Soybean

• 1. Introduction

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  The soybean, known to botanists as Glycine max, is a legume native to East Asia, and in June 1973 the United States briefly refused to sell it abroad. Traders had misread the soybean futures market, which wrongly signaled a major shortage. The Nixon administration answered with an export embargo. It lasted only a week. That was long enough for Japanese buyers to decide they could not rely on American supplies, and a rival soybean industry took shape in Brazil. Few crops can shift a global market in seven days. This documentary asks how a bean from East Asia became the most widely grown legume on Earth. It asks what people and animals do with it, and why the plant has crossed oceans and centuries to reach so many fields. And it asks what the planet pays for the bargain.

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• 2. Ancient Origins

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  Charred remains of wild soybean from Jiahu, a Neolithic site in Henan province in China, are the earliest documented trace of people using Glycine of any kind. The site was occupied between 9,000 and 7,800 years ago. Those beans were still wild. True domestication came later, most likely in the land between the Yellow River and the Huai River. Genomic data increasingly points to a single domestication event in north-central China, between 6,000 and 9,000 years ago. Some evidence hints at a messier story, with low-intensity cultivation in several parts of East Asia before the Chinese lineage won out. Scientists still debate where cultivation began.

  The wild ancestor, Glycine soja, grows naturally in China, Japan, Korea and Russia. After so many centuries of domestication, the tie between the modern bean and its wild relatives can no longer be traced with any certainty.

  Korea holds some of the oldest beans that look like modern ones. At the Okbang site, from the Early Mumun period, radiocarbon dating shows soybeans were grown as food around 1000-900 BC. The first unambiguously domesticated, cultigen-sized bean turned up at another Mumun-period site, Daundong. In Japan, Jōmon-period soybeans from 3000 BC are also much larger than wild ones. The earliest Japanese text to mention the plant is the Kojiki, or Records of Ancient Matters, completed in 712 CE.

  Myth gave the bean a place of honor. According to an ancient Chinese story, the legendary Emperor Shennong named five sacred plants in 2853 BC: soybeans, rice, wheat, barley and millet. Historically, soybeans were an important crop by the Zhou dynasty, around 1046-256 BC. Early Chinese records credit the Yangtze River delta and Southeast China as the source, yet no archaeology shows domestication in the south. Soy there seems to have been unknown before the Han dynasty. Long before anyone fermented it into sauces and pastes, people prized the plant for what it did in crop rotation, and they ate it plain, as bean curd, and as soy milk.

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• 3. On the Table

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  The English word soy comes from the Japanese soi, a Kagoshima dialect form of shōyu, which in turn comes from the Chinese jiangyou. That Chinese term simply means soy sauce. The bean, in other words, is named after its most famous product.

  Soy foods fall into two families. The unfermented family includes edamame and soy milk, and tofu and tofu skin are made from that milk. The fermented family includes soy sauce, fermented bean paste, nattō and tempeh. The earliest known written mention of tempeh appears in 1815 in a Javanese manuscript called the Serat Centhini, though the cake itself probably developed in Java around the 17th century.

  In Korea, soybean sprouts called kongnamul appear in many dishes, and the beans are the base of doenjang, cheonggukjang and ganjang. In northern Vietnam, soybean pastes such as tương Bần, tương Nam Đàn and tương Cự Đà garnish phở and gỏi cuốn. Japan gives us miso, nattō, kinako and edamame, which are immature beans boiled in the pod and served with salt. In China and Taiwan, soy milk called doujiang has been a breakfast staple for centuries, and cow's milk is the newer arrival.

  The bean itself is dense with nutrition. Dry soybeans are about 36% protein and 20% fat, and the protein is complete, which matters to vegetarians and vegans. Eaten raw, the beans are toxic to animals with a single stomach, because of trypsin inhibitors. Cooking, roasting or fermenting destroys them.

  The health questions are less settled than the nutrition. The United States Food and Drug Administration allows a claim that 25 grams of soy protein a day, within a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Evidence on cancer remains inconclusive, with a 2011 meta-analysis finding a lower breast cancer risk in Asian populations but not in Western ones. Soy is also on the European Union's list of 14 labelled allergens. One quiet difference may help explain the divide. Only 33% of Western Europeans carry gut microbes that turn the soy compound daidzein into equol, compared with 50-55% of Asians.

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• 4. Around the World

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  In 1603, Jesuit priests in Nagasaki published a Japanese-Portuguese dictionary titled Vocabvlario da Lingoa de Iapam. It defined about 20 words tied to soy foods, the first such definitions in any European language. By then, Portuguese, Spanish and Dutch traders were carrying soybeans and their products around Asia. By the 1600s the Dutch East India Company had also spread soy sauce from southern Japan across the Indian subcontinent.

