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A monocultivated potato field

Monoculture is the agricultural practice of producing or growing a single crop, plant, or livestock species, variety, or breed in a field or farming system 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, widely used both in industrial farming and in organic farming, has allowed increased efficiency in planting and harvesting while simultaneously increasing the risk of exposure to diseases or pests.

Continuous monoculture, or monocropping, where agriculturalists raise the same species year after year,[2] can lead to the quicker buildup of pests and diseases, and then their rapid spread where a uniform crop is susceptible to a pathogen. Monocultures of African palm oil,[3] sugar cane,[4] pines,[5] and soybeans[6] can all be particularly aggressive to the environment. The practice has been criticized[by whom?] for its environmental effects and for having possible long-term effects on agriculture and food supplies. Diversity can be added both in time, as with a crop rotation or sequence, or in space, with a polyculture.

The term "oligoculture" has been suggested[by whom?] to describe a crop rotation of just a few crops, as practiced in several regions of the world.[7]

The concept of monoculture can also extend to (for example) discussions of variety in urban landscapes.[8]

AgricultureEdit

The term is used in agriculture and describes the practice of planting the same cultivar over an extended area. Examples of monoculture include lawns and most fields of wheat or corn. The term is also used where a single breed of farm animal is raised in large-scale concentrated animal feeding operations (CAFOs). In the United States, The Livestock Conservancy was formed to protect nearly 200 endangered livestock breeds from going extinct, largely due to the increased reliance on just a handful of highly specialized breeds.

Diversity of crops in space and time; monocultures and polycultures, and rotations of both.[9]
Diversity in time
Low Higher
Cyclic Dynamic (non-cyclic)
Diversity in space Low Monoculture, one species in a field Continuous

monoculture,

monocropping

Crop rotation

(rotation of monocultures)

Sequence of monocultures
Higher Polyculture, two or more species

intermingled in a field

Continuous

polyculture

Rotation of polycultures Sequence of polycultures

BenefitsEdit

In crop monocultures, each cultivar has the same standardized planting, maintenance and harvesting requirements resulting in greater yields and lower costs. For example, researchers have discovered a native plant to Senegal, called Guiera senegalensis, grown next to millet increased millet production roughly 900 percent. When a crop is matched to its well-managed environment, a monoculture can produce higher yields than a polyculture.[10] In the last 40 years, modern practices such as monoculture planting and the use of synthesized fertilizers have reduced the amount of additional land needed to produce food.[11]

RisksEdit

Annually planting the same crop in the same area depletes the nutrients from the earth that the plant relies on and leaves soil weak and unable to support healthy growth.[12][13] Because soil structure and quality is so poor, farmers are forced to use chemical fertilizers to encourage plant growth and fruit production. These fertilizers, in turn, disrupt the natural makeup of the soil and contribute further to nutrient depletion. Monocropping also creates the spread of pests and diseases, which have to be treated with yet more chemicals. The effects of monocropping on the environment are severe when pesticides and fertilizers make their way into ground water or become airborne, creating pollution.[12][13] Polyculture, the mixing of different crops, increases the likelihood that one or more of the crops will be resistant to any particular pathogen. Studies have shown that planting a mixture of crop strains in the same field can combat disease effectively.[14] Switching to polyculture in areas with disease conditions can 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.[15]

Humans rely heavily on a relatively small number of food crops and farm animals for food. If disease hits a major food crop - as happened during the 19th-century Irish potato famine - food supplies for large populations could come under threat. Maintaining and increasing biodiversity in agriculture could help safeguard world food-supplies.[16]

ForestryEdit

In forestry, monoculture refers to the planting of one species of tree.[17] Monoculture plantings provide greater yields[citation needed] 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.[18] Single-species planting also causes trees to be more vulnerable when they are infected with a pathogen, or attacked by insects,[19] or affected by adverse environmental conditions.[20]

Genetic MonoculturesEdit

While often referring to the mass production of the same species of crop, it can also refer to planting of a single cultivar which has same identical genetic makeups to the plants around them. When all plants in a monoculture are genetically similar, a disease, to which they have no resistance, can destroy entire populations of crops. As of 2009 the wheat leaf-rust fungus occasioned a great deal of worry internationally, having already decimated wheat crops in Uganda and Kenya, and having started to make inroads into Asia as well.[21] Given the very genetically similar strains of much of the world's wheat crops following the Green Revolution, the impacts of such diseases threaten agricultural production worldwide.

