thumb|Monocultural potato field
In agriculture, monoculture is the practice of growing one crop species in a field at a time. Monocultures increase ease and efficiency in planting, managing, and harvesting crops short-term, often with the help of machinery. However, monocultures are more susceptible to diseases or pest outbreaks long-term
Monocultures appear in contexts outside of agriculture and food production. Grass lawns are a common form of residential monocultures.
Agroecological practices, Monoculture is widely used in intensive farming and in organic farming. 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. Modern practices such as monoculture planting and the use of synthesized fertilizers have reduced the amount of additional land needed to produce food, called land sparing.
{| class="wikitable"
|-
|+Diversity of crops in space and time; monocultures and polycultures, and rotations of both.
! rowspan="3" colspan="3" |
! colspan="3" |Diversity in time
|-
! rowspan="2" |Low
! colspan="2" |Higher
|-
|Cyclic
|Dynamic (non-cyclic)
|-
| rowspan="2" |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.
Environmental impacts
Monocultures of perennials, such as African palm oil, sugarcane, tea and pines, can change soil chemistry leading to soil acidification, degradation, and soil-borne diseases, ultimately having a negative impact on agricultural productivity and sustainability.
As soil health declines, use of synthetic fertilizers on monocultural fields increases, often having negative implications on human health via chemical run-off. For example, excess nitrogen from synthetic fertilizers can leach into ground and surface waters, leading to nitrate contamination of drinking water. This contamination is associated with serious health risks such as methemoglobinemia ("blue baby syndrome") and the formation of carcinogenic compounds such as nitrosamines within the human digestive system.
Agricultural runoff can also degrade aquatic ecosystems through nutrient loading, which subsequently leads to eutrophication harmful algal blooms (HABs). This process can compromise water quality and safety as these blooms produce potent cyanotoxins such as microcystin, which can bioaccumulate in fish and shellfish. Human consumption can ultimately lead to liver damage, neurotoxicity, and gastrointestinal illness.
In addition to soil depletion, monocultures can cause significant reductions in biodiversity due to unavailability of resources, native species displacement, and loss of genetic variation. Following large-scale oil palm plantations in Latin America, research has revealed extensive declines in mammal, bird, amphibian, and pollinator diversity, particularly in Colombia and Brazil. Increasing rotations of crop monocultures or using alternatives agricultural practices can help mitigate the risk of disease and attack.
Social impacts
Environmental consequences of monocultural farming have notable social impacts, commonly concentrated to the reduction of small-scale farmers Notably, the burden of exposure to such pesticides disproportionately affects vulnerable populations including agricultural workers, their families (including children), and residents of nearby communities. These disparities underscore the importance of environmental justice within the One Health framework.
Monoculture practices also influence human diets in ways that can negatively impact human health. The global expansion of monoculture practices has led to the selection of staple crops such as wheat, rice, soy, corn, and sugar on an international level. This has reduced dietary diversity around the world and has promoted calorie-dense but nutrient-poor foods. This change in human dietary patterns has been associated with a decreased intake of essential micronutrients, contributing simultaneously to both nutritional deficiencies as well as overnutrition-related non-communicable diseases such as obesity and type 2 diabetes. Monoculture systems prioritize high-yield crops that can be converted into ultra-processed foods, reinforcing dietary trends towards refined carbohydrates, sugars, and unhealthy fats. Within a One Health perspective, these changes illustrate how agricultural practices can profoundly reduce diversity within the human diet and negatively impact human health outcomes.
Agro-extractivism
Agro-extractivism is a form of extractivism in which foreign territorial, political, and economical dominance over agriculture is motivated by the large-scale production and exportation of agricultural commodities, often in the form of monocultures.
Several monocultures in the Global South, such as sugar and coffee, were first planted in the 1800s following European colonization. These plantations used slave labor, setting a precedent for agriculture being a field dominated by foreign entities in the rest of Latin America and the Caribbean. This social framework has shaped the oppression of Black people and smaller-scale farmers in the face of present-day land acquisition for monocultural use. Land privatization and pressure for monocultural expansion by larger companies takes different forms: silent evictions,. This degradation of soil quality not only jeopardizes long-term productivity, but also reduces the nutritional quality of crops, with the nutrient-poor soil inherently yielding foods with reduced nutrient density. In populations that rely heavily on staple crops, deficiencies in essential micronutrients such as zinc or iron can contribute to malnutrition-related health issues. Within a One Health framework, this illustrates how soil degradation driven by monoculture or similar practices can be directly linked to negative human health outcomes.