  Java met the bean earlier. An old Javanese manuscript, the Serat Sri Tanjung, calls it kadêlê, and the manuscript dates to the 12th or 13th century. Traders from southern China probably brought it even sooner.

  Europe's first attempts came through botanical gardens. Turin's garden grew soybeans by 1760, and in France cultivation is recorded by 1779, perhaps as early as 1740. In Portugal the Botanical Gardens at Coimbra grew the plant in 1880. In France, a man named Li Yu-ying began working with the bean in 1910 and started a large tofu factory, which made the first commercial soy foods there.

  The most methodical champion was Professor Friedrich J. Haberlandt. At the Vienna World Exposition in 1873, he obtained seeds of 19 soybean varieties. He grew them in Vienna in 1875, and in early 1876 he sent samples to seven cooperators across central Europe. Their results were good or fairly good. Haberlandt published his findings in 1878 in a book called Die Sojabohne, which means The Soybean. In northern Europe, the lupin earned the nickname "soybean of the north".

  Elsewhere the dates arrive in a rush. Soybeans reached Africa through Egypt in 1857. The first reliable reference in Central America dates from Mexico in 1877. In South America, the soybean first arrived in Argentina in 1882.

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• 5. The Golden Bean

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  Samuel Bowen, a former East India Company sailor, brought soybeans from China to North America in 1765. He had visited China alongside James Flint, the first Englishman legally permitted by the Chinese authorities to learn Chinese. The first New World crop was grown on Skidaway Island, Georgia, by Henry Yonge, from seeds Bowen gave him. Bowen then grew soy near Savannah, possibly with money from Flint, and made soy sauce to sell to England. The same sauce carried soy to the Caribbean in 1767.

  For the next 155 years, American farmers grew the crop mainly as forage. Humans did not eat it in quantity until Lafayette Mendel and Thomas Burr Osborne showed that cooking, moisture or heat could raise the nutritional value of the seeds. William Joseph Morse is now considered the father of modern soybean agriculture in America. In 1910, he and Charles Piper began promoting what had been seen as an obscure Oriental peasant crop, renaming it the "golden bean".

  Henry Ford became an enthusiast. In 1931 he hired the chemists Robert Boyer and Frank Calvert to produce artificial silk. They spun soy protein into fibers and hardened them in a formaldehyde bath, creating a textile called Azlon. It never reached the commercial market. Ford did use soybean oil in automobile paint and as a fluid in shock absorbers. In 1936 his company worked out a method of rolling soybeans and fibers into a soup and pressing it into car parts, from distributor caps to dashboard knobs.

  Hard times also helped. During the Great Depression, drought-stricken Dust Bowl regions used soy to rebuild their soil, thanks to its nitrogen-fixing habit. World War II made the bean a stand-in for other protein foods and a source of edible oil.

  Still, before the 1970s the only regular eaters of soy foods in the United States were Asian-Americans and Seventh-Day Adventists. The movement toward wider eating began in small pockets of the counterculture, notably at a Tennessee commune called The Farm. A vegetarian revival then carried it further, helped by books such as The Book of Tofu. The scale of the change is startling. Soybeans were practically unseen in 1900, yet by 2000 they covered more than 70 million acres, second only to corn. In 2021, farmers planted 87,195,000 acres, with Illinois, Iowa and Minnesota leading.

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• 6. Seed and Soil

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  Under ideal conditions, a soybean seedling shows its first sign of life within 48 hours, when the radicle pushes out as the start of the root. The cotyledons, which work as both first leaves and food stores, then nourish the young plant for 7 to 10 days. After that, a new node forms about every four days, and roots can grow 2 cm per day before flowering. Mature plants reach 50-125 cm in height, with roots going down 75-150 cm.

  Day length decides when flowering starts, often once days shorten below 12.8 hours. The flowers are small, self-fertile and white, pink or purple. They need no pollinators, yet bees visit them for their sugary nectar. The fruit is a hairy pod, 3-8 cm long, grown in clusters of three to five. Each pod usually holds two to four seeds of 5-11 mm, in black, brown, yellow or green.

