Photo: UK College of Agriculture, Food & Environment/Flickr
At the core of industrial food production is monoculture—the practice of growing single crops intensively on a very large scale. Corn, wheat, soybeans, cotton and rice are all commonly grown this way in the United States.
Monoculture farming relies heavily on chemical inputs such as synthetic fertilizers and pesticides. The fertilizers are needed because growing the same plant (and nothing else) in the same place year after year quickly depletes the nutrients that the plant relies on, and these nutrients have to be replenished somehow. The pesticides are needed because monoculture fields are highly attractive to certain weeds and insect pests.
Much of industrial monoculture's harvest goes to feed livestock in concentrated animal feeding operations, or CAFOs, where they are fed a high-calorie, grain-based diet, often supplemented with antibiotics and hormones, to maximize their weight gain. Their waste is concentrated and becomes an environmental problem, not the convenient source of fertilizer that manure can be for more diverse, less massively scaled farms.