Plant 321

Glycine max (L.) Merr. (Fabaceae)

Soya bean

In 1765, Samuel Bowen brought soya beans from China to Georgia in Colonial America, establishing the bean as a viable agricultural cottage industry. In the early twentieth century, USA soya bean cultivation was identified as a cost-effective way to improve agricultural soils and provide industrial raw materials. Like many other legumes, soya beans have root nodules that convert nitrogen in the air into forms of nitrogen that can be taken up by plant roots and hence increase soil fertility. Moreover, American industrialists soon discovered soya beans contain edible oil that can be transformed in everything from food and soap to paint and plastics.

The recent attention paid to soya beans in western culture belies their ancient roots in eastern cultures. Soya beans, liquidized, powdered and turned into curd, have long been used as protein- and oil-rich human food. Domesticated soya beans were probably selected from wild soya beans (Glycine soja) in north-east China before the tenth century BCE. Over three millennia many cultivars have been selected to satisfy the multifarious uses to which soya beans are put in east and south east Asia.

Meeting global meat demands, means having cheap, protein-rich animal feed. Economic, modern industrial animal farming would be impossible without soya-based feeds. In 1970, global soya bean production was less than 50 million tonnes; the USA supplied more than 70% of this. Today, global production is over 250 million tonnes; the USA has about 30% of the market, the other top producers are Argentina and Brazil.

In the late 1990s, soya beans became a central part of the arguments about the commercial production of genetically-modified crops, and the public acceptance of food containing genetically-modified organisms. Then, about 8% of all soya beans cultivated in the USA were genetically modified; today, this figure is over 90%.

Soya beans require vast areas of flat, well-watered land in an equable climate. In North America, land demands were satisfied by converting prairies to soya production. During the 1970s, attention turned to the vast, species-rich savanna in central Brazil and Bolivia, the cerrado. In the 1950s it had been discovered that the region's acidic, aluminium-rich, nutrient-poor soils could support crop production, such as soya, if they were improved by treatment with lime, gypsum and phosphate fertilizer. The cerrado has become a South American grain basket at Brazil's agricultural frontier. In a generation, the area of Brazil devoted to soya bean cultivation has tripled.

Further reading

Hymowitz, T. (1970) On the domestication of soybean. Economic Botany 24: 408-421.

Stark, M.T. (2005). Archaeology of Asia. New Jersey, Wiley-Blackwell.

WWF (2011) Soya and the cerrado: Brazil's forgotten jewel. WWF-UK Report, Cambridge.

Stephen Harris