Agriculture and Environment: Commodities

Overview: Soybeans (Glycine max)

Soybeans were first cultivated in China perhaps as many as 6,000 years ago, making soybeans one of the first domesticated food crops

During the Zhou Dynasty (eleventh century to 256 B.C.) and the Qin Dynasty (221 to 206 B.C.) soybeans became one of the main food crops in the Yellow River Valley. By the Ming Dynasty (1368 to 1644 A.D.), soybeans were grown throughout the country.

King of beans
The soybean is the "king of beans." Dry, it contains 38% protein - twice as much as pork, 3 times more than egg, and 12 times more than milk. Furthermore, the protein in soybean has a more complete range of essential amino acids than most other foods.

In addition, the dry seed contains 18.4% unsaturated fat. Many soybeans products (e.g., miso, soy sauce, tempeh, and bean curd) originated in China. For example, bean curd (tofu) was invented in the Han Dynasty (206 B.C. to 220 A.D.). The technology then spread to Japan around the year 700 A.D. (Tengans and Nilsson 2002).

Chinese Origins
Soybeans, along with silk, tea, and porcelain, were one of the earliest exports from China. China displayed soybeans at the Vienna Fair in 1873, and the product then became better known to the outside world. At the beginning of the twentieth century, China began to export soybeans. Production in China reached 11.3 million metric tons in 1936 and accounted for 80-90% of the world market (Tengnas and Nilsson 2002).

The many uses of soybeans
Initially, soybeans were used primarily, for human consumption and still are in parts of Asia. In the United States, though, soybeans have not been grown for direct human consumption until recently. Rather, they are grown primarily to provide cheap edible oil and high-protein animal feed.

Soybean meal was first a by-product from the crushing of soybeans for oil. Soybean oil is now the most consumed oil in the world. Soybean meal was developed as a substitute for fish meal that left no fishy taste. Confined poultry and pork operations developed as a result of the availability of a relatively cheap, nutritious feed source for animals.

The spread of soybean cultivation
After World War II soybean production was introduced in many parts of the United States. By the 1960s the cultivation of soybeans had expanded rapidly, displacing many other crops and becoming the main rotational crop in association with corn. Soybean production was encouraged by agricultural extension agents because the crop is a legume and fixes nitrogen in the soil for uptake by subsequent crops of corn.

Monocrop soybean production systems
Through the development of different seed varieties, improved nutrient input packages, and mechanised planting and cultivation, a monocrop soybean production system was developed in the United States. This monocrop technology has been adapted to local conditions and spread throughout the United States and the world, including some of the world's most biodiverse ecoregions.

Rapid expansion into natural habitats
Of particular concern from an environmental point of view is the rapid expansion of soybean cultivation into the natural habitat of the Brazilian cerrado (a relatively flat, mixed woodland and savanna area of central Brazil). Soybean production has spread even more rapidly throughout Brazil than it did in the United States.