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Sources of Excess Nitrogen
Sources of the excess nitrogen include increased use of nitrogen fertilizer
and nitrates produced from fossil fuel combustion. It is estimated that humans
produce 60% of the fixed nitrogen deposited on land each year, which is far more
than can be absorbed by agricultural and natural ecosystems. These changes
reduce biological diversity by preferential growth and possible ecosystem
takeover by species that thrive in high nitrogen
levels.
Nitrogen that is not used by plants may be immobilized in the soil by mineralization or other processes that prevent its translocation. Nitrogen that is not used by plants or immobilized in place will contribute to leaching - loss of nitrogen to ground water or surface water.
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