(NAS Colloquium) Plants and Population Is There Time? (1999) / Chapter Skim
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Global environmental impacts of agricultural expansion: The need for sustainable and efficient practices
Global environmental impacts of agricultural expansion: The need for sustainable and efficient practices
Pages 5995-6000
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From page 5995... ...
These projected changes would have dramatic impacts on the diversity, composition, and functioning of the remaining natural ecosystems of the world, and on their ability to provide society with a variety of essential ecosystem services. The largest impacts would be on freshwater and marine ecosystems, which would be greatly eutrophied by high rates of nitrogen and phosphorus release from agricultural fields.
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From page 5996... ...
The FAO data (1) show that this recent doubling of world food production was accompanied by 6.87- and 3.48-fold increases in the global annual rate of nitrogen and phosphorus fertilization, respectively, by a doubling in the amount of land that was irrigated, and by a 10% increase in the amount of land in cultivation (Fig.
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From page 5997... ...
These nutrients accumulate in a variety of forms in many different sinks (arable soil organic matter, groundwater, freshwater and marine ecosystems and their sediments, nonagricultural ecosystems, atmospheric nitrous oxide) after agricultural application, but the eventual sizes of these pools will depend on biologically and physically driven rates of transfer in and out of these pools (5~.
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From page 5998... ...
Many agricultural crops depend on the pollination services provided by insects, birds, or mammals that live in nearby nonagricultural ecosystems (18~. Similarly, agricultural crops benefit from biocontrol agents, such as parasitic and predatory insects, birds, and bats, that live in neighboring nonagricultural ecosystems and that decrease outbreaks of agricultural pests.
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From page 5999... ...
The plant species diversity of an ecosystem, and its plant species composition, influence its primary productivity (3338~. Total primary productivity increases about 35-70% as plant species diversity increases from one to about 20 species.
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From page 6000... ...
(1997) Nature's Services: Societal Dependence on Natural Ecosystems (Island, Washington, DC)
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