Forest soil organic horizon acidification: effects of temperature, time, and solution/soil ratio

Conference · · Soil Sci. Soc. Am. J.; (United States)

OSTI ID:5724496

James, B R; Riha, S J

A forest soil organic horizon (Oe) was acidified with HNO/sub 3/ (0-5 cmol kg/sup -1/) in the laboratory at three solution/soil ratios (10, 50, 100), three temperatures (4, 14, 30/sup 0/C), and for up to 162 h to compare effects of added H/sup -/ on pH, soluble Ca, Al, and C with effects of environmental conditions likely to vary seasonally in the forest floor. Soil suspension pH reached a steady state within 48 h, regardless of quantity of H/sup +/ added, solution/soil ratio, or temperature. Calcium concentrations also reached a steady state with soil solid phases quickly, and additions of H/sup +/ increased quantities of Ca (mmol kg/sup -1/) in solution as did increasing solution/soil ratio. Shaking time and temperature had smaller effects on Ca than did H/sup +/ additions and solution/soil ratio. In contrast, reactions controlling dissolved organic carbon (DOC) and total soluble aluminum (Al/sub t/) were slower than those for pH and Ca. Quantities of DOC and Al going into solution remained nearly constant, so that increasing the solution soil ratio diluted concentrations. Dissolved organic C and soluble Al increased with longer shaking times and higher temperature. The results have implications for designing realistic laboratory experiments on forest floor acidification, for evaluating seasonal and yearly variations in soil solution composition in the field, and in developing accurate and reliable simulation models of H/sup +/ reactions in forest soils.

• Research Organization: Cornell Univ., Ithaca, NY
• OSTI ID: 5724496
• Report Number(s): CONF-871180-
• Conference Information: Journal Name: Soil Sci. Soc. Am. J.; (United States) Journal Volume: 51:2
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID RAIN
ACIDIFICATION
ALKALINE EARTH METALS
ALUMINIUM
ATMOSPHERIC PRECIPITATIONS
CALCIUM
CARBON
CATIONS
CHARGED PARTICLES
DISPERSIONS
ELEMENTS
FORESTS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IONS
KINETICS
METALS
NITRIC ACID
NONMETALS
PH VALUE
QUANTITY RATIO
RAIN
SEASONAL VARIATIONS
SOILS
SUSPENSIONS
TEMPERATURE EFFECTS
TIME DEPENDENCE
VARIATIONS