Polyculture

In agriculture, polyculture is the practice of growing more than one crop species together on the same land at the same time, in contrast to the monoculture that became the dominant approach in developed countries by 1950; traditional examples include the Three Sisters intercropping of maize, beans and squash by Indigenous peoples of Central and North America, the rice-fish systems of Asia, and the complex mixed-cropping systems of Nigeria. The approach can increase total yield since multiple crops are harvested from the same land, reduces the risk of total crop failure, and tends to use resources more efficiently, since interplanted crops suppress weeds and legumes can fix nitrogen, while the added diversity tends to reduce losses to pests and disease and can improve the soil's physical, chemical and structural properties. Its disadvantages include the greater skill polycultures demand to manage, the difficulty of mechanizing a mix of crops with differing sowing depths, spacings and fertilizer or pesticide needs, and the risk that competition between species reduces yields; annual polycultures include intercropping, called companion planting in horticulture, strip cropping, cover cropping and mixed cropping, while perennial polycultures can pair perennial grain or legume crops or, in agroforestry, combine a shade-loving crop such as coffee with trees.