Nitrogen global

Production of nitrogen fertilizer is the largest process whereby human activity mobilizes nitrogen globally (Box 4). 

R. M. Garrels, F. T. Mackenzie, and C. Hunt, Chemical Cycles and the Global Environment Assessing Human Influences, Kaufman, Inc., Los Altos, Calif, 1975 A. J. M. Schoot Uiterkamp, in P. M. Gresshoff, L. E. Roth, G. Stacey, and W. E. Newton, eds.. Nitrogen Eixation Achievements and Objectives, Chapman and Hall, London, 1990, p. 55. 

Table 10. Global Ammonia Capacity and Fertilizer Nitrogen Consumption, 10 t of Elemental Nitrogen ...

Plant nutrient sulfur has been growing in importance worldwide as food production trends increase while overall incidental sulfur inputs diminish. Increasing crop production, reduced sulfur dioxide emissions, and shifts in fertilizer sources have led to a global increase of crop nutritional sulfur deficiencies. Despite the vital role of sulfur in crop nutrition, most of the growth in world fertilizer consumption has been in sulfiir-free nitrogen and phosphoms fertilizers (see Fertilizers). 

Fenner (11) has pointed out that short-lifetime constituents of the atmosphere such as nitrogen oxides, carbon monoxide, and nonmethane hydrocarbons may also play roles related to global warming because of their chemical relations to the longer-lived greenhouse gases. Also, SO, with a very short life interacts with ozone and other constituents to be converted to particulate sulfate, which has effects on cloud droplet formation. 

The continuous interchange of nitrogen between the atmosphere and the biosphere is called the nitrogen cycle. Global estimates are difficult to obtain and there are frequently regional and local impacts which vary greatly from the mean. However, some indication of the size of the various reservoirs of nitrogen in the atmosphere, on land, and in the seas is... 

B. H. SvENSSON and R. Soderlund (eds.). Nitrogen, Phosphorus, and Sulfur-Global Biogeochemical Cycles, SCOPE Report, No. 7, Sweden 1976, 170 pp. also SCOPE Report No. 10, Wiley, New York, 1977, 220 pp, and SCOPE Newsletter 47, Jan. 1995, pp. 1-4. 

Transportation is also the emissions leader. About 75 percent of carbon dioxide emissions and 45 percent of nitrogen oxide emissions come from the transportation sector. If rising levels of CO, are found to be responsible for global warming, and measures are put in place to severely curtail CO, emissions, the measures will have the greatest impact on the transportation sector. 

Power plant emissions result from the comhustion of fossil fuels such as coal, gas, and oil. These emissions include sulfur dioxide (SO,), nitrogen oxides (NO.,), particulate matter, and hazardous air pollutants, all of which are subject to environmental regulations. Another emission is carbon dioxide (CO,), suspected of being responsible for global warming. 

Natural gas will continue to be substituted for oil and coal as primary energy source in order to reduce emissions of noxious combustion products particulates (soot), unburned hydrocarbons, dioxins, sulfur and nitrogen oxides (sources of acid rain and snow), and toxic carbon monoxide, as well as carbon dioxide, which is believed to be the chief greenhouse gas responsible for global warming. Policy implemented to curtail carbon emissions based on the perceived threat could dramatically accelerate the switch to natural gas. 

It is often taken for granted that the oxygen content of the air is nearly constant at ca. 20% of the atmospheric volume, that most of the liquid water on the planet is aerobic (i.e. contains O2), and that most water has pH values relatively close to neutral" (close to 7). However, these circumstances are not mere coincidences but are in fact consequences of the interaction of key global biogeochemical cycles. For instance, the pH of rainwater is often determined by the relative amounts of ammonia and sulfuric acid cycled through the atmosphere, a clear example of interaction between the nitrogen and sulfur cycles. 

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