Forestry
In forestry, monoculture refers to plantations of one species of tree. In many areas of the world, forest monocultures are planted as an efficient way to produce and harvest timber. Following deforestation, monoculture afforestation has become increasingly popular due to the necessity for ecosystem services, such as mitigating the effects of climate change via carbon sequestration and gas regulation. Eucalyptus, pines, and acacias are examples of popular monocultures being utilized in the tropics and the Global South following rainforest deforestation.
These climate change mitigation strategies may have global benefit but can incidentally incur environmental and human health harm at a local level when viewed through a One Health lens. Tree monoculture often utilizes imported/exotic species such as eucalyptus or pine, ultimately replacing native forests. This disruption can lead to soil depletion and altered water cycles, exacerbating local water and food scarcity issues.. Despite the intentions to provide ecological benefit when it comes to climate change, monoculture forestry can inadvertently compromise environmental, animal, and human health in the regions where is most heavily implemented. This emphasizes the importance of the One Health perspective regarding climate justice and seeking equitable approaches to climate change action.
Environmental impacts
While forest monocultures are efficient ways of producing timber, studies show single-species forests reduce biodiversity, causing declines in forest productivity and native tree, animal, and insect populations over time. The loss of biodiversity in forest monocultures is associated with lower forest resistance to pathogens, attack by insects, and adverse environmental conditions, such as an acceleration of pyrolysis.
Social impacts
Monoculture plantations have been shown to have substantial social impacts on local communities. Forest monocultures have motivated migrations across Latin America due to localized water cycle interference, declining soil health, and changes in resource availability.
Environmental changes caused by monoculture forests are particularly felt among indigenous communities given their reliance and connection to the land while additionally becoming subject to land privatization.
Residential monoculture
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. 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. At the local level, governments and organizations, such as Homeowner Associations, have pressured the maintenance of lawn aesthetics and influenced real estate value. Disagreements in residential maintenance of weeds and lawns have resulted in civil cases or direct aggression against neighbors. Additionally, lawns often replace trees within residential spaces, ultimately reducing the heat mitigation effects offered by a tree's canopy. This can exacerbate urban heat islands, leading to an increase in heat-related illnesses and cardiovascular stress during hot seasons, particularly among vulnerable populations such as the elderly and young children.
Furthermore, turfgrass lawns often require significant irrigation to supplement what local ecosystems can naturally sustain, particularly in arid regions. This leads to an increased pressure on freshwater resources and reliance on external water sources. This elevated water demand contributes to water scarcity and reductions in water quality, as pollutants are concentrated or introduced into the water supply via runoff. These conditions have been linked to reduced sanitation, waterborne disease such as cholera, and dehydration, especially in communities facing limited water access. These dynamics, when viewed from a One Health perspective, help to elucidate how residential land use can strain environmental resources and compromise human health and well-being.
Genetic monocultures
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. 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. 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.
Genetic monoculture in the global food supply chain represents a significant threat to food security. Loss of biodiversity within staple crops results in agricultural practices that are highly vulnerable to pests, pathogens, and environmental stressors. Disease outbreak or climate-related stresses can rapidly spread, leading to widespread crop losses, as seen with the historical examples below. Such famines represent direct threats to human health, with the connections between health and biodiversity better appreciated through the lens of a One Health model.
Historic examples of genetic monocultures
Great Famine of Ireland
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
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, meaning 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 and 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.
Cattle
thumb|Aerial view of [[Deforestation of the Amazon rainforest|deforested area prepared for monoculture or cattle ranching, near Porto Velho in Rondônia, Brazil, in 2020]]
Genetic monoculture can also refer to a single breed of farm animal being raised in large-scale concentrated animal feeding operations (CAFOs). Many 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 traitssuch 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.
Benefits of genetic diversity
Increasing genetic diversity through the introduction of organisms with varying genes can make agricultural and livestock systems more sustainable. By utilizing crops with varying genetic traits for disease and pest resistance, chances of disease outbreak decrease due to the likelihood of neighboring plants having strain-resistant genes. This can aid in increasing crop productivity while decreasing pesticide usage.
Alternatives to monoculture
Alternatives to monoculture include the consultation of agroecology, silvo-pastoral systems, and mixed-species plantations. Despite the recent dominance of GMO monoculture crop rotations of soy, corn, and cotton across the deforested Amazon, many Afrodescendant-run farms in Brazil continue to use traditional practices of agroecology that have the capacity to sustain the local community, environment, and economy.
Silvopasture
Silvopasture is a traditional practice that incorporates the use of various trees and forage in pastures to increase land and livestock productivity. Incorporating other plants in pastures, such as tree legumes, has been shown to enhance pollinator activity, benefitting local biodiversity and food security.