德国东部扬尘沉积山坡上松林中土壤的性质

Physical, chemical, and microbial properties of forest soils subjected to long-term fly ash depositions were analyzed in spruce （Picea abies （L.） Karst.） stands of eastern Germany on three forest sites along an emission gradient of 3 （high input）, 6, and 15 km （low input） downwind of a coal-fired power plant. Past emissions resulted in an atypical high mass of mineral fly ash constituents in the organic horizons at the high input site of 128 t ha^-1 compared to 58 t ha^-1 at the low input site. Magnetic susceptibility measurements proved that the high mineral content of the forest floor was a result of fly ash accumulation in these forest stands. Fly ash deposition in the organic horizons at Site I versus III significantly increased the pH values, effective cation exchange capacity, base saturation and, with exception of the L horizon, concentrations of mobile heavy metals Cd, Cr, and Ni, while stocks of organic C generally decreased. A principal component analysis showed that organic C content and base status mainly controlled soil microbial biomass and microbial respiration rates at these sites, while pH and mobile fractions of Cd, Cr, and Ni governed enzyme activities. Additionally, it was hypothesized that long-term fly ash emissions would eventually destabilize forest ecosystems. Therefore, the results of this study could become a useful tool for risk assessment in forest ecosystems that were subjected to past emissions from coal-fired power plants.     

Soil macrofaunal response to forest conversion from pure coniferous stands into semi-natural montane forests

We studied the response of the macrofauna to forest conversion from pure coniferous stands into semi-natural montane forests in the southern Black Forest (Germany). The investigation was carried out by comparing existing stands that represent the four major stages of the envisaged conversion process. Major results are: (i) environmental parameters indicate a significant alteration of the soil environment, (ii) neither an overall change nor a clear trend in macrofaunal richness and abundance could be established, and (iii) the data for the different taxa suggest specific responses to the conditions of the individual conversion stages. In general, saprophagous taxa seem to be mainly driven by alterations of the resource base (litter quality, microbial parameters) while predatory taxa tend to respond to changes at the consumer level. Associated alterations in the functional structure occurred for macroengineers (earthworms), primary consumers (diplopods, isopods) as well as a wide range of predators. These changes could partly be explained by changes in environmental conditions that did not follow a gradual adjustment during the conversion process. One essential step is the shift from an organic layer composed of low-quality coniferous litter that is dominated by fungi to a litter layer with higher quality food sources. Within this framework, the specific response of the macrofauna is modulated by factors such as differences in structural features of the ground vegetation and availability of woody litter in a stage-specific way. Since the response of the macrofauna depended far less on site conditions than any of the other environmental factors, this invertebrate group may be used as a valuable indicator of the changes associated with different stages of the conversion process. As long as no dramatic change of soil conditions – in particular pH – occurs, however, no fundamental restructuring of the soil community is to be expected.     

重庆缙云山典型林分土壤结构分形特征

 为了解长江三峡库区森林土壤的物理性质,运用分形原理,研究重庆缙云山4种典型林分林地土壤分形特征,建立土壤结构分维与土壤性质预测模型,运用弹性分析与边际分析,探讨土壤结构分形变化与土壤性质变化的关系。研究表明:土壤机械组成分维、微团聚体组成分维和孔隙组成分维可作为评价土壤结构的指标。不同林分林地土壤颗粒机械组成分维值为2.7～2.9,土壤微团聚体组成分维为2.5～2.8,土壤孔隙组成分维为2.3～2.8。从质地、微团聚体组成和孔隙组成来看,常绿阔叶灌丛土壤结构要明显优于其他林地土壤,而楠竹林最差。不同林分及农地土壤的微团聚体组成、机械颗粒组成和孔隙组成分维与土壤性质存在较明显相关关系,相关系数都在0.5以上。由弹性系数和边际量可以看出,机械分维的影响要大于微团聚体分维和孔隙组分维。这对进一步探讨分形学在土壤结构与土壤性质的应用方面有重要的意义。     

Soil bulk density corrections for providing a better relationship with root growth in gravelly soil

Abstract

Bulk density of a Tifton (Plinthitic Paleudult; fine loamy, siliceous, thermic) soil containing 5.8 to 11.0% of the sample weight as pebbles was 0.06–0.12 g/cc lower when corrections were made for presence of pebbles or concretions. A method for determining the bulk density of the soil matrix between pebbles or concretions is outlined. After adjustment, the bulk density at which root penetration was inhibited in this soil closely approximated that for soils which do not contain concretions. The proposed procedure reflects more nearly how bulk density changes where plant roots are growing than previously published procedures do.     

