Monoculture

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

A monoculture potato field

In agriculture, monoculture is the practice of growing one crop species in a field at a time. Monoculture is widely used in intensive farming and in organic farming: both a 1,000-acre cornfield and a 10-hectare field of organic kale are monocultures. Monoculture crops have allowed farmers to increase efficiency in planting, managing, and harvesting, mainly by facilitating the use of machinery in these operations, but monocultures can also increase the risk of diseases or pest outbreaks. Diversity can be added both in time, as with a crop rotation or sequence, or in space, with a polyculture or intercropping (see table below).

Continuous monoculture, or monocropping, where farmers raise the same species year after year, can lead to the quicker buildup and spread of pests and diseases in a susceptible crop.

The term "oligoculture" has been used to describe a crop rotation of just a few crops, as practiced in several regions of the world.[1]

The concept of monoculture can also extend to (for example) discussions of variety in urban landscapes.[2]

Agriculture[edit]

In an agricultural context, the term describes the practice of planting one species in a field.[3] Examples of monoculture include lawns, fields of wheat or corn, or an apple orchard.

Diversity of crops in space and time; monocultures and polycultures, and rotations of both.[4]
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 (intercropping)

Continuous

polyculture

Rotation of polycultures Sequence of polycultures

Note that the distinction between monoculture and polyculture is not the same as between monocropping and intercropping. The first two describe diversity in space, as does intercropping. Monocropping and crop rotation describe diversity over time.

Benefits[edit]

In crop monocultures, each plant in a field has the same standardized planting, maintenance, and harvesting requirements resulting in greater yields and lower costs. When a crop is matched to its well-managed environment, a monoculture can produce higher yields than a polyculture.[5] Modern practices such as monoculture planting and the use of synthesized fertilizers have reduced the amount of additional land needed to produce food,[6] called land sparing.

Risks[edit]

Monocultures of perennials, such as African palm oil,[7] sugarcane,[8][9] tea[10][11] and pines,[12] can lead to soil and environmental problems such as soil acidification, degradation, and soil-borne diseases, which ultimately have a negative impact on agricultural productivity and sustainability.[8] Diverse rotations of crop monocultures can minimize the risk of disease and pest outbreaks.[13] However, the shorter the rotation (fewer crops included) the higher the risk. There are examples of short, two-year rotations selecting for pests that are adapted to such rotations.[14]

Forestry[edit]

In forestry, monoculture refers to the planting of one species of tree.[15] 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.[16] single-species planting also causes trees to be more vulnerable when they are infected with a pathogen, attacked by insects,[17] or affected by adverse environmental conditions.[18]

Residential monoculture[edit]

Lawn monoculture in the United States was historically influenced by English gardens and manor-house landscapes, but its inception into the American landscape is fairly recent.[19] Aesthetics drove the evolution of the residential green areas, with turfgrass becoming a popular addition to many American homes. Turfgrass is a nonnative species and requires high levels of maintenance. However, the drive for its widespread use primarily came from social pressures. At the local level, governments and organizations have begun to take monocultural practices into their own hands (think Homeowner Associations). Various issues related to maintenance of private property have occurred, such as maintaining aesthetics and real estate value. Disagreements in residential maintenance of weeds, lawns, etc, have resulted in civil cases or even direct aggression against neighbors.[19]

Like agriculture, the high levels of maintenance required for turfgrass created a growing demand for chemical management, i.e. pesticides, herbicides, insecticides. A 1999 study showed that in a sample of urban streams, at least one type of pesticide was found in 99% of the streams. One major risk associated with pesticides on lawns include exposure of chemicals into the home through the air, clothing, and furniture which can be more detrimental to children than to the average adult.[19]

Genetic monocultures[edit]

While often referring to the production of the same crop species in a field (space), monoculture can also refer to the planting of a single cultivar across a larger regional area, such that there are numerous plants in the area with an identical genetic makeup to each other. When all plants in a region 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 caused much concern internationally, having already severely affected wheat crops in Uganda and Kenya, and having started to spread in Asia as well.[20] 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 genetic monocultures[edit]

Great Famine of Ireland[edit]

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.

Bananas[edit]

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.[21] 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.[22]

Cattle[edit]

Aerial view of deforested area prepared for monoculture or cattle ranching, near Porto Velho in Rondônia, Brazil, in 2020

The term is also used where a single breed of farm animal is raised in large-scale concentrated animal feeding operations (CAFOs).

Many of today's[when?] livestock production systems rely on just a small number 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 livestock production. In 1990 there were approximately 4 million Holstein cattle in the US, making the affected population around 600,000 animals.[23]

Benefits of genetic diversity[edit]

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 or species.[24] This can help increase crop productivity while simultaneously lowering pesticide usage and risk of exposure.