Historic Examples of MonoculturesEdit

Irish Potato FamineEdit

In Ireland, exclusive use of one variety of potato, the "lumper", led to the Great Famine of 1845-1849. Lumpers provided inexpensive food to feed the Irish masses. Potatoes were propagated vegetatively with little to no genetic variation. When Phytophthora infestans arrived in Ireland from the Americas in 1845, the lumper had no resistance to the disease, leading to the nearly complete failure of the potato crop across Ireland.

BananasEdit

Until the 1950s, the Gros Michel cultivar of banana represented almost all bananas consumed in the United States because of their taste, small seeds, and efficiency to produce. Their small seeds, while more appealing than the large ones in other Asian cultivars, were not suitable for planting.[22] This meant that all new banana plants had to be grown from the cut suckers of another plant. As a result of this asexual form of planting, all bananas grown had identical genetic makeups which gave them no traits for resistance to Fusarium wilt, a fungal disease that spread quickly throughout the Caribbean where they were being grown. By the beginning of the 1960s, growers had to switch to growing the Cavendish banana, a cultivar grown in a similar way. This cultivar is under similar disease stress since all the bananas are clones of each other and could easily succumb as the Gros Michel did.[23]

CattleEdit

Many of today's livestock production systems rely on just a handful of highly specialized breeds. Focusing heavily on a single trait (output) may come at the expense of other desirable traits - such as fertility, resistance to disease, vigor, and mothering instincts. In the early 1990s a few Holstein calves were observed to grow poorly and died in the first 6 months of life. They were all found to be homozygous for a mutation in the gene that caused Bovine Leukocyte Adhesion Deficiency. This mutation was found at a high frequency in Holstein populations worldwide. (15% among bulls in the US, 10% in Germany, and 16% in Japan.) Researchers studying the pedigrees of affected and carrier animals tracked the source of the mutation to a single bull that was widely used in the industry. Note that in 1990 there were approximately 4 million Holstein cattle in the US, making the affected population around 600,000 animals.[24]

Benefits of Genetic DiversityEdit

While having little to no variety in the genetics of an agricultural system can have drawbacks, increasing genetic diversity by introducing organisms with varying genes can divert them and make the system more sustainable. For example, by having crops with varying genetic traits for disease and pest resistance, there is a much lower chance of having those pests or diseases spread throughout the area. This is because if one crop becomes infected with a particular strain of disease or species of pest, there is a chance that the other plants around it will have genes that protect them from that strain/species.[25] This can help increase crop productivity while simultaneously lowering pesticide usage and risk of exposure.

PolycultureEdit

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 and raising heritage livestock breeds have come about largely as a reaction against monocultures in agriculture.[citation needed]