Fertilization of declining conifer stands in the vosges and in the French Ardennes

Twenty fertilization experiments were set up in 1985 and 1986 in the Vosges mountains, using mostly calcareous or Mg fertilizers, in order to verify whether fertilization can attenuate defoliation and yellowing recently recorded in Silver fir and Norway spruce. In the Ardennes, a fertilization experiment set up in Norway spruce stands prior to the appearance of yellowing was assessed. In these areas, the total acid deposition is about 2 kg eq H⁺ ha^–1 yr^–1. Nitrogen deposition is much more important in the Ardennes (52 kg N ha^–1 yr^–1 in form of wet and dry deposition) than in the Vosges (16 kg N ha^–1 yr^–1). The results in the eight adult stands showed no uniform reaction to the treatments. Spontaneous improvement, further deterioration independently of the treatment, as well as a positive reaction to fertilization were observed. Additional N or P fertilization sometimes had a beneficial effect on Ca or Mg treatments. The selection of the stands with the best response turns out to be difficult, as the nutrient contents of needles alone seem not to be a satisfactory criterion for selection. Young plantations reacted positivley to the treatments. Soluble Mg fertilizer leads to an immediate response. Low solubility Ca-Mg fertilizers (Ca-Mg lime) did not produce reactions until three years after the application. In the Ardennes, in a 40 yr old spruce stand suffering from severe Mg deficiency, a Ca and Ca-phosphate fertilization applied 5 yr before yellowing appeared had positive effects on crown density, discoloration and wood production. Conversely, a single N fertilization in this experiment, as well as in a young plantation in the Vosges, had a marked negative effect on Mg nutrition, even at low levels.     

Fertilization of declining conifer stands in the Vosges and in the French Ardennes

Twenty fertilization experiments were set up in 1985 and 1986 in the Vosges mountains, using mostly calcareous or Mg fertilizers, in order to verify whether fertilization can attenuate defoliation and yellowing recently recorded in Silver fir and Norway spruce. In the Ardennes, a fertilization experiment set up in Norway spruce stands prior to the appearance of yellowing was assessed. In these areas, the total acid deposition is about 2 kg eq H⁺ ha⁻¹ yr⁻¹. Nitrogen deposition is much more important in the Ardennes (52 kg N ha⁻¹ yr⁻¹ in form of wet and dry deposition) than in the Vosges (16 kg N ha⁻¹ yr⁻¹). The results in the eight adult stands showed no uniform reaction to the treatments. Spontaneous improvement, further deterioration independently of the treatment, as well as a positive reaction to fertilization were observed. Additional N or P fertilization sometimes had a beneficial effect on Ca or Mg treatments. The selection of the stands with the best response turns out to be difficult, as the nutrient contents of needles alone seem not to be a satisfactory criterion for selection. Young plantations reacted positivley to the treatments. Soluble Mg fertilizer leads to an immediate response. Low solubility Ca-Mg fertilizers (Ca-Mg lime) did not produce reactions until three years after the application. In the Ardennes, in a 40 yr old spruce stand suffering from severe Mg deficiency, a Ca and Ca-phosphate fertilization applied 5 yr before yellowing appeared had positive effects on crown density, discoloration and wood production. Conversely, a single N fertilization in this experiment, as well as in a young plantation in the Vosges, had a marked negative effect on Mg nutrition, even at low levels.     

