Monoculture

views updated Jun 27 2018

Monoculture

Monoculture refers to the practice of cultivating an agricultural species or tree under conditions where other species are absent or virtually absent. This is done in order to lessen the intensity of competition on growth of the desired crop species.


Selective breeding

The most extreme form of monoculture involves the cultivation of a single genotype of a crop species, to the exclusion of other genotypes and other species. (Note that a single genotype would mean that all of the crop plants are genetically uniform.) Genetic monocultures may be grown in cases where plant breeders have managed to develop uniform strains of plants that are optimally adapted for growth under certain environmental conditions. To practice this extreme type of monoculture, it must be possible to propagate the desired genotype using non-sexual means, such as cuttings, root grafts, or tillers. Seeds , in comparison, are genetically variable, although in intensive agriculture they may be derived from relatively narrow, inbred strains of variable species. Examples of agricultural species that can be propagated asexually and therefore can potentially be grown as genetic monocultures include: (1) sugarcane (Saccharum officinarum), which can be cultivated from rhizome cuttings, (2) bananas (Musa sapientum), which can be propagated from tillers, (3) tea (Thea sinensis), which can be grown from stem cuttings, (4) strawberries (Fragaria x ananassa), which can be cultivated using runners, and (5) apples (Malus pumila), cherries (Prunus avium), and other trees of the rose family, which can be propagated using root grafts.


Tightly controlled environment

Usually, monoculture is practiced as a component of an intensively managed system, in which many environmental factors are controlled to optimize growth conditions for the crop species. For example, to achieve a monoculture of an agricultural plant, only a particular species is actually planted. Other plant species are considered to be weeds, and attempts are made to remove them by hand weeding, manual cultivation, or through the use of a herbicide to which the desired crop species is tolerant, but the weeds are not. In addition, plants grown under monocultural conditions are usually spaced optimally in order to decrease the intensity of competition among individual crop plants. The system may also be fertilized with inorganic nutrients so that nutrient availability does not limit productivity. The monoculture may be irrigated to decrease the importance of water limitations, protected with insecticides against injurious insects , and treated with fungicides to reduce the incidence of diseases. All aspects of the monocultural system are designed toward the optimization of crop yield, to the degree that can be economically and ecologically achieved.


Managed environment

Monocultures in forestry are generally managed less rigorously, because of economic constraints on the intensity of management that can be usefully practiced. A rigorous attempt may be made to only cultivate a single species of tree under plantation conditions. However, smaller plant species may be tolerated in the plantation if they are judged to not excessively interfere with the growth of crop trees, and the system may not be fertilized, irrigated, or otherwise managed as intensively as often occurs in agriculture.

Bill Freedman

Monoculture

views updated May 29 2018

Monoculture

Selective breeding

Tightly controlled environment

Monoculture refers to the practice of cultivating an agricultural species under conditions where other species are absent or virtually absent. This is done in order to lessen the intensity of competition on growth of the desired crop species.

Selective breeding

The most extreme form of monoculture involves the cultivation of a single genotype of a crop species, to the exclusion of other genotypes and other species. Genetic monocultures may be grown in cases where plant breeders have developed strains of plants that are optimally adapted for growth under specific environmental conditions. In this type of monoculture, species are propagated asexually using cuttings, root grafts, or tillers. Examples of agricultural species that can be propagated asexually and therefore can potentially be grown as genetic monocultures include: (1) sugarcane (Saccharum officinarum ), which can be cultivated from rhizome cuttings, (2) bananas (Musa sapientum ), which can be propagated from tillers, (3) tea (Thea sinensis ), which can be grown from stem cuttings, (4) strawberries (Fragaria x ananassa ), which can be cultivated using runners, and (5) apples (Malus pumila ), cherries (Prunus avium ), and other trees of the rose family, which can be propagated using root grafts.

In comparison, planting a single species of seed results in a crop with more genetic variability than would be found in a monoculture. However, in some agricultural crops the seeds they may be derived from very closely-related or inbred strains of a species.

Tightly controlled environment

Usually, monoculture is practiced as a component of an intensively managed system, in which many environmental factors are controlled to optimize growth conditions for the crop. For example, other plant species are considered weeds, and are removed by hand weeding, manual cultivation, or through the use of a herbicide to which the desired crop species is tolerant, but the weeds are not. In addition, crops grown in monoculture are usually spaced optimally in order to decrease the competition among individual plants. The system may also be fertilized with inorganic nutrients so that nutrient availability does not limit productivity. The monoculture may be irrigated to decrease the importance of water limitations, protected with insecticides against insects, and treated with fungicides to reduce the incidence of diseases. All aspects of the monocultural system are designed toward the optimization of crop yield, to the degree that can be economically and ecologically achieved.

Bill Freedman

Monoculture

views updated Jun 08 2018

Monoculture

The agricultural practice of planting only one or two crops over large areas. In the United States, corn and soybean are the only crops grown on most farms in the central Midwest, while on the Great Plains wheat is almost exclusively grown. Although it minimizes farmers' investments in large, expensive implements, the practice exposes crops to the risk of being wiped out by a single predator. This happened with the Irish potato blight of the 1840s and the corn leaf blight of 1970 in the United States, which destroyed millions of acres of corn. Ecologists warn against monoculture's over-simplification of the food chain/web , arguing that complex webs are more stable.

monoculture

views updated May 18 2018

monoculture The growing over a large area of a single crop species (e.g. Triticum aestivum, bread wheat), or of a single variety of a particular species. Monocultures are especially vulnerable to pest and disease infestation, but uniformity of height, development, etc., in a crop facilitates management, especially harvesting. The economic and ecological wisdom of monoculture is widely debated.

monoculture

views updated May 17 2018

monoculture The growing over a large area of a single crop species (e.g. Triticum aestivum, bread wheat) or of a single variety of a particular species. Monocultures are especially vulnerable to pest and disease infestation, but uniformity of height, development, etc. in a crop facilitates management, especially harvesting. The economic and ecological wisdom of monoculture is widely debated.

monoculture

views updated May 29 2018

monoculture See CASH CROP.

monoculture

views updated May 18 2018

monoculture See agriculture.