Groundnuts (Peanuts)

The groundnut is the largest nut crop in the world by a wide margin, and it is not a nut. World production runs about 57 million tonnes in shell a year. Set that against the tree nuts properly, on the same kernel basis and not shell against kernel, and the gap is still enormous: shelled at a typical 70 percent yield the groundnut crop is on the order of 40 million tonnes of kernels, against 6.0 million tonnes for the entire tree-nut complex of almonds, cashews, walnuts, pistachios, and hazelnuts put together (INC, 2024/25). The groundnut is therefore something like seven times all the world's tree nuts combined, and it gets a fraction of their attention. Botanically Arachis hypogaea is a legume, a member of the pea and bean family, and its defining trick is geocarpy: the flower is pollinated above ground, then the stalk behind it elongates into a "peg" that drives down into the soil, and the pod ripens underground in the dark. That is where the name comes from, and it is why groundnut is the more accurate word and peanut the more popular one. Like other legumes it fixes its own nitrogen, which is the second reason farmers grow it: it is a rotation crop that leaves the soil better than it found it, which matters most in exactly the places it is grown.

Because it is one species rather than a family of crops, groundnuts are not divided by nut the way tree nuts are. They are divided by market type, four of them, distinguished by kernel size and shape and by how many seeds sit in a pod, and each type feeds a different product. Runners dominate, roughly four fifths of the US crop, because their kernels are uniform in size and they are what peanut butter is made from. Virginias are the big ones, about 15 percent, the kernel large enough to be roasted and sold in the shell, which is the peanut of the ballpark and the cocktail bowl. Spanish types, about 2 percent, are small, red-skinned, and higher in oil, and they go into candy and salted nuts. Valencias, about 1 percent and grown mostly in New Mexico, carry three or four kernels to a pod and are the sweet ones sold boiled. Botanically the four collapse into two subspecies, the spreading hypogaea (Runner and Virginia) and the upright fastigiata (Spanish and Valencia). One further confusion is worth clearing up: the Bambara groundnut (Vigna subterranea) is a genuinely different plant, an African crop closer to the cowpea that independently evolved the same trick of ripening its pods underground. It is the third most important legume in semi-arid Africa after the peanut and the cowpea, but at roughly 330,000 tonnes it is a rounding error against the 57 million tonnes of true groundnuts.

The map is dominated by two countries. China grows roughly a third of the world crop and India roughly a sixth, so between them they account for more than half of all groundnuts on earth. Behind them come Nigeria at about 8 percent, then the United States and Sudan at about 5 percent each, with Senegal, Myanmar, Argentina, and Brazil making up much of the rest. This is a smallholder crop over most of its range: across West Africa and South Asia it is grown on tiny plots, hand-lifted, and dried in the field, while the American, Argentine, and Brazilian crops are fully mechanised. That split matters more than the tonnages, because it decides which origins can hit an export specification and which cannot.

What happens to the crop divides it in two. Roughly two fifths of world production is crushed for oil, making groundnut one of the significant oilseeds, and most of the rest is eaten directly as confectionery nuts, snack nuts, and peanut butter. Groundnut oil sits behind palm, soybean, rapeseed, and sunflower in the global vegetable-oil table but carries a premium in the kitchens that want it, prized for a high smoke point and for flavour, and it is overwhelmingly an Asian oil: China and India crush most of it and consume most of what they crush. The residue matters too, since peanut meal is a high-protein feed ingredient. So the same pod is simultaneously a snack food, an edible oil, and an animal-feed input, and the crush margin is what decides which one a given lot becomes.

Only a modest slice of the crop crosses a border, because the two biggest producers are also two of the biggest eaters. The export trade that does exist is specialised. Argentina is the quality benchmark, growing high-oleic confectionery-grade kernels around Córdoba almost entirely for export, mostly into Europe. India ships large volumes of kernels and is the leading exporter of groundnut oil. The United States and Brazil are the other mechanised exporters, and the Netherlands appears near the top of the tables as an entrepôt rather than a producer, blanching, grading, and re-exporting through Rotterdam. The quiet oddity is China, which grows more groundnuts than anyone and still imports heavily, largely to feed its crushers.