Monofunctionality[edit]

Monofunctionality is an analogous concept, however it is entirely possible for a monofunctional land bloc to have its function produced by multiple species and so does not suffer from all the same downsides. When industrialisation first came to agriculture and silviculture, monofunctionality was advocated as the ideal due to the significant initial advantages in economic efficiency. However, in the years since opinion has shifted away. In the years since it has become clear that monofunctionality suffers from some of the same downsides as monoculture, specifically forgoing synergies and failing to fulfill the whole range of human needs.[25]

See also[edit]

References[edit]

  1. ^ Compare: Denison, R. Ford (2012). Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture. Princeton: Princeton University Press (published 2016). p. 3. ISBN 9780691173764. Regionally and globally, we practice oligoculture, relying mainly on only a few crops, particularly corn (maize), wheat, and rice.
  2. ^ 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. pp. 15–16. ISBN 9781442696518. [...] 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.
  3. ^ Connor, David J.; Loomis, Robert S.; Cassman, Kenneth G. (28 April 2011). Crop Ecology: Productivity and Management in Agricultural Systems. Cambridge University Press. ISBN 978-1-139-50032-6.
  4. ^ "Ecological Theories, Meta-Analysis, and the Benefits of Monocultures". Retrieved 18 September 2015.
  5. ^ 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. hdl:2027.42/141994. ISSN 0002-9122. PMID 21613148. S2CID 10801536.
  6. ^ G. Tyler Miller; Scott Spoolman (24 September 2008). Living in the Environment: Principles, Connections, and Solutions. Cengage Learning. p. 279. ISBN 978-0-495-55671-8.
  7. ^ Leech, Garry (2009). "The Oil Palm Industry: A Blight on Afro-Colombia". NACLA Report on the Americas. 42 (4): 30–34. doi:10.1080/10714839.2009.11725459. S2CID 157642907.
  8. ^ a b Tayyab, Muhammad; Yang, Ziqi; Zhang, Caifang; Islam, Waqar; Lin, Wenxiong; Zhang, Hua (26 April 2021). "Sugarcane monoculture drives microbial community composition, activity and abundance of agricultural-related microorganisms". Environmental Science and Pollution Research. 28 (35): 48080–48096. doi:10.1007/s11356-021-14033-y. ISSN 0944-1344. PMID 33904129. S2CID 233403664.
  9. ^ 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. 76: 847–860. doi:10.1016/j.landusepol.2018.03.026. S2CID 51932235.
  10. ^ Arafat, Yasir; Ud Din, Israr; Tayyab, Muhammad; Jiang, Yuhang; Chen, Ting; Cai, Zhaoying; Zhao, Hanyu; Lin, Xiangmin; Lin, Wenxiong; Lin, Sheng (2020). "Soil Sickness in Aged Tea Plantation Is Associated With a Shift in Microbial Communities as a Result of Plant Polyphenol Accumulation in the Tea Gardens". Frontiers in Plant Science. 11: 601. doi:10.3389/fpls.2020.00601. ISSN 1664-462X. PMC 7270330. PMID 32547573.
  11. ^ Arafat, Yasir; Tayyab, Muhammad; Khan, Muhammad Umar; Chen, Ting; Amjad, Hira; Awais, Saadia; Lin, Xiangmin; Lin, Wenxiong; Lin, Sheng (August 2019). "Long-Term Monoculture Negatively Regulates Fungal Community Composition and Abundance of Tea Orchards". Agronomy. 9 (8): 466. doi:10.3390/agronomy9080466.
  12. ^ Cordero, Adolfo. "Large scale eucalypt plantations associated to increased fire risk". PeerJ Preprints. doi:10.7287/peerj.preprints.3348v1.
  13. ^ Bullock, D. G. (January 1992). "Crop rotation". Critical Reviews in Plant Sciences. 11 (4): 309–326. doi:10.1080/07352689209382349. ISSN 0735-2689.
  14. ^ Levine, Eli; Spencer, Joseph L.; Isard, Scott A.; Onstad, David W.; Gray, Michael E. (2002). "Adaptation of the Western Corn Rootworm to Crop Rotation: Evolution of a New Strain in Response to a Management Practice". American Entomologist. 48 (2): 94–107. doi:10.1093/ae/48.2.94. ISSN 2155-9902.
  15. ^ Monoculture Forestry
  16. ^ http://www.umich.edu/~nre301/forestry-02.doc[bare URL DOX/DOCX file]
  17. ^ Richardson, David M., ed. (2000). Ecology and biogeography of Pinus. Cambridge, U.K. p. 371. ISBN 978-0-521-78910-3.
  18. ^ "Forestry".
  19. ^ a b c Robbins, Paul; Sharp, Julie (November 2003). "The Lawn-Chemical Economy and Its Discontents". Antipode. 35 (5): 955–979. doi:10.1111/j.1467-8330.2003.00366.x. ISSN 0066-4812. S2CID 154002130.
  20. ^ Vidal, John (19 March 2009). "'Stem rust' fungus threatens global wheat harvest". The Guardian. London. Retrieved 13 May 2010.
  21. ^ "Gros Michel". The banana knowledge platform of the ProMusa network. Retrieved 8 June 2019.
  22. ^ 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. PMID 17766312.
  23. ^ 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. Archived from the original on 6 March 2016. Retrieved 22 October 2015.
  24. ^ 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.
  25. ^ Mander, Ülo; Wiggering, Hubert; Helming, Katharina, eds. (2007). Multifunctional Land Use. Berlin, Heidelberg: Springer. pp. 93–104/xii+422. doi:10.1007/978-3-540-36763-5. ISBN 978-3-540-36763-5. .

External links[edit]