I needed a big book to read on the plane, so I got Charles Mann's 1493 (the successor to the really excellent 1491). There's a whole world-historical theory in the book (file it under "homogenocene" and "The Columbian exchange), but I want to pull out this basket or web of true facts, because they're interesting and indicative. From pp. 272 et seq.:
Unlike mammalian urine, bird urine is a semi-solid substance. Because of this difference, birds can build up reefs of urine in a way that mammals cannot. .... The first European to observe guano carefully was the German polymath Friedrich Wilhelm Heinrich Alexander von Humboldt, who traveled through the Americans between 1799 and 1804. ... Among the thousands of samples Humboldt took back to Europe was a bit of Peruvian gauno. [Analysis] showed that the Chincha guano was 11 to 17 percent nitrogen. ...
A pioneering organic chemist, [Justus von] Liebig was the first to explain plants' dependence on nutrients, especially nitrogen. [From] his treatise Organic Chemistry in its Appllcations to Agriculture and Physiology (1840) [:] "It is sufficient to add a small quantity of quano to soil consisting only of sand and clay, in order to produce the richest crop of maize." ... Sophisticated farmers, many of them big landowners, .., flung down the book, and raced to buy it. Fertility in a bag! Prosperity that could be bought in a store!
It was the beginning of today's input-intensive agriculture -- the practice of transferring huge amounts of crop nutrients from one place to another, distant place according to plans dictated by scientific research.
Interestingly, the guano miners were "imported" from China (at about the same time as the workers who built the western part of the transcontinental railroad in the US) under transport and working conditions comparable to those of the Middle Passage.
NOTE I don't know what the moral of the story is, except that the system(s) of political economy that both support and enmesh us have deep, deep roots.
NOTE Perhaps if I could regard whole islands of recursive bullshit as a resource to be extracted, I'd be a happier human being. (I'm not even sure, at this point, that that's a metaphor....)