Record Display for the EPA National Library Catalog

RECORD NUMBER: 9 OF 9

Main Title Soil-Mediated Effects of Atmospherically Deposited Sulfur and Nitrogen.
Author Johnson, D. W. ; Reuss, J. O. ;
CORP Author Oak Ridge National Lab., TN. ;Colorado State Univ., Fort Collins. Dept. of Agronomy.;Corvallis Environmental Research Lab., OR.
Year Published 1984
Report Number EPA/600/J-84/120;
Stock Number PB85-106730
Additional Subjects Air pollution ; Soils ; Water pollution ; Sulfur ; Nitrogen ; Air water interactions ; Transport properties ; Leaching ; Plants(Botany) ; Ecology ; Nutrients ; Adsorption ; Acidification ; Sites ; Cations ; Anions ; Reprints ; Acid rain ; Air pollution effects(Plants)
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NTIS  PB85-106730 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 12p
Abstract
The soil mediates both terrestrial and aquatic effects of sulphur and nitrogen deposition in a number of ways. Atmospherically deposited S in excess of biological requirements often accumulates by SO4(-2) adsorption onto Fe and Al oxides in highly weathered soils, causing the release of OH(-1), which can neutralize incoming H+, or an increase in cation exchange capacity. Atmospherically deposited N seldom exceeds biological requirements; when it does NO3(-1) is rapidly leached since no adsorption reactions analogous to those for sulphate exist. When the biological and adsorption capacities are exceeded, cation leaching is accelerated by the mobile SO4(-2) or NO3(-1) anions. The effects of this increased cation leaching must be assessed within the context of natural processes of cation removal such as leaching by internally produced carbonic, organic or (occasionally) nitric acid; natural atmospheric S inputs; and cation export by vegetation harvest. The proportion of individual cations available for leaching is regulated by soil exchange processes and biological demand, both of which tend to minimize the losses of those particular cations most tightly bound and, or, in shortest supply. The ultimate effects of atmospheric S and N deposition will be highly site-specific in nature, depending on both inherent site characteristics and amounts and duration of atmospheric inputs. Thus, benefits of S or N deposition may outweigh negative effects in some sites, whereas the reverse may be true for other sites, making broad, global generalizations hazardous.