1493_ Uncovering the New World Columbus Created - Charles C. Mann [121]
Centuries ago Andean Indians discovered that depleted soils could be replenished with guano. Llama trains carried baskets of Chincha guano along the coast and perhaps into the mountains. The Inka parceled out guano claims to individual villages, levying penalties for disturbing the birds during nesting or taking guano allocated to other villages. Blinded by the shine from Potosí silver, the Spaniards paid little attention to conquered peoples’ excremental practices. The first European to observe guano carefully was the German polymath Friedrich Wilhelm Heinrich Alexander von Humboldt, who traveled through the Americas between 1799 and 1804. A pioneer in botany, geography, astronomy, geology, and anthropology, Humboldt had an insatiable curiosity about everything that crossed his path, including the fleet of native guano boats that he saw skittering along the Peruvian coast. “One can smell them a quarter of a mile away,” he wrote. “The sailors, accustomed to the ammonia smell, aren’t bothered by it; but we couldn’t stop sneezing as they approached.” Among the thousands of samples Humboldt took back to Europe was a bit of Peruvian guano, which he sent to two French chemists. Their analysis showed that Chincha guano was 11 to 17 percent nitrogen—enough to burn plant roots if not properly applied. The French scientists touted its potential as fertilizer.
Few took their advice. Supplying European farmers with guano would involve transporting large quantities of excrement across the Atlantic, a project that understandably failed to enthuse shipping companies. Within several decades, though, the picture changed. Agricultural reformers throughout Europe had begun to worry that the ever-more-intense agriculture necessary to feed growing populations was exhausting the soil. As harvests leveled off and even decreased, they looked for something to restore the land: fertilizer.
At the time, the best-known soil additive was bone meal, made by pulverizing bones from slaughterhouses. Bushels of bones went to grinding factories in Britain, France, and Germany. Demand ratcheted up, driven by fears of soil depletion. Bone dealers supplied the factories from increasingly untoward sources, including the recent battlefields of Waterloo and Austerlitz. “It is now ascertained beyond a doubt, by actual experiment upon an extensive scale, that a dead soldier is a most valuable article of commerce,” remarked the London Observer in 1822. The newspaper noted that there was no reason to believe that grave robbers were limiting themselves to battlefields. “For aught known to the contrary, the good farmers of Yorkshire are, in a great measure, indebted to the bones of their children for their daily bread.”
From this perspective, avian feces began to seem like a reasonable item of commerce. A few bags of guano appeared in European ports in the mid-1830s. Then Justus von Liebig weighed in. A pioneering organic chemist, Liebig was the first to explain plants’ dependence on nutrients, especially nitrogen. In his treatise Organic Chemistry in Its Application to Agriculture and Physiology (1840), Liebig criticized the use of bone fertilizer, which has little nitrogen. Guano was another story: “It is sufficient to add a small quantity of guano to a soil consisting only of sand and clay, in order to procure the richest crop of maize.” Liebig was enormously respected; he was an avatar of the Science that had brought new, productive crops like the potato and maize, and new ways of thinking about agriculture and industry. Organic Chemistry was quickly translated into multiple languages; at least four English editions appeared. Sophisticated farmers, many of them big landowners, read Liebig’s encomium to guano, flung down the book, and raced to buy it. Yields doubled, even tripled. Fertility in a bag! Prosperity that could be bought in a store!
Guano mania took hold. In 1841, Britain imported 1,880 tons of Peruvian guano, almost all of it from the Chincha Islands; in 1843, 4,056 tons; in 1845, 219,764 tons. In forty years, Peru exported about 14 million