Thomas Herriot, an astronomer, mathematician, ethnographer and translator, is credited with first introducing the potato into England from Colombia in South America on December 3rd, 1586. It was a fateful event.
The potato was a richer food source than grain. This was because grain stalks would collapse if the head were too heavy, whereas potatoes, grown underground, had no such limits. Not until Norman Borlaug developed short-stemmed grains in his Green Revolution, could cereal crops compete.
Farmers had previously had to leave half their fields fallow to allow the soil to replenish itself, but now they could grow potatoes on the fallow land. The result was an effective doubling of Europe’s food supply. The norm had been that city dwellers could survive lean times by having the wealth and facilities to store grains, but rural dwellers lived constantly on the edge of starvation. Now the potato gave them a calorie source that provided a cushion.
The Europeans copied the South American habit of growing potatoes on relatively poor soil enriched by guano as fertilizer. Guano was imported in bulk as the world’s first intensive fertilizer, and launched the fertilizer industry. When the Colorado beetle also entered Europe to prey on the potato crops, farmers discovered that a form of arsenic (originally found in green paint) was effective against them. Suppliers competed to develop ever more potent arsenic blends, and began the modern pesticide industry
Not everyone took to the potato. The Enlightenment philosopher Diderot was less than enthusiastic in his Encyclopedia. He wrote: “No matter how you prepare it, the root is tasteless and starchy. It cannot be regarded as an enjoyable food, but it provides abundant, reasonably healthy food for men who want nothing but sustenance.”
A problem was building, however, in the widespread reliance on a single crop that lacked genetic variety. The South Americans used many different variants, but the Europeans did not. Theirs was a monoculture vulnerable to pests and parasites. Ireland was particularly exposed because the high caloric yield of the potato had enabled land to be split into smaller parcels of land, each of which could just support a family on potatoes. About 40 percent of the Irish ate no other solid food. The same was true of 10-30 percent of people across a huge swathe of Europe stretching from Ireland to the Urals in Russia.
Disaster struck in the middle of the 19th Century with the appearance of Phytophthora infestans, or Potato Blight. It wiped out up to half the crop in Europe, devastating Ireland the most. A million or more died there of starvation, and two million more migrated, mostly to the United States. This represented a loss of a third or more of the population, which never recovered. Ireland today is the only European country with a population smaller than it had 150 years ago.
The lesson has been noted, and although today there are monocultures in some crops like grains and bananas, where the most successful strains are widely cultivated, other varieties are kept in reserve, ready to be deployed if the dominant strain becomes vulnerable to pests.
The potato brought sustenance that ended the recurrent famines that had plagued Europe, but it taught a lesson about avoiding reliance on a single strain of a single crop. Europeans learned that lesson the hard way.