Critical reviews in environmental science and technology
Paging:
Volume 15 (1985) nr. 1 pages 65-110
Year:
1985
Contents:
Soil formation is an acidifying process that involves dynamic chemical and biochemical equilibria. Chemical weathering involves hydrolysis, hydration, oxidation-reduction reactions, carbonation, and solution of compounds and elements found in the parent materials. The sources of acidity in soils include H2CO3 formed from high CO2 concentrations in the soil atmosphere produced from root and microbial respiration, acidity produced in mineralization of organic N and S and from NH4+-forming fertilizers, organic acids produced from litter decomposition, and addition in precipitation. Additions of acidity in precipitation to soils are insignificant in comparison with the acidity produced in natural processes and by agricultural soil amendments. The pronounced intrinsic buffering capacity provided by soil minerals and organic matter tends to minimize changes in soil pH when acid precipitation is added. The amounts of N and S added by precipitation are beneficial to agricultural, forested, and unmanaged soils. The amounts of other macro- and microelements added to soils by precipitation are insignificant compared with those present in soils.
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