Monoculture

Monoculture is the agricultural practice of producing or growing a single crop or plant species in a field at a time. Polyculture, where more than one crop is grown in the same space at the same time, is the alternative to monoculture.^[1] Monoculture is widely used in modern industrial agriculture and its implementation has allowed for increased efficiencies in planting and harvest.

Continuous monoculture, or monocropping, where the same species is grown year after year,^[2] can lead to the quicker buildup of pests and diseases, and then rapid spread where a uniform crop is susceptible to a pathogen. This is in contrast to crop rotation, where monocultures of various crops are rotated on a field over time. Oligoculture has been suggested to describe a crop rotation of just a few crops, as is practiced by several regions of the world.^[3]

The term is frequently borrowed for other uses, such as raising one species of livestock in a farm, or even in fields other than agriculture to describe any group dominated by a single variety, e.g. in the field of musicology to describe the dominance of the American and British music-industries in Western pop music, or in the field of computer science to describe a group of computers all running identical software.

A monocultivated potato field

Land use

The term is mostly used in agriculture and describes the practice of planting crops with the same patterns of growth resulting from genetic similarity. Examples include wheat fields or apple orchards or grape vineyards. These cultivars have uniform growing requirements and habits, resulting in greater yields on less land because planting, maintenance (including pest control), and harvesting can be standardized. This standardization results in less waste and loss from inefficient harvesting and planting. It also is beneficial because a crop can be tailor-planted for a location that has special problems – like soil salt or drought or a short growing season.

Monoculture produces great yields by utilizing plants' abilities to maximize growth under less pressure from other species and more uniform plant structure. Uniform cultivars are able to better use available light and space, but also have a greater drain on soil nutrients. In the last 40 years, modern practices such as monoculture planting and the use of synthesized fertilizers have greatly reduced the amount of land needed to produce much higher yielding crops.^[4] A huge problem with growing any crop in a monoculture is that once the land has been used to agriculture for a single species, soil fertility diminishes greatly.^[5]

Forestry

In forestry, monoculture refers to the planting of one species of tree.^[6] Monoculture plantings provide great yields and more efficient harvesting than natural stands of trees. Single-species stands of trees are often the natural way trees grow, but the stands show a diversity in tree sizes, with dead trees mixed with mature and young trees. In forestry, monoculture stands that are planted and harvested as a unit provide limited resources for wildlife that depend on dead trees and openings, since all the trees are the same size; they are most often harvested by clearcutting, which drastically alters the habitat. The mechanical harvesting of trees can compact soils, which can adversely affect understory growth.^[7] Single-species planting of trees also are more vulnerable when infected with a pathogen, or are attacked by insects,^[8] and by adverse environmental conditions.^[9]

Lawns and animals

Examples of monoculture include lawns and most field crops, such as wheat or corn. The term is also used where a single species of farm animal is raised in large-scale concentrated animal feeding operations (CAFOs).

Disease

Monocultures used in agriculture are usually single strains that have been bred for high yield and resistant to certain common diseases. Since all plants in a monoculture are genetically similar, if a disease strikes to which they have no resistance, it can destroy entire populations of crops. Polyculture, which is the mixing of different crops, has natural variation and a likelihood that one or more of the crops will be resistant to any particular pathogen. Studies have shown planting a mixture of crop strains in the same field to be effective at combating disease.^[10] Ending monocultures grown under disease conditions by introducing crop diversity has greatly increased yields. In one study in China, the planting of several varieties of rice in the same field increased yields of non-resistant strains by 89% compared to non-resistant strains grown in monoculture, largely because of a dramatic (94%) decrease in the incidence of disease, making pesticides less necessary.^[11] There is currently a great deal of international worry about the wheat leaf rust fungus, that has already decimated wheat crops in Uganda and Kenya, and is starting to make inroads into Asia as well.^[12] As much of the world's wheat crops are very genetically similar following the Green Revolution, the impacts of such diseases threaten agricultural production worldwide.

Polyculture

The environmental movement seeks to change popular culture by redefining the "perfect lawn" to be something other than a turf monoculture, and seeks agricultural policy that provides greater encouragement for more diverse cropping systems. Local food systems may also encourage growing multiple species and a wide variety of crops at the same time and same place. Heirloom gardening has come about largely as a reaction against monocultures in agriculture.

See also

• Crop diversity
• Biodiversity
• Dust Bowl
• Genetically modified organism
• Gros Michel bananas
• Heirloom plant
• Kil'ayim (prohibition)
• Neglected and underutilized crop
• Permaculture
• Seed bank
• Three Sisters

References

External links

Look up monoculture in Wiktionary, the free dictionary.

• Monoculture and disease