Nutrients213-page10

Nutrients213-page10 - The Columbia River Hydroelectric Power System originated as a means to provide irrigation water for dry land farming The

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Plant Nutrients and Soils - 10 Nitrogen fixation is just one step in making nitrogen available for plants. A series of soil bacteria are involved with providing plants with the soluble form of nitrogen needed for plant growth. Many other plants have nitrogen-fixing associates. To provide adequate nitrogen for rice paddies, an aquatic fern, Azolla , is grown in the rice paddies because it houses a cyanobacterium, Anabaena , in its cells that fixes nitrogen. Alder trees in the Pacific Northwest have bacterial associates (Actinobacteria) for nitrogen fixation, and there are a number of free-living nitrogen fixing bacteria, as well. sporophyte (arrows) in female gametophyte Available water source is also critical to agriculture.
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Unformatted text preview: The Columbia River Hydroelectric Power System originated as a means to provide irrigation water for dry land farming. The benefit of generating electricity came later, and the detriment to salmon was not addressed for several decades. This doesn't even touch on the loss of habitat from flooding caused by dams. Drawing of irrigation water from underground aquifers has seriously depleted water reservoirs. The use of the Colorado River for irrigation has led to severe pollution and insufficient water for its terminus in Mexico. In many parts of the world, parasitic infections abound in irrigation areas. Siltation in dam reservoirs is another concern....
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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