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primary productivity

primary productivity(primary production) The rate at which biomass is produced by photosynthetic and chemosynthetic autotrophs (mainly green plants) in the form of organic substances some of which are used as food materials. Gross primary productivity (GPP) is the total rate of photosynthesis and chemosynthesis, including that portion of the organic material produced which is used in respiration during the measurement period. Net primary productivity (NPP) is the rate of production after some has been lost to plant respiration during the measurement period. Net community productivity is the rate of accumulation of organic material, allowing for both plant respiration and heterotrophic predation during the measurement period. Rates of storage at higher trophic levels are termed secondary productivities. Strictly, the primary production of an ecosystem (as distinct from its productivity, which is a rate) is the amount of organic material accumulated. It is usual to indicate a period of time, however, since otherwise such data have limited value. Thus in practice the terms ‘production’ and ‘productivity’ are often used interchangeably. It is also vital to indicate whether production figures relate to net or gross and to primary or community productivity, or to some portion of these, as with a harvested crop. In the oceans, photosynthesis by phytoplanktonic algae in the upper 100 m (the euphotic zone) accounts for most primary production. Waters of tropical areas are less productive than those of temperate regions, because in tropical areas the water column undergoes no seasonal vertical mixing and so becomes oligotrophic. Areas of upwelling of nutrient-rich deep waters have high productivity.

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"primary productivity." A Dictionary of Ecology. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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"primary productivity." A Dictionary of Ecology. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/primary-productivity-0

primary productivity

primary productivity (primary production) The rate at which energy is stored by photosynthetic and chemosynthetic autotrophs (mainly green plants) in the form of organic substances that may be used as food materials. Gross primary productivity (GPP) is the total rate of photosynthesis and chemosynthesis, including that portion of the organic material produced that is used in respiration during the measurement period. Net primary productivity (NPP) is the rate of production of surplus organic material after some has been lost to plant respiration during the measurement period. Net community productivity is the rate of accumulation of organic material, allowing for both plant respiration and heterotrophic predation during the measurement period. Rates of storage at higher trophic levels are termed secondary productivities. Strictly, the primary production of an ecosystem (as distinct from its productivity) is the amount of organic material accumulated. It is usual to indicate a period of time, however, since otherwise such data have limited value. Thus, in practice the terms ‘production’ and ‘productivity’ are often used interchangeably. It is also vital to indicate whether production figures relate to net primary or net community productivity, or to some portion of these, as with a harvested crop.

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"primary productivity." A Dictionary of Plant Sciences. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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oxygen method

oxygen method An estimation of gross primary productivity by monitoring rates of production of oxygen, the by-product of photosynthesis. In field practice this principle is most often used for productivity measurement in aquatic ecosystems. Paired ‘light and dark’ bottles are filled with water from the required sample depth and suspended at this level for several hours. The dark bottle records oxygen uptake by respiration of phytoplankton and other micro-organisms during the measurement period. Changes in oxygen levels in the light bottle reflect production in photosynthesis as well as loss in respiration. Assuming that respiration rates in the paired bottles are similar, gross primary productivity may be estimated by adding oxygen loss in the dark bottle to the change recorded in the light bottle. The light bottle alone records net community productivity. Net primary productivity estimates are possible only in dense phytoplanktonic communities, e.g. algal blooms in which the oxygen loss resulting from respiration of other micro-organisms is proportionately very small. An important limitation and source of error in the application of the oxygen method to macrophytes arises from the internal storage and utilization of oxygen produced by photosynthesis.

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"oxygen method." A Dictionary of Plant Sciences. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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oxygen method

oxygen method An estimation of gross primary productivity by monitoring rates of production of oxygen, the by-product of photosynthesis. In field practice this principle is most often used for productivity measurement in aquatic ecosystems. Paired ‘light and dark’ bottles are filled with water from the required sample depth and suspended at this level for several hours. The dark bottle records oxygen uptake by respiration of phytoplankton and other micro-organisms during the measurement period. Changes in oxygen levels in the light bottle reflect production in photosynthesis as well as loss in respiration. Assuming that respiration rates in the paired bottles are similar, gross primary productivity may be estimated by adding oxygen loss in the dark bottle to the change recorded in the light bottle. The light bottle alone records net community productivity. Net primary productivity estimates are only possible in dense phytoplanktonic communities (e.g. algal blooms in which the oxygen loss caused by respiration of other micro-organisms is proportionately very small). An important limitation and source of error in the application of the oxygen method to macrophytes arises from the internal storage and utilization of oxygen produced by photosynthesis.

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"oxygen method." A Dictionary of Ecology. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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"oxygen method." A Dictionary of Ecology. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/oxygen-method

Populist Movement

POPULIST MOVEMENT


The Populist Movement is the name given to an important movement of agrarian reformists in the United States during the late nineteenth century. In the 1870s and 1880s U.S. society was generally secure and prosperous. Overall economic growth was steady, and no foreign power threatened U.S. interests. One important area excluded from these positive conditions and developments was agriculture. In the decades after the American Civil War (18611865), the U.S. farmer suffered a precipitous decline in wealth and status.

Prices for key agricultural products such as wheat and cotton experienced dramatic declines as productivity rose and foreign competition increased. Cotton, the backbone of the Southern economy, sold for over 30 cents a pound in 1866. By the early 1890s, however, the price per pound plummeted to six cents. Not surprisingly, farmers in newer settled regions such as Kansas, Nebraska, and the Dakotas were hardest hit because they had recently borrowed start-up money at fixed interest charges. These obligations were increasingly burdensome as agricultural prices continued to drop. The South was hit hardest of all the regions, not having fully recovered from the economic and social dislocations brought on by the Civil War. The basic problem was that the mechanization of agriculture had created an "overproduction crisis." The domestic market could not absorb the increased productivity of the farm. Wheat had sold for $1.60 per bushel in 1865 was going at 49 cents per bushel in 1890.

