Other forms: monocultures
When a farmer grows just one crop — like wheat, or corn — it's called monoculture. On big, industrial farms, monoculture tends to be the current mode of choice (for better or for worse!).
Monoculture makes it easier for farms to produce huge amounts of a crop, and the simplicity of planting and harvesting, as well as pest control, makes things easier for workers and farmers. However, monoculture has become controversial because it hurts the quality of the soil over time, as well as allowing the fast and devastating spread of pests or disease. Polyculture, when many different crops are planted together, is healthier for the environment. Mono means "one" in Greek, while poly means "many."