Soil emission

Figure 12 Interactions of soil emissions of NO with O3 in plant canopies and NO, uptake by vegetation in determining the net exchange of NO between soil-plant and the atmosphere.

F or NjO, estimates of soil emissions are perhaps slightly more straightforward, simply because so much more information on soil NjO emissions is available. For agricultural soils, estimates as a percentage of fertilizer input have been published " and, for the remaining land use classes listed in Table 5, mean annual emissions from a series of long-term flux measurements are available. The total annual soil NjO emissions for the ElK (27 kt N) are very similar to the annual soil NO emissions. Soils, however, have by far a greater impact on the... 

Davidson, E. A., Keller, M., Erickson, H. E., Verchot, L. V., and Veldkamp, E. (2000). Testing a conceptual model of soil emissions of nitrous and nitric oxide. Bioscience 50, 667-680. 

In this multimedia discharge scenario the overall residence time is 2036 h, which can be viewed as the sum of 5% of the air emission residence time of 632 h, 25% of the water emission residence time of 1153 h and 70% of the soil emission residence time of 2452 h. The overall amount in the environment of 2.04 x 10s kg is thus largely conpolled by the discharges to soil and water. 

Fig. 4.2 Main sources of greenhouse gas emissions in the agricultural sector in 2005 (Smith et al. 2007). Soil emission and enteric fermentation are the main sources and agriculture is assumed to be one of the major sources particularly of nitrous oxide (N20) and methane (CH4)...

Assess extent of impacted soil Emissions considerations O ai... 

In model experiments with catechol, Fe(III), and chloride, and in soil emission studies, it is found that chloroethyne (chloroacetylene) (58) is produced (382). The natural formation of 58 parallels that of vinyl chloride, which is also found in these experiments. The in vitro and in vivo mechanisms are unknown, but the authors propose the path shown in Scheme 3.1 (382). Both chloroethyne and vinyl chloride are emitted from three soil types (coastal salt marsh, peatland, and a deciduous forest). 

Carpi and Iindberg [160] have developed a Teflon dynamic flux chamber for measuring mercury soil emissions. 

Jaegle L. Steinberger L. Martin R.V. and Chance K. (2005). Global partitioning of NOx sources using satellite observations Relative roles of fossil fuel combustion, biomass burning and soil emissions. Faraday Discuss., 130, 407 -423, doi 10.1039/b502128f. 

Wong, E Alegria, H.A. Jantunen, L.M. Bidleman, T.F. Salvador-Figueroa, M. Gold-Bouchot, G. Ceja-Moreno, V. Waliszewski, S.M. Infanzon, R., Organochlorine pesticides in soils and air of southern Mexico Chemical profiles and potential for soil emissions Atmos. Environ. 2008, 42, 7737-7745. 

ENHANCED BIOGENIC SOIL EMISSIONS OF NITROGEN AND CARBON GASES A POSTFIRE EFFECT... 

Levine J. S., Cofer W. R., Sebacher D. L, Winstead E. L., Sebacher S., and Boston P. J. (1988) The effects of fire on biogenic soil emissions of nitric oxide and nitrous oxide. Global Biogeochem. Cycles 2, 445-449. 

Metal Metal production Emissions to air Emissions to soil Emissions to water... 

Johnson D. W. and Lindberg S. E. (1995) The biogeochemical cycling of Hg in forests—alternative methods for quantifying total deposition and soil emission. Water Air Soil Pollut. 80(1-4), 1069-1077. 

Biogenic sources of NO are generally too small to contribute signihcantly to pollution events. Biogenic emissions represent —5% of total NO emissions in the USA (compared to 50% of total VOCs) (Williams et al, 1992). Biogenic NO emissions can be important in intensively farmed regions, where soil emission of NO is enhanced by heavy use of fertilizers. 

Emission values are initially calculated separately as air, water and soil emissions (waste). The calculation includes not only values, for example, from electricity and steam production and transport but also values directly from the processes. The individual values are subsequently aggregated via a weighting scheme to form the overall value for the emissions. Air emissions considered were CO2, SO2, NOx, CH4, hydrocarbons (HC), halogen FfC, NFf3, N2O, FfCl and HF. These are lumped into four impact categories ... 

Nitric oxide emissions from soils on a soybean field, measured by the dynamic chamber system (Li et al., 1999), were compared in Figure 6 with NO fluxes calculated at a 5 meter height utilizing the eddy-correlation method (Gao et al., 1996). In spite of differences in flux magnitudes (note the different scales used), the two show qualitatively similar variations and stmeture with time. The values of NO soil emissions are greater than the NO fluxes at 5 m, which implies that... 

Figure 6- Inter-comparison of NO fluxes at 5 meter height using eddy-correlation technique with NO soil emissions using dynamic chamber technique.

Thornton FC, Bock BR, Tyler DD. 1996. Soil emissions of nitric oxide and nitrous oxide from injected anhydrous ammonium and urea. J Environ Qual 25 1378-1384. 

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