水稻栽后植株氮素积累特征及其与根系生长的关系

以冈优22、Ⅱ优162和K优047为材料,通过大田试验研究了不同种植方式下水稻秧苗栽后根系和地上部氮素积累的动态特征及其与根重的关系。结果表明,栽后40.d内,地上部及根系氮素积累量呈指数模型增加。茎鞘、发根节和叶片氮含量与根重呈极显著正相关;根系氮含量与根重呈显著负相关;各器官氮积累动态与根重均呈极显著的正相关关系。全生育期植株氮积累量拟合Logistic曲线较好,决定系数在0.988以上,氮素积累量与根重呈显著的正相关关系,生育期越靠前,相关系数值越大。3种种植方式中,自移栽至孕穗期氮积累量以常耕插秧最高,常耕抛秧其次,免耕高留茬抛秧较低;孕穗后免耕高留茬抛秧各器官氮含量最高,氮积累量也逐渐超过常耕抛秧。3个杂交稻组合中,前期以冈优22的氮积累量最高,后期Ⅱ优162增加速率较快,K优047在整个生育期中均最低。     

Soil acidification by atmospheric pollution and forest growth

In recent years concern has been expressed about the danger of harmful pollution deposits which affect areas at great distances from the emission sources. The investigation was so designed that a possible reaction in growth resulting from a supposed acidification could be observed as far as possible. A poorer growth development was observed in regions, which are suspected of being more susceptible to acidification than those regions which are presumed to be less susceptible in this respect. We have found no good reason for attributing the reduction in growth to any cause other than acidification.     

Soil organic carbon and its sorptive preservation in central Germany

Soils are increasingly viewed as a potential sink for atmospheric carbon. However, their use to meet CO₂ emission reductions is problematic for there are knowledge gaps regarding the mechanisms involved in the sequestration of organic carbon (OC). There is evidence which suggests that OC concentrations are controlled by the mineralogy and related specific surface area (SSA) of a given soil. The goal of this study was to examine the importance of sorptive mechanisms on OC stabilization. The objectives were (i) to determine the SSA, clay mineralogy and dithionite‐ and oxalate‐extractable Fe and Al concentrations of several soils, and (ii) to analyse how these variables are related to OC concentrations. Five soils were sampled and analysed: two Umbrisols, a Stagnic Acrisol, an Anthrosol/Vertisol/Gleysol‐Chernozem and a Gleysol (FAO terminology), all located in Hesse, Germany. Oxalate‐extractable Fe and Al were found to be the best predictors of OC concentrations in the soils examined. Specific surface area correlated significantly with the OC content of the B and C horizons of one Umbrisol and the entire profile of the Anthrosol/Vertisol/Gleysol‐Chernozem. The relationship between SSA and OC concentrations is likely to be restricted to certain soils and might be a product of the sorptive capacity of Fe and Al oxides. We can assume that the available mineral surface area on oxides is a limiting factor in terms of a soil's capacity to sequester organic carbon. As such, attention should be paid to soil mineralogy and how this might limit the use of soils as a sink for atmospheric CO₂.     

Mineral element composition of declining and healthy stands of red spruce in western Massachusetts

Abstract

Concentrations of N, P, K, Ca, Mg, and Mn were determined in one‐, two‐, and five‐year‐old needles from upper and lower crowns of declining and healthy red spruce (Picea rubens Sarg.) to assess nutritional deficiencies as causes of severe defoliation in upper‐elevation forests in western Massachusetts. Concentrations of N and K did not differ between stands or positions in crowns but decreased with leaf age. In declining stands, mean Ca concentrations were the same in the upper and lower crowns (3.2 mg g^‐1), whereas in healthy stands, Ca was higher in the lower crown (4.8 mg g^‐1) than in the upper crown (3.9 mg g^‐1). Five‐year‐old needles of healthy trees had higher Ca than those of declining trees (6.0 and 3.8 mg g^‐1, respectively). Mean concentrations of P and Mg in declining trees were 0.9 and 0.5 mg g^‐1, respectively, with each element being at threshold levels of sufficiency. Mean concentrations of P and Mg, respectively, were 0.3 mg g^‐1 and 0.2 mg g^‐1 lower in needles of declining trees than in healthy trees. Five‐year‐old needles of declining trees were lower in P and Mg than those from healthy trees. Mean Mn concentrations were lower in needles of declining trees than in healthy trees (0.4 vs 1.3 mg g^‐1). The results suggest that low P, Mg, and possibly Ca concentrations in needles of declining trees may contribute to the decline.     

