Chemical fertilizer

Historically, fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations, and byproducts of human-nature industries (e.g. fish processing waste, or bloodmeal from animal slaughter). However, starting in the 19th century, after innovations in plant nutrition following Justus von Liebig's discoveries, an agricultural industry developed around synthetically created agrochemical fertilizers. This transition was important in transforming the global food system towards larger-scale industrial agriculture with large crop yields in monocultures.