Groundnuts are the only nut with a real futures market, and it is worth being precise about why. The tree nuts have none: they are too varietal, too handler-dominated, and too origin-specific to standardise. Groundnuts cleared that bar in exactly one place. The Zhengzhou Commodity Exchange listed peanut kernel futures (PK) on 1 February 2021, in 5-tonne lots quoted in yuan per tonne with a 2 yuan tick, physically delivered, and listed in January, March, April, October, November, and December, a calendar with no summer months that tracks the Chinese autumn harvest. The contract exists because China has an enormous domestic crop, a standardisable shelled kernel grade, and a state warehousing system to deliver against. On 12 January 2023 it was added to the list of specified domestic products and opened to overseas traders. It remains a largely domestic Chinese market, but it is a genuine listed price for a crop that has never had one anywhere else.

The gate every groundnut has to pass is aflatoxin, and this crop is the reason the world knows the word. Groundnuts dried in a hot, humid field are an ideal host for Aspergillus flavus, whose toxins are among the most potent natural carcinogens ever identified. The European Union sets the strictest limit in world trade, 4 parts per billion total aflatoxins and 2 parts per billion for aflatoxin B1 in nuts for direct consumption, against looser limits almost everywhere else. That single number reorganises the trade: origins that can reliably hit it sell into the premium confectionery market, and origins that cannot sell into lower-specification markets or send the lot to the crusher instead, because refining strips aflatoxin out of the oil while it stays in the meal. A contaminated crop is not destroyed, it is redirected, and the aflatoxin limit is therefore less a food-safety rule than the mechanism that sorts the world crop into its end uses.

The United States spent most of a century running groundnuts as a controlled market, and the reason it did is a better story than the mechanics. Peanuts are an annual crop, so a farmer commits the acreage a full year before he learns what the price will be, and the whole industry tends to plant into a good price and arrive together at a glut. The New Deal answer, introduced from 1933 and given its peanut-specific form in 1941 under the Agricultural Adjustment Act of 1938, was to stop the cycle at the source by rationing the right to sell. It was also, plainly, an anti-poverty programme: peanuts were a smallholder crop of the rural South at a moment when the rural South was as poor as anywhere in the country. The instrument was a two-tier price support. "Quota" peanuts earned a high support price and could be sold into the domestic edible market; everything above the quota, the "additionals", earned a much lower price and had to be exported or crushed for oil. Americans therefore paid more than the world price for peanut butter, which was the point rather than a side effect.

What killed the programme was that the entitlement outlived the reason for it. Quota was not a payment, it was a capitalised asset attached to land, and it could be inherited and rented, so over sixty years it drifted away from the people actually farming. By 2002 roughly 75,000 people held peanut quota while only about 8,000 farms grew peanuts, and around 60 percent of quota production was grown on rented quota: a poverty programme for Southern smallholders had become rent paid by working farmers to a much larger group of landowners, many of whom had never grown anything. Transfer rules generally blocked quota moving across state and sometimes county lines, so production stayed frozen where the entitlements happened to sit rather than where the crop grew best. The 2002 Farm Bill ended it, buying the quota out at 1,100 dollars a short ton, 55 cents a pound, on 2001 quota levels, payable as a lump sum or five annual instalments of 11 cents and costing roughly 1.3 billion dollars, and moving peanuts onto the same marketing loans, direct payments, and counter-cyclical payments as other row crops. Production promptly relocated to the land that grew peanuts best, consolidating in Georgia and the rest of the Southeast. It is one of the cleanest natural experiments in American farm policy: a supply-control regime removed, and the crop rearranging itself within a few seasons.

No other commodity in this book is also a public-health story, and the groundnut is one twice over. Turkey X disease killed about 100,000 young turkeys in England in 1960; the cause was traced to contaminated Brazilian groundnut meal, and the toxin was named for the mould that made it, Aspergillus flavus toxin, aflatoxin. Four decades later the crop drove the opposite kind of reversal. Peanut allergy had been managed by telling parents to keep peanuts away from infants, until the LEAP trial, published in February 2015, found that early introduction cut peanut allergy at age five by about 86 percent against avoidance. In January 2017 the NIAID issued addendum guidelines telling parents to do the reverse of the previous advice, and on 31 January 2020 the FDA approved Palforzia, an oral immunotherapy and the first treatment ever approved for any food allergy. A crop that spent two decades being banned from schools and aircraft turned out to have been mishandled by the guidance itself.