红壤丘陵区不同植被类型土壤颗粒分形与水分物理特征

为探明红壤丘陵区不同植被对土壤分形结构及水分物理特征的改良作用与机制,运用土壤分形学和水文物理学原理与方法,以南方红壤丘陵区福建省长汀县为例,研究经济林、针阔混交林、乔灌混交林及针叶林4种植被类型土壤颗粒组成、分形维数、水分物理参数及其相关性。结果表明:1)红壤丘陵区不同植被类型土壤中以粗砂粒质量含量最高,细砂粒和石砾质量含量次之,粉黏粒质量含量较低,与裸地相比,不同植被类型具有显著提高土壤细砂砾和粉黏粒质量含量的作用,并且混交林作用程度高于纯林;2)红壤丘陵区不同植被类型具有降低土壤密度、增加土壤孔隙度的功能,针阔混交林、乔灌混交林、针叶林、经济林土壤的饱和蓄水量分别是裸地的1.20、1.16、1.14和1.10倍,表土层(0～20 cm)贮水能力好于表下土层(20～40 cm);3)土壤颗粒分形维数与土壤粉黏粒、总孔隙度、饱和蓄水量、孔隙比呈极显著正相关,与石砾质量含量、土壤密度呈极显著负相关,红壤丘陵区4种植被类型土壤均为不均匀性良好的土壤,以混交林土壤粒径分布结构较好,尤其是以针阔混交林的最好,其次是纯林的,针叶林好于经济林,表土层(0～20 cm)大于20～40 cm土层。     

Liming and fertilization as mitigation tools in declining forest ecosystems

In central Europe the ‘new type’ forest damages have been observed since the mid 1970's. Various investigations indicate that the declines are frequently associated with nutritional disturbances. Good correlations between the site specific substrate chemistry and the actual nutritional status of the trees/stands were found. To explain the sudden and widespread appearance of the forest declines, adverse anthropogenic impacts mainly due to elevated emissions of air pollutants and their atmospheric derivatives are hypothesized in combination with natural stress factors. Causal mechanisms include soil degradation due to accelerated soil acidification and increased nutrient leaching from the canopy of forest stands. Fertilization and liming experiments have demonstrated that a fast and sustained revitalization and restabilization of declining forest ecosystems marked by nutritional disturbances can be achieved. This is demonstrated by chemical and histological foliar analyses generally combined with a visible improvement of the phenotype. Soil analyses reveal a considerable positive change of the chemical soil status due to the site and species specific application of appropriate amounts of fast soluble fertilizers and lime. Considering these recent favorable findings, as well as based on observations from historic fertilization and liming trials nutrient supplementation and liming have become common tools to counteract the new type forest damages in West Germany.     

土壤酸度的调节对烤烟根系生长与烟叶化学成分含量的影响

采用盆栽试验研究实施石灰调节土壤酸度对烤烟生长和烟叶化学成分含量影响的结果表明，土壤pH值从5.0调节至5.5-6.6，能明显促进根系生长和烤烟对N、P、K元素的吸收，提高N、P、K肥料利用率，土壤pH值调节在7.0以上，根系生长受抑制。随土壤pH值增加，烟碱、总N、Ca含量增加，总糖、Mg、Mn、Zn、Cu和B含量下降，K含量变化不大。土壤pH值调节至5.6-6.6，烤后烟叶各化学成分含量较适中，品质较好。酸性土壤施石灰要注意配施适量的Mg肥和微肥。     

Soil monitoring in Germany

Background Aim and Scope

Soil monitoring in Germany should register the current soil condition, monitor its changes and provide a forecast for future development. In order to achieve these goals, the long-term soil monitoring sites in Germany (BDF -Bodendauerbeobachtungsflächen) have been established by the federal states. This has been done according to criteria worked out by soil monitoring experts. In this article a method for the examination of the suitability of Germany’s soil monitoring sites for soil conservation and protection purposes, as well as for environmental monitoring and reporting, is introduced. This method includes the landscape representativity of soil monitoring sites as well as the comparability and spatial validity of collected data.