  The seed coat is a fortress. It is hard and water-resistant, and if it cracks, the seed will not germinate. At one end of the scar, called the hilum, sits the micropyle, a tiny opening that lets in water for sprouting. In the mid-1980s, A. Carl Leopold began studying how high-protein seeds such as soybeans survive drying and revive after taking in water. Working at the Boyce Thompson Institute for Plant Research at Cornell University, he found that soybeans and corn rely on a range of soluble carbohydrates to protect their cells. He won patents in the early 1990s for protecting membranes and proteins in the dry state.

  The plant also feeds itself. Bacteria called Bradyrhizobium japonicum live in nodules on the roots and capture nitrogen from the air. Nodulation begins by the time the third node appears and continues for about 8 weeks. That habit lets farmers cut nitrogen fertilizer for crops that follow soy in rotation. Modern cultivars stand about 1 m tall and take 80-120 days from sowing to harvest.

  The soil, however, is not always friendly. In the early 1950s, Andrew McClung showed that with soil amendments the Cerrado region of Brazil could grow soybeans. In 2006, the World Food Prize went to McClung and to Edson Lobato and Alysson Paolinelli of Brazil. They were honored for turning the biodiverse savannah of the Cerrado into highly productive cropland.

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• 7. Pests and Genes

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  Soybean cyst nematode is the worst soybean pest in the United States, and losses of 30% or 40% are common even when plants show no symptoms. Larger enemies exist too. Whitetail deer can cut yields by as much as 15% through feeding, trampling and bedding. A single den of groundhogs can eat a tenth to a quarter of an acre of soybeans. Smaller threats include the Japanese beetle, the corn earworm moth in Virginia, and Soybean dwarf virus, which aphids spread in Japan and the United States. The fungus Pythium spinosum attacks crops in Arkansas, Indiana and China.

  Breeders have answered the nematode with resistance, but the answer has a weak spot. Nearly all American cultivars with nematode resistance draw it from one breeding line, PI 88788. In 2012, only 18 of the 807 cultivars recommended by Iowa State University Extension had ancestry from anywhere else. By 2020, of 849 cultivars, 810 had some PI 88788 ancestry, 35 had Peking and just 2 had PI 89772. The nematode populations have responded, and many are now virulent on PI 88788.

  Genetic engineering offered another path. In 1995, the Monsanto company introduced soybeans tolerant to its glyphosate herbicides, using a swapped-in bacterial gene that glyphosate cannot block. Adoption was swift. About 8% of American commercial soybeans were genetically modified in 1997, and the figure reached 93% in 2010. Overseas, the European Union requires extensive certification before such crops can be imported. Traces of cross-contamination have caused shipments to be rejected and have put a premium on non-modified soy.

  The money did not flow evenly. A 2006 report from the United States Department of Agriculture put the overall benefit of genetically engineered soybeans in the country at $310 million. Seed companies took 40% of it, biotechnology firms 28% and farmers 20%. The patent on glyphosate-tolerant soybeans expired in 2014, so that split may shift.

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• 8. Feed and Forests

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  In 2020, the world grew more than 353 million tonnes of soybeans, and Brazil and the United States together supplied 66% of them. Brazil alone became the largest producer that year, with 131 million tons. Output has climbed everywhere since the 1960s, especially in South America after a cultivar suited to low latitudes appeared in the 1980s. China accounts for more than 60% of imports. Soy alone makes up four times as much legume production as all other legumes combined.

  Most of that harvest never becomes tofu. About 85% of the world's soybeans are crushed into meal and oil. Defatted meal holds roughly 50% protein, and 97% of it goes to feed livestock. In the European Union, soybean meal supplies around 60% of the protein given to livestock. In the United States, poultry is the biggest customer. Overall, around 80% of the global soybean crop feeds animals. The oil has its own markets. In 2022, China led soybean oil production with a 29% share, and the United States followed with 21%. In the United States, soybean oil supplies 80% of domestic biodiesel.

  The cost shows up in forests. An Amazon "Soy Moratorium" was meant to stop soy from driving clearing there, but indirect effects continue. Soy land often comes from pasture, which pushes into forest, or from areas the moratorium does not cover, such as the Cerrado. Roughly one-fifth of deforestation traces to expanding oilseeds, mainly soy and palm oil, while beef expansion accounts for 41%. The main driver is global demand for meat, which needs huge areas to grow feed.

  The people running these farms are often far away. In Brazil, managers frequently live remote from the sites they oversee and lean on zero tillage, heavy pesticide use and intense fertilization. In the early 2000s, American farm magazines promoted the Cerrado of Bahia as cheap land with ideal conditions, and a few dozen American farmers bought in. Some later planned to sell their now expensive Bahia holdings to buy cheaper land in the frontier regions of Piauí or Tocantins.

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