See alsoEdit

ReferencesEdit

  1. ^ Connor, David J.; Loomis, Robert S.; Cassman, Kenneth G. (28 April 2011). Crop Ecology. ISBN 9781139500326.
  2. ^ "Crop Science - ICSC2004".
  3. ^ Leech, Garry. "The Oil Palm Industry: A Blight on Afro-Colombia". NACLA Report on the Americas. doi:10.1080/10714839.2009.11725459.
  4. ^ Correa-García, Esteban (Summer 2018). "Territorial transformations produced by the sugarcane agroindustry in the ethnic communities of López Adentro and El Tiple, Colombia". Land Use Policy. doi:10.1016/j.landusepol.2018.03.026.
  5. ^ Cordero, Adolfo. "Large scale eucalypt plantations associated to increased fire risk". PeerJ Preprints. doi:10.7287/peerj.preprints.3348v1.
  6. ^ Vieira, I; et al. "Deforestation and threats to the biodiversity of Amazonia". Brazilian Journal of Biology. doi:10.1590/S1519-69842008000500004.
  7. ^ Compare: Denison, R. Ford (2016) [2012]. Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture. Princeton: Princeton University Press. p. 3. ISBN 9780691173764. Retrieved 16 September 2019. Regionally and globally, we practice oligoculture, relying mainly on only a few crops, particularly corn (maize), wheat, and rice.
  8. ^ For example: Gomez, Rafael; Isakov, Andre; Semansky, Matthew (2015). Small Business and the City: The Transformative Potential of Small Scale Entrepreneurship. Rotman-UTP Publishing. Toronto: University of Toronto Press. p. 15-16. ISBN 9781442696518. Retrieved 16 September 2019. [...] the idiosyncratic nature of what an urban main street can offer local residents stands in sharp contrast to the predictable monoculture of contemporary retail development.
  9. ^ "Ecological Theories, Meta-Analysis, and the Benefits of Monocultures". Retrieved 18 September 2015.
  10. ^ Cardinale, Bradley J.; Matulich, Kristin L.; Hooper, David U.; Byrnes, Jarrett E.; Duffy, Emmett; Gamfeldt, Lars; Balvanera, Patricia; O’Connor, Mary I.; Gonzalez, Andrew (1 March 2011). "The functional role of producer diversity in ecosystems". American Journal of Botany. 98 (3): 572–592. doi:10.3732/ajb.1000364. ISSN 0002-9122. PMID 21613148.
  11. ^ G. Tyler Miller; Scott Spoolman (24 September 2008). Living in the Environment: Principles, Connections, and Solutions. Cengage Learning. pp. 279–. ISBN 978-0-495-55671-8. Retrieved 7 September 2010.
  12. ^ a b Haspel, Tamar (9 May 2014). "Monocrops: They're a problem, but farmers aren't the ones who can solve it". New York Times. Retrieved 12 January 2016.
  13. ^ a b What Is Monocropping: Disadvantages Of Monoculture In Gardening
  14. ^ Zhu, Youyong (June 2000). "Genetic diversity and disease control in rice". International Weekly Journal of Science. 406: 718–722. Retrieved 21 March 2019.
  15. ^ "Genetic Diversity and Disease Control in Rice". Archived from the original on 18 November 2011.
  16. ^ Sixth mass extinction of wildlife also threatens global food supplies The Guardian
  17. ^ Monoculture Forestry
  18. ^ http://www.umich.edu/~nre301/forestry-02.doc
  19. ^ Richardson, David M., ed. (2000). Ecology and biogeography of Pinus. Cambridge, U.K. p. 371. ISBN 978-0-521-78910-3.
  20. ^ "Forestry".
  21. ^ Vidal, John (19 March 2009). "'Stem rust' fungus threatens global wheat harvest". The Guardian. London. Retrieved 13 May 2010.
  22. ^ "Gros Michel". The banana knowledge platform of the ProMusa network. Retrieved 8 June 2019.
  23. ^ Schwarzacher, Trude; Heslop-Harrison, J. S. (1 October 2007). "Domestication, Genomics and the Future for Banana". Annals of Botany. 100 (5): 1073–1084. doi:10.1093/aob/mcm191. ISSN 0305-7364. PMC 2759213.
  24. ^ Williams, J.L. (22 October 2015). "The Value of Genome Mapping for the Genetic Conservation of Cattle". The Food and Agriculture Organization of the United Nations. Rome. Retrieved 22 October 2015.
  25. ^ Hajjar, Reem; Jarvis, Devra I.; Gemmill-Herren, Barbara (February 2008). "The utility of crop genetic diversity in maintaining ecosystem services". Agriculture, Ecosystems & Environment. 123 (4): 261–270. doi:10.1016/j.agee.2007.08.003. ISSN 0167-8809.

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