Peruvian Guano
In the 19th century the Inca fertilizer guano (saltpetre) became the most important resource in Peru's modern history, both for its use as a fertilizer and as firepowder. A remarkably ideal habitat and climate in Peru's guano islands allowed the supply of guano to build up over hundreds of years. The nutrient rich Humboldt Current of the coast of Peru once drew thousands of anchovies and other fish, which in turn, attracted thousands of birds. The population of white-breast cormorants, gray pelicans, and piqueros flourished due to a lack of predators. The guano, or bird droppings, the birds left behind was able to retain its nitrate content because of the arid climate. Between 1840 to 1880, Peru sold around 20 million tons of guano, at the rate of hundreds of thousands of tons per year, mostly to Great Britain. Peru earned about 2 billion dollars in profit.
But Peru lost its guano reserves to Chile (backed by the British Empire) in the War of the Pacific. By the late 19th century, 50% of the Peruvian government's revenue was going to pay off loans that been guaranteed with guano sources that Peru lost to Chile - these debts were eventually paid by sending all the remaining guano to France when they were preparing for war. The Germans invented the Haber process shortly after the outbreak of World War I, after which guano became almost worthless.
The remainder of Peru's guano reserves was running out. The government responded by restricting the guano industry to help stabilize the guano supply. The collapse of Peru's bird population after the collapse of the fishery also limits future supply of the fertilizer.
Read more about this topic: Agricultural History Of Peru