During world War II, bird and bat guano became a hotly contested commodity for it's use in fertilizers and what?

Guano is the polite word for sea bird droppings, and also refers to bat and seal waste. The term came into use in South America to refer to mineral deposits mined from islands off the Peruvian coast. Guano is full of nitrogen, particularly potassium nitrate used for gunpowder, and phosphorus used for fertilizer. Lack of predators allowed birds to poop on these islands for thousands of years, and the lack of rainfall preserved the guano, leaving dried deposits up to 150 feet deep! The War of the Pacific was fought partially over guano mining rights. Chile, Bolivia and Peru all wanted to exploit the minerals of the Atacama Desert on the west coast of South America, which included saltpeter for explosives and guano for fertilizer and gunpowder.