Methods

BDF-criteria are operationalized in a three-step procedure: At first, a metadatabase is established containing information that allows the comparison of monitoring sites by means of measuring parameters, methods and quality assurance as well as quality control of measurements. Secondly, the representativity of the BDF-sites for soil types, land use, vegetation, and climate (air temperature, duration of sunlight, precipitation) by means of frequency statistics and neighborhood analysis is quantified. At last, the spatial validity of soil monitoring data is examined through the application of geostatistical methods. Both data and statistical methods are integrated in a Geoinformationsystem (GIS).

Results

The analysis of metadata reveals that the soil monitoring is of great importance for environmental analysis because of its ecosystematic concept and its considerable degree of methodical harmonization. Assuming that the number of BDF should be directly proportional to the areal portion of an ecoregion in the entire area of Germany, it can be shown that the geographical distribution of BDF-sites fit quite well according to the areal portions of the ecoregions. The maximum deviation is about ñ 6%. If the number of BDF is not proportional to the area covered by a certain combination of site characteristics, these areas can either be complemented or thinned through MNR-indices derived by neighborhood analysis. Soil monitoring sites can be added where the MNR are highest and removed where MNR are lowest. Throughout the neighborhood analysis, three GISmaps were processed: ecoregionaiization, soil types and land use. Decisions to reduce the spatial density of monitoring sites should not only be based on the landscape representativness of monitoring networks, but on the support of geostatistical analysis of measured data as well. For example, the results of the geostatistical analysis of Pb-concentrations in top soils are compared for a complete and a reduced BDF monitoring network.

Conclusion

The investigations show that not only the proportional distribution of monitoring sites in landscape units (landscape representativity) is important for the assessment of environmental monitoring networks; The number of monitoring sites, rather, should be sufficient to guarantee a spatial representation of the respective measurement variable. Their geographical distribution should be based on the spatial model of landscape units. Additionally, particular criteria that are important for the object of investigation, for example the distance to emitters, should also be considered.

Perspective

It is strongly recommended that activities for the integration of ecological data collected in diverse monitoring networks be intensified. A central German environmental information system should be established in order to realize integrated analysis of environmental data by aspects of harmonization and representativity. Furthermore, Internet and GIS technologies should be used to assist the environmental data acquisition in Germany. A prototype of such an instrument, the socalled Internet and GIS-based Environmental Monitoring System (IGUS) was already established and tested in the moss monitoring program 2000.

     

Soil carbon and nitrogen budget in Scots pine (Pinus sylvestris L.) stands along an air pollution gradient in eastern Germany

Litterfall, bio- and necromass of the forest floor vegetation, decomposition of recent organic material, soil respiration and humus stocks were examined in 3 Scots pine stands along an air pollution gradient in eastern Germany. High nitrogen loads and increased pH values due to Ca deposition caused shifts in the vegetation structure, and higher biomass production of the forest floor vegetation, whereas needle litter production was not impacted. Simultaneously, decomposition rates of the recently harvested forest floor vegetation decreased with increasing pollutant loads, but needle litter and soil organic matter decomposition rates did not differ between the sites. Consequently, soil carbon and nitrogen stocks increased with increasing pollutant input.     

Soil acidity factors and growth of white clover (Trifolium repens L.) in acid hill soils

Abstract. Correlation analysis was used to determine the main factors related to soil pH and to yield of white clover in a range of hill soils. Results for 109 Northern Ireland pasture soils showed that pH (H₂O) was significantly correlated with exchangeable Ca, total exchangeable bