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Air pollution, forest condition and forest decline in Southern Europe: an overview
1998
Bussotti, F. | Ferretti, M. (Laboratorio di Botanica Forestale, Dipartimento di Biologia Vegetale, Piazzale delle Cascine, 28, I-50144 Firenze (Italy))
Chemistry of soil solutions under different kinds of vegetation in the vicinity of a thermal power station
1998
Fernandez-Sanjurjo, M.J. | Alvarez, E. | Vega, V.F. | Garcia-Rodeja, E. (Departamento de Edafologia y Quimica Agricola, Facultad de Biologia, Universidad de Santiago de Compostela, E-15706 Santiago de Compostela (Spain))
Nitrogen deposition in Canada's Boreal Shield: implications for the Kyoto Protocol
1998
Brydges, T.G. (39 Elizabeth Street South, Brampton, Ontario, Canada L6Y 1RR2 (Canada))
Studies of Soils, Soil Water and Stream Water at a Small Catchment near Guiyang, China
1998
Larssen, Thorjørn | Jiling, Xiong | Vogt, Rolf D. | Seip, Hans Martin | Bohan, Liao | Dianwu, Zhao
Acid deposition is considered to be a major environmental problem in China, but information about effects on soils and waters is scarce. To contribute to increased knowledge about the problem a small catchment (about 7 ha) in the outskirts of Guiyang, the provincial capital of Guizhou in south-western China, was instrumented for collection of precipitation, throughfall, soil water and stream water. In addition soil samples have been collected and analyzed for key properties. Median pH in the precipitation is 4.40 (quartiles: 4.19 and 4.77) and the median sulfate concentration 228 µeq/L (quartiles: 147 and 334 µeq/L). The dry deposition of both SO₂ and alkaline dust is considerable. The sum of wet deposition of sulfate and dry deposition of SO₂ has been estimated to about 8.5 gSm⁻²yr⁻¹. The total S-deposition may be somewhat higher due to dry deposition of sulfate and occult deposition. In soil water, SO₄ ²⁻ is the major anion, generally ranging from 300 to 2500 µeq/L in the different plots. Calcium is an important cation, but there is also a considerable contribution of aluminum from the soil. In some of the plots the concentrations of inorganic monomeric aluminum (Ali) are typically between 200 and 400 µm. Potential harmful levels of aluminum and/or high Ali/(Ca²⁺ + Mg²⁺) molar ratios occur in the catchment, but damages to vegetation have not yet been reported. In most cases exchangeable aluminum accounts for between 75 and 95% of the total effective cation exchange capacity (CECE) in the mineral soils. The aluminum chemistry cannot easily be explained by conventional models as the Gaines-Thomas ion-exchange equation or equilibrium with an Al(OH)₃ mineral phase. The stream water is generally less acidic and has considerably lower concentrations of aluminum than the soil water, even though quite acid events have been observed (pH < 4.4). The median pH values are 4.9 and 5.0 in the two first order streams and 6.3 in the dam at the lower boarder of the catchment.
Show more [+] Less [-]Influence of the Soil Solution Composition on Retention and Release of Sulfate in Acid Forest Soils
1998
Kaiser, K. | Kaupenjohann, M.
The potential for sulfate retention is an important soil feature for buffering of atmospheric acid deposition. We studied the effects of increasing additions of different neutral salts and acids on mobilization and retention of SO₄ ²- in acid forest soils. Soils containing up to 11 mmol SO₄ ²- kg⁻¹ were equilibrated with H₂O, NaCl, MgCl₂, and HCl. Release of SO₄ ²- was highest with H₂O and NaCl additions and lowest when HCl was used. Increasing the ionic strength of the added solutions caused decreasing SO₄ ²- concentrations in equilibrium solution. Decreasing pH in equilibrium solution was found to be the reason for the decrease in release. Even when the pH was < 4, the SO₄ ²- release decreased. We assume that this finding resulted from the fact that in the soils studied the SO₄ ²- sorption was controlled by the high contents of Fe oxides/hydroxides.Experiments with Na₂SO₄, MgSO₄, and H₂SO₄ demonstrated that the B horizons already containing high amounts of SO₄ ²- were still able to retain SO₄ ²-. Sulfate retention increased in the order Na₂SO₄ < MgSO₄ < H₂SO₄, which corresponds to increasing H⁺ availability. The higher SO₄ ²- retention along with MgSO₄ compared to Na₂SO₄ may be caused by higher potential of Mg to mobilize soil acidity compared to Na.
Show more [+] Less [-]Effects of simulated acid rain on Pinus densiflora: inhibition of net photosynthesis by the pheophytization of chlorophyll
1998
Shan, Y. (Chinese Academy of Sciences, Beijing (China). Research Center for Eco-Environmental Sciences)
Above-ground sulfur cycling in adjacent coniferous and deciduous forests and watershed sulfur retention in the Georgia Piedmont, U.S.A.
1998
Cappellato, R. (Emory Univ., Atlanta, GA (USA). Human and Natural Ecology Program) | Peters, N.E. | Meyers, T.P.
The effects of acid precipitation and ozone on the ectomycorrhizae of red spruce saplings
1998
Roth, D.R. (Cornell Univ., Ithaca, NY (USA). Dept. of Natural Resources) | Fahey, T.J.
Modelling acidification effects on coniferous forest soils
1998
Eriksson, E. (Uppsala Univ. (Sweden). Dept. of Geosciences)
The life history strategy reflected in morphology, biomass allocation and standing crop of Athyrium distentifolium
1998
Fiala, K. | Tuma, I. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny) | Pande, K.