Evidence of Current Soil Acidification in Spruce Stands in the Vosges Mountains,North-Eastern France

To demonstrate directly soil acidification under spruce stands in the Strengbach catchment, soils from two adjacent stands aged 40 and 90 years were sampled intensively in 1990 and resampled in 1996. Soils already were very acid in 1990. Between 1990 and 1996, soils had experienced a significant decrease in exchangeable Ca2+ and Mg2+ at all depths at the two sites except in the 0-10 cm layer, for which base saturation remained constant. Losses of Ca2+ calculated from a budget study at the same sites and from the comparison of exchangeable stores were similar. In contrast, the loss of Mg2+ from the exchange complex was higher than that computed from the field budget. Various reasons, including most probably uncertainties linked to the extremely low levels of Mg in the ecosystem, may explain this discrepancy. Since 1987, a general decrease of the (Ca2+ + Mg2+)/Al3+ ratio in soil solution was observed at both sites. These results are consistent with present day acidification of soils poor in weatherable minerals under spruce stands in the Vosges Mountains.     

Long Term Changes of Base Cation Pools in Soil and Biomass in a Beech and a Spruce Forest of Southern Sweden

During the past 60 years there has been a considerable decline in pH in mineral soil beneath spruce and beech stands at Tönnersjöheden Experimental Forest in south-west Sweden. In this report an attempt is made to estimate the corresponding declines in base cation pools. The exchangeable storage of Na, K, Ca and Mg in soil, down to 70 cm depth, is calculated to have decreased by 57–60 per cent for beech and by 56–74 per cent for the spruce stands during the period 1927–1984. The calculated cation depletions are compared with estimated nutrient uptake in biomass, base cation release by weathering and leaching losses due to percolation of strong mineral acids and organic anions during the period. The biological acidification may explain about 50–60 per cent of the total losses of base cations from soil, the cation accumulation in biomass then explain 41–43 per cent units for beech and 34–45 per cent units for spruce. The estimated losses of base cations due to acid rain correspond to an amount of cations similar to that accumulated in the spruce biomass during one generation.     

Mid-term trends in acid precipitation,streamwater chemistry and element budgets in the strengbach catchment (Vosges Mountains,France)

In the Vosges Mountains (NE of France), integrated plot-catchment studies have been carried out since 1985 in the Strengbach basin to study the influence of acid atmospheric inputs on surface water quality and element budgets. In this paper, available mid-term time series (1985–1991) have been considered to detect obvious trends, if any, in surface water chemistry and element budgets. Air quality data showed a slight decline for SO₂, whereas NO₂ slightly increased over the period, but these trends are not very significant. This is in agreement with increased N concentration (mainly as NH ₄ ⁺ ) and with the stability of SO ₄ ^2? in open field precipitation. Because of a significant decrease in rainfall amount over the period, only inputs of NH ₄ ⁺ increased significantly whereas H⁺ and SO ₄ ²⁺ inputs declined. In spring and streamwaters, pH and dissolved Si concentration increased mainly as a result of a reduced flow. Na⁺, K⁺, Cl^? and HCO-3~^? concentrations remained stable whereas Ca²⁺, Mg²⁺ and SO ₄ ²⁺ concentrations declined significantly. Only NO ₃ ^? concentration increased significantly in springwaters. The catchment budgets revealed significant losses of base cations, Si and SO ₄ ^2? . These losses decreased over the period. Nitrogen was retained in the ecosystem. However, a longer record is needed to determine whether or not changes in surface water chemistry have resulted from short-term flow reductions or long-term changes in input-output ion budgets. This is specially true with N because the decline in SO ₄ ^2? output was accompanied by N accumulation.     

Evidence of Springwater Acidification in the Vosges Mountains (North-East of France): Influence of Bedrock Buffering Capacity

Investigations on springwater acidity were carried out in the Vosges mountains (north-eastern France). Acid or poorly buffered spring and streamwaters were detected in the same area. The proportion of acid springwaters (pH < 5.6) is about 20% among 220 springs. The springwater pH on granite are equally spread between 5.0 and 6.8 whereas on sandstone a majority of springs is in the range 5.6 to 6.2. As a whole, but mainly on sandstone, from the 1960's to 1990's, the shape of the pH distributions shifts toward greater acidity. In the sandstone area, trends in pH, alkalinity, total hardness (corresponding to divalent cations), sulfate and nitrate were considered over the 30 yr period (1963-1996) in relation to the bedrock chemical composition. Kendall seasonal tau coefficients indicate that decreasing trends were significant for the first three parameters. Linear regression on the smoothed mean value revealed 18 and 90% decrease for pH and alkalinity respectively, for springwaters draining poor-base cation sandstone whereas only 8 and 30% decrease respectively, was observed on clay-enriched sandstone. On silica-enriched sandstone, alkalinity began to decrease in the early 70's as well as pH. Loss of alkalinity only occurred in the early 80's for springs draining clay enriched sandstone. This can be interpreted as a titration process by acid atmospheric inputs of the buffering capacity of weathering and exchange processes in the soils and the catchment bedrock. The nitrate presents an increasing step in the early seventies but possibly as a result of change in analytical technics and/or increase in atmospheric inputs mainly resulting from increase in fertiliser inputs in agricultural areas or in car traffic. Surprisingly no change in sulfate was noticed in any groups of springs probably as a result of the adsorption/mobilisation in the soils. These long-term trends in spring waters (1963-1996) confirmed the soil and streamwater acidification trends already mentioned in this region, in relation to acid atmospheric inputs since no climate nor forestry practice changes have been detected over the period. Moreover, in spite of acid atmospheric input reductions, no recovery can presently be detected.     

Effects of Climate, Land Management, and Sulfur Deposition on Soil Base Cation Supply in National Forests of the Southern Appalachian Mountains

Forest soils having low exchangeable calcium (Ca) and other nutrient base cation (BC) reserves may induce nutrient deficiencies in acid-sensitive plants and impact commercially important tree species. Past and future depletion of soil BC in response to acidic sulfur (S) deposition, forest management, and climate change alter the health and productivity of forest trees. This study used a process model (Model of Acidification of Groundwater in Catchments [MAGIC]) to address a number of questions related to soil BC status for a group of 65 streams and their watersheds in the southern Blue Ridge physiographic province of the southern Appalachian Mountains. Future S deposition to the study watersheds used for the Base Scenario was specified according to proposed reductions in S emissions at the time of this study, representing a reduction of 42 % of ambient S deposition by 2020. Twenty additional simulations were considered, reflecting four alternate S deposition scenarios (6 %, 58 %, 65 %, and 78 % reduction), and various changes in timber harvest, temperature, and precipitation. Base Scenario soil exchangeable Ca and % base saturation showed decreasing trends from 1860 to 2100. Changes in tree harvesting had the largest effect on stream sum of base cations (SBC) and soil BC supply. Each of the scenario projections indicated that median year 2100 soil exchangeable Ca will be at least 20 % lower than pre-industrial values. The simulations suggested that substantial mass loss of soil BC has already occurred since pre-industrial times. Nearly the same magnitude of BC loss is expected to occur over the next 145 years, even under relatively large additional future reductions in S deposition.     

Critical loads of acidity to surface waters in the Vosges massif (north-east of France)

Acid clearwater fishless streams have been identified in the Vosges mountains. In order to evaluate the relatipnships between acidifying factors (such as atmospheric deposition), buffering factors (such as bedrock and soil type), and surface water acidity, an exhaustive survey of streamwater acidity in the Vosges mountains (N-E France) was performed. A network of 11 measurement stations of atmospheric deposition was used to estimate and map deposition over the whole massif (total area 5000 km²). Data on bedrock, soil, superficial deposits, and vegetation were collected from published studies. Sensitive areas as well as acidifying environment factors were derived from the corresponding maps. Over the whole massif, 19% of streams showed baseflow alkalinity below 30 eq.r¹ and 7.5 % were identified as acid (pH < 5.4).=" acid=" streams=" occur=" on=" the=" north-western=" side=" of=" the=" massif=" on=" quartzrich=" sandstone=" and=" acid=" granites.=" in=" each=" of=" these=" areas,=" we=" could=" clearly=" point=" out=" on=" one=" hand,=" the=" negative=" influence=" of=" conifer=" vegetation=" and=" glacial=" soil=" abrasion=" or=" induration,=" and=" on=" the=" other=" hand=" the=" buffering=" effect=" of=" moraine=" deposits.=" a=" corresponding=" range=" of=" critical=" loads=">< 0.2=" to=" 2.0=" keq.=">¹ yr¹) for surface water was calculated using the Steady State Water, Chemistry method (SSWC).     

Nitrogen and Its Effect on Growth, Nutrient Status and Parasite Attacks in Beech and Norway Spruce

In permanent observation plots across Switzerland, nitrogen (N) concentration in the foliage of mature beech has increased by 15% and phosphorus (P) concentrations in beech and mature Norway spruce decreased by 12 and 13% respectively between 1984 and 1995, leading to increased N:P ratios. Modelled N deposition was correlated with stem increment in both beech and spruce, with indications of P limitation in some beech plots. Experimental application of 0-160 kg N ha^-1> yr^-1> over four to five years caused nutrient imbalances in various afforestation plots comparable to those observed in the permanent observation plots. The changes in the trees caused by N treatment led to increased attacks by parasites such as Apiognomonia errabunda, Phomopsis sp., Phyllaphis fagi in beech and Botrytis cinerea, Sacchiphantes abietis and Cinara pilicornis in Norway spruce. The results suggest current N deposition in Switzerland induces significant changes in the forest ecosystem.     

Predicting soil classes with parameters derived from relief and geologic materials in a sandstone region of the Vosges mountains (Northeastern France)

The present study involves the possibility of using geology and relief to map soil classes. We initially focused on two small catchments considered as representative of a 6000-ha forested area overlying a sandstone bed. The catchments differed in the stratigraphic sequence of sandstones, i.e., rich or poor in weatherable minerals. In one, the depleted bedrock was downstream and the rich was upstream, and the converse obtained for the second. Relationships between soil classes and environmental factors were modeled using two discriminant functions corresponding to the two types of stratigraphic sequences found in the catchments. More than 70% of the soil class distribution in small catchments can be explained by the nature of the substratum and attributes derived from a digital elevation model (DEM). These relationships were then applied to a larger region. An automatic catchment delineation was first carried out with the DEM and was then combined with geologic maps. The choice between the two discriminant functions was based on the stratigraphic sequences in each catchment. Predicted soil classes were compared to soil classes conventionally mapped in 1978 at the scale of 1:100,000. The results show that the model reproduced the soil map over 55% of the area studied. Disagreements were due primarily to the existence of superficial deposits not mentioned on the geologic maps and to an altitude effect that is not sufficiently considered in the study of small catchments.     

Hydrochemical budgets of a small forested granitic catchment exposed to acid deposition: The strengbach catchment case study (Vosges massif,France)

Hydrochemical budgets have been obtained for the 3-yr period 1986–89 at Strengbach, a small granitic basin in the Vosges mountains (north-eastern France). Here, the spruce forest shows both yellowing and crown thinning, symptoms of forest decline. Water amount and surface water chemistry were monitored in each ecosystem compartment. Bulk precipitation is acidic. Some pollution episodes occur in winter and early spring, but the annual bulk deposition acidity is rather low. Throughfall however, is much more concentrated, particularly for H⁺ and associated strong acid anions. These inputs come as occult deposits which comprise major ecosystem inputs, as confirmed by the chloride balance for the catchment. Input-output budgets for the catchment indicate a net deficit of base cations, especially calcium. Sulfate also shows a net loss while N budget is well balanced. As the soil exchange capacity is nearly exhausted for base cations, and dominated by H⁺ and Al, the neutralization of incident acid inputs occurs mainly in the weathered bedrock. Silicate weathering processes lead to high losses of cations and of silica. Aluminium hydroxide is precipitated; however, bicarbonate remains very low indicating poorly-buffered surface water.     

Nitrogen Isotopes in Soils and Plants of Tundra Ecosystems in the Khibiny Mountains

Eurasian Soil Science - The isotopic composition of nitrogen in soils and plants may be an indicator of transformation of its compounds and sources of N nutrition of plants. Natural 15N abundance...     

祁连山哈溪林区典型植被土壤阳离子交换量和交换性盐基离子的变化特征

选择祁连山东段哈溪林区的高山灌丛林、祁连圆柏林和青海云杉林3种典型植被土壤为研究对象,研究了其0～100 cm土层土壤阳离子交换量(CEC)和交换性盐基离子(K~+、Na~+、Ca~(2+)、Mg~(2+))的垂直分布规律。结果表明,随土层深度增加,高山灌丛林、祁连圆柏林和青海云杉林的土壤CEC值均不断减小,不同植被按其土壤CEC值大小排序为祁连圆柏林>青海云杉林>高山灌丛林;土壤交换性K~+、Na~+、Ca~(2+)、Mg~(2+)含量随土层深度变化规律各不相同,交换性K~+含量不断减小,交换性Na~+、Ca~(2+)、Mg~(2+)含量没有明显的变化规律;不同森林土壤交换性盐基总量(TEB)变化规律各不相同,按其值大小排序为青海云杉林>祁连圆柏林>高山灌丛林;土壤中交换性K~+、Na~+、Ca~(2+)和Mg~(2+)含量占TEB比例大小为Ca~(2+)>Mg~(2+)>Na~+>K~+;不同森林土壤盐基饱和度(BSP)变化规律亦不相同,按其大小排序为青海云杉林>祁连圆柏林>高山灌丛林。     

大兴安岭北部森林生态系统土壤动物组成与多样性分析

对大兴安岭北部7个代表性森林群落土壤动物进行调查,共捕获湿生土壤动物20216只,大、中小型土壤动物87类,19577只,隶属于4门9纲23目66科。大、中小型土壤动物的优势类群为螨类和节跳虫科,常见类群4类,两者占总捕获量的92.22%。各群落土壤动物的数量和种类组成有一定差异,其中杨落Ⅱ和白桦Ⅲ的数量和种类最多,柳草Ⅶ最少。7个群落共有类群23类,共优类群为螨类中的前气门亚目和中气门亚目,共有的常见类群2类:山跳虫科和线蚓科。7个群落间相似程度均较大,大多为中等相似。各群落土壤动物数量和种类在土壤各层的垂直分布上具有明显表聚性。在多样性分析中,各群落多样性指数H′大小为柳草Ⅶ>白桦Ⅲ>杨落Ⅱ>落沼Ⅳ>樟子松Ⅵ>桦杜Ⅰ>蒙古栎Ⅴ。大部分群落多样性指数的动态变化是8月>6月>10月。     

Caracterisation micromorphologique et hydrodynamique des niveaux structures par le gel Quaternaire dans les formations superficielles du bassin-versant de la Fecht (Vosges, France)

Detritic superficial formations, covering most of the slope in Fecht basin (Vosges, France), are deposited in the course of Quaternary cold periods. A detailed study on these deposits give evidence of structures directly or indirectly associated with the action of deep freezing and thawing: laminated structure, compact laminated structure with silt caps, stratified displaced granitic regolith, gelifluction deposits, etc. The cryogenic structures are generally well conserved, unless they are submitted to actual pedogenesis. Their influence on the hydrodynamic properties of the slope deposits is noteworthy: according to discriminant analysis, hydric comportment in this porous medium is largely influenced by the herited cryogenic structures. These structures, conserved under the actual soil, present high bulk density, weak water retention and low saturated hydraulic conductivity which are clearly contrasted to the values obtained in the upper part of the profile submitted to the destruction by pedogenesis. Particularly displaced granit regoliths, because of the included few permeable bands of fine material, react as a zone that hinders hydric transfers and induces lateral flows in slope deposits. This fact plays an important role in stationnal hydric budget.     

The Impact of Road De-Icing Salts (NaCl) on Colloid Dispersion and Base Cation Pools in Roadside Soils

The maintenance of safe-drivingconditions in snow and ice-affected areas in thewintertime includes the use of sodium chloride (NaCl)as de-icing salts. In this study, the impact of NaClon soil-colloid mobilisation and exchangeablebase-cation leaching has been evaluated. The chemistryof groundwater samples below an infiltration trenchfor highway runoff and leachate from column studiessuggested that soil-colloid mobilisation had occurred,as the exchangeable sodium (Na) concentration and theelectrical conductivity (EC) in the groundwater/columnleachate reached the threshold values for colloiddispersion. Generally, samples with no dispersionproblems had high Na and calcium (Ca) concentrations,suggesting that the initial effect of the de-icingsalt was to stabilise the colloids. In the columnstudy there was a good agreement between the degree ofcolloid dipersion problems and lead (Pb) concentrationwhen the pH value was above 7.0. Significant negativecorrelations between Na/CEC (cation exchange capacity)and Ca/CEC in roadside soils from three sitesindicated that Na preferentially displaces Ca from theexchange sites. However, the groundwater dataindicated that Na ions also displace potassium (K) andmagnesium (Mg). A positive effect of NaCl seen at onesite was an increase in the K concentration, which ishighly likely an effect of Na ions displacing fixed Kbetween the layers of 2:1 type clay minerals. In soilslacking these types of clay minerals, severe Kshortage may result from a high plant demand combinedwith the low K concentration in the readily availablefractions in the original soil and a highsusceptibility to leaching. The most significantimpact on soil exchange processes was found to occurwithin 6 m from the road.     

大兴安岭北部森林生态系统土壤动物的功能类群及其生态分布

对大兴安岭北部塔河县7个森林群落的土壤动物进行研究,将该区土壤动物划分为腐食性、植食性和捕食性动物三个功能类群,无论个体数量还是生物量,腐食性动物所占比例都最大,而植食性和捕食性动物所占比例较小。土壤动物各功能类群在组成、个体数量和生物量等方面均具有相对稳定性,并在一定程度上反映了环境质量。土壤环境条件优越的群落,腐食性动物的个体数量及生物量所占比例相应较大。与小兴安岭森林土壤动物相比,大兴安岭地区腐食性动物所占比例减小,植食性和捕食性动物所占比例相应增加。各地区的共有类群反映了大环境的相似程度,而特有类群则反映出各自局地环境的特殊性,它们对生态系统具有指示作用。     

Aluminium chemistry in two contrasted acid forest soils and headwater streams impacted by acid deposition,Vosges mountains,N.E. France

Al chemistry was studied in two acidic watersheds, one with a podzol, the other with an acid brown soil, in the Vosges mountains (N.E. France), by analysing both leaching and centrifugation soil solutions and spring waters over 3 yr. In the podzol, Al was mobilized in the eluvial horizons under the predominant influence of organic acidity, then leached down the profile as organic and F-bound Al. Strong undersaturation with respect to proto-imogolite and imogolite showed that the proto-imogolite theory of podzolization could not apply. Al was transferred from the soil to spring water mostly as Al³⁺ and Al-F. Al³⁺, as well as additional minor species (AlOH²⁺, AlSO₄ ⁺), originated from the redissolution of the top of the spodic horizons under the influence of both soil solution acidity and the occurrence of mobile anions derived from atmospheric deposition. Conversely, in the acid brown soil, Al mobilization was regulated by nitrate and occurred mainly as Al³⁺. Most of Al was retained in the deep soil and only traces of monomeric Al reached spring water. In the podzol eluvial horizons, soil solutions were undersaturated with respect to all relevant mineral phases and their chemical composition agree with the concept of a mobilization of Al from the solid soil organic Al and a control of Al³⁺ activity by complexation reaction with the solid and soluble soil organic matter and F. In the acid brown soil, soil solutions were found to be in equilibrium with natural alunite, and the formation of this mineral, if confirmed, would account for the occurrence of 'open' vermiculites instead of the expected hydroxy-Al interlayered vermiculites. Al solubility control in surface water of both watersheds remains unclear. The Al-F species in both watersheds and the likely control of Al solubility by alunite in the acid brown soil emphasize the influence of acid deposition on Al chemistry in acid watersheds.     

Chemical Composition of Rainwater Near Two Historical Monuments The Thann Collegiate (Alsace,France) and the Tours Cathedral (Indre et Loire,France)

In the present study, included within the framework of a Franco-German Research Program for Conservation of HistoricalMonuments, the chemical composition of rainwater was investigated in Thann (Alsace, France) and in Tours (Indre etLoire, France) between 1992 and 1993. A total of 78 and 24samples, respectively, were collected, near the Thann collegiateand the Tours cathedral on a weekly basis and analysed for Cl^-, NO₃ ^-, SO₄ ^2-, Na⁺, NH₄ ⁺, K⁺, Mg²⁺ and Ca²⁺. Results showpH ranged from 3.60 to 6.58 and from 5.49 to 7.01 for Thann andTours, respectively. In Thann, SO₄ ^2- is the major anion and rainwater acidity is neutralised by compounds ofterrigenic origin which come from the soil of the upper Rhinevalley (Ca²⁺; ‘loess’) and the potash mines of Alsace. In Tours, SO₄ ^2- is also the major anion and the acidity is neutralised partially by atmospheric ammonia and partially by compounds of terrigenic origin and by dust fromthe erosion of the cathedral and the works of restoration, in the form of CaCO₃.     

Diagnostics,Genesis, and Localization of Pedosediments within a Small Catchment (Central Russian Upland)

Eurasian Soil Science - Results of a detailed analysis of pedosediments—sediments composed of transported material of soil humus horizons—are discussed. Five main morphological features...     

Seasonal Dynamics of Biogeochemical Proton and Base Cation Fluxes in a White Birch Forest in Hokkaido, Japan

Biogeochemical proton and base cation fluxes in a 30-year old white birch forest composed of Dystric Cambisols in northern Hokkaido, Japan were estimated using data on atmospheric deposition (AD), throughfall (TF), stemflow (SF), and discharge from soils (DS) and plant uptake (UP) from early June to November 1999. In the monitoring period, proton flux was 0.20kmol_cha^?1 for AD, 0.07 for TF+SF, and 0.03 for DS, indicating that atmospheric acid input was neutralized through plant and soil. Base cation flux was 1.29 for AD, 1.23 for TF+SF, and 0.99 for DS and plant base cation uptake was 2.14, indicating that the soil was the major source of base cation for plant. However, these seasonal fluxes showed various trends. Cumulative base cation flux in TF+SF showed constant increase trend during the whole period, which was similar to AD. Proton flux in AD jumped once just after a heavy rain of 255mm for 8 days at the end of July. Trends for the proton and base cation fluxes in TF plus SF were similar to that of AD. Although proton and base cation fluxes of DS were not found until middle July because of vegetation uptake and no flow, both fluxes increased suddenly after the heavy rain in July. After August, the base cation and proton fluxes in the DS increased continuously, due to the lack of plant uptake and intermittent rainfall. In this study, it is clear that plant activity and water flow are very important driving force for seasonal dynamics of biogeochemical cycling.