free soybean seed, remove symptomatic plants from seed production fields.

References

1.  http://www.nsrl.uiuc.edu/news/nsrl_pubs/sbr1995/ArticleID.pdf
2.  soy, n.¹ The Oxford English Dictionary: Second Edition. 1989. Accessed December 14, 2007.
3.  soya, n. The Oxford English Dictionary: Second Edition. 1989. Accessed December 14, 2007.
4.  Blackman, SA; Obendorf RL, Leopold AC (Sept 1992). "Maturation Proteins and Sugars in Desiccation Tolerance of Developing Soybean Seeds" (1.2M PDF, or scanned pages). Plant Physiol. 100 (1): 225–30. Full text at PMC: 1075542. Retrieved on 2006-10-21.
5.  Lang, Susan. "Cornell alumnus Andrew Colin McClung reaps 2006 World Food Prize", Cornell University, 2006-06-21. Retrieved on 2006-10-21.
6.  History of Soybeans. Soya - Information about Soy and Soya Products. Accessed January 15, 2008
7.  Soybean. Encyclopædia Britannica Online. Accessed January 15, 2008
8.  Soybean. Columbia Encyclopedia, Sixth Edition. 2001-07. Accessed January 15, 2008
9.  Crawford, Gary W. 2006. East Asian Plant Domestication. In Archaeology of East Asia, edited by Miriam Stark. Blackwell, Oxford, pp. 81.
10.  Crawford and Lee 2003
11.  Crawford and Lee 2003:90
12.  http://www.bio.umass.edu/biology/conn.river/groundnt.html
13.  Padgette SR, Kolacz KH, Delannay X, Re DB, LaVallee BJ, Tinius CN, Rhodes WK, Otero YI, Barry GF, Eichholz DA, Peschke VM, Nida DL, Taylor NB, Kishore GM (1995) Development, identification, and characterization of a glyphosate-tolerant soybean line. Crop Sci 35:1451-1461
14.  Conservation Technology Information Center, http://www.conservationinformation.org/
15.  Brookes G and Barfoot P (2005) GM crops: The global economic and environmental impact—the first nine years 1996–2004. AgBioForum 8:187-195
16.  Liu, KeShun (1997-05-01). Soybeans : Chemistry, Technology, and Utilization (Hardcover), Springer, 532. ISBN 0-8342-1299-4.
17.  Sneller CH (2003) Impact of transgenic genotypes and subdivision on diversity within elite North American soybean germplasm. Crop Sci 43:409-414.
18.  EU caught in quandary over GMO animal feed imports The Guardian, 7 December 2007

19.  United States Department of Agriculture, Agricultural Statistics 2004. Table 3-51.

United Soybean Board

Soyinfo Center - SoyaScan database and books

Guardian - There's no risk to humans from soya

International Institute of Tropical Agriculture

American Soybean Association

Cornell University Food and Brand Lab

Purdue University Department of Botany

Sourced from wikipedia.org