The decline in the status of the farmer was equally harsh. At the advent of the American republic, Jeffersonian Republicans lauded the farmer as the wellspring of American virtue and prosperity. This idealization of rural life steadily eroded with the growth of U.S. industrialization and urbanization. Cultural and intellectual currents in the city and in the countryside increasingly diverged, and city dwellers began to view the farmer as uneducated, prejudiced, and superstitious.

Before the 1890s rural distress had generated demands for social and economic experiments that would help shield the farmer from the harsh blasts of the market. For example, the Granger Movement of the 1870s produced legislation regulating warehouses, grain elevators, and railroads. It also led to important cooperative experiments in the marketing of farm products and in the purchase of farm machinery, fertilizer, and the like.

The next important wave of populist reformism emerged in the 1890s. Various regional farm groups, known as Farmers' Alliances, took root and grew rapidly. These included the Southern Alliance and the Agricultural Wheel in the south, and the Northwestern Alliance in northern regions. Although these groups found it difficult to unite due to regional differences based on political preferences and economic interests, they shared the belief that agricultural prices were too low, transportation costs were too high, and that the nation's financial system was in need of serious reform. These and other agricultural groups threw themselves into rural politics in 1890 with spectacular results. In the South alone Alliance-sponsored gubernatorial candidates won elections in four states. The Alliance also captured eight southern legislatures. In the West Alliance candidates dominated elections in Kansas and Nebraska and secured important power bases in the legislatures of Minnesota and South Dakota.

Spurred by these victories and by the failure of the Republican and Democratic parties to seriously address their concerns, the rural reformers, along with representatives of industrial labor and professional reformers, organized the People's Party in St. Louis in 1892 and called for a national convention to convene in Omaha in July. The convention was noteworthy for drafting one of the most comprehensive reform programs ever advanced by a major U.S. political party. The platform called for a number of important measures, including the direct election of senators, the adoption of initiative and referendum procedures, civil service reform, nationalization of transportation and communication networks, and a graduated income tax. To combat deflation, the scourge of the rural economy, the platform advocated the free coinage of silver and the liberal printing of paper money. A "subtreasury" plan was also advocated to protect the farmer from downturns in agricultural prices. Under this scheme farmers could hold crops off the market when prices were low and then receive loans from the government secured by crops in storage. To attract support among industrial workers, the platform also advocated an eight-hour workday, pensions, and the restriction of immigration. Indeed, the strategic political goal of the Populist Party was to displace the Democratic Party by forging an alliance between farmers and industrial workers. Equally important, the Populists, at least in principle, attempted to bridge the social gulf between Southern blacks and whites, arguing that shared economic interests were more important than racial differences.

Despite the excitement it generated in the election of 1892, the Populist Party fell painfully short of its political goals. In the election Democrat Grover Cleveland (18931897) garnered 277 votes in the Electoral College to defeat his Republican opponent, Benjamin Harrison (18891893), who received 145 electoral votes. James B. Weaver, the Populist candidate, attracted only 22 electoral votes. Although the Populist Party received over 1,470,000 popular votes in the congressional elections of 1894, it suffered a rapid decline soon after. Part of the reason was that the party was never able to construct a cohesive coalition between its constituent rural components. Nor was it able to forge a significant alliance with industrial labor interests. During their presidential convention in 1896, the Democrats adopted the Populist plank of the free coinage of silver, allowing the Democratic candidate, the firebrand William Jennings Bryan, to appeal to Populist voters. At their own convention in July, 1896, the Populist Party also nominated Bryan, all but fusing with the larger and more influential Democratic Party. A period of rapidly rising agricultural prices also helped seal the fate of the Populist Party.

See also: Farm Policy, Farmers' Alliance, Free Silver, Industrial Revolution, Urbanization


FURTHER READING

Argersinger, Peter. Populism and Politics: William Alfred Peffer and the People's Party. Lexington: University Press of Kentucky, 1974.

Hicks, John D. The Populist Revolt: A History of the Farmers' Alliance and the People's Party. Minneapolis: University of Minnesota Press, 1931.

McMath, Jr., Robert C. American Populism: A Social History, 18771898. New York: Hill and Wang, 1993.

Ostler, Jeffrey. Prairie Populism: The Fate of Agrarian Radicalism in Kansas, Nebraska, and Iowa, 18801892. Lawrence: University Press of Kansas, 1993.

Pollock, Norman. The Humane Economy: Populism, Capitalism and Democracy. New Brunswick, NJ: Rutgers University Press, 1990.

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"Populist Movement." Gale Encyclopedia of U.S. Economic History. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/populist-movement

primary productivity

primary productivity The amount of organic matter synthesized by organisms from inorganic substances. In the oceans, photosynthesis by phytoplanktonic algae in the upper 100m (the euphotic zone) accounts for most primary production. Waters of tropical areas are less productive than those of temperate regions, because in tropical areas the water column undergoes no seasonal vertical mixing. Areas of upwelling of nutrient-rich deep waters have high productivity.

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"primary productivity." A Dictionary of Earth Sciences. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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primary productivity

primary productivity The total amount of organic matter synthesized by the producers (e.g. green plants) of an ecosystem. See productivity.

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"primary productivity." A Dictionary of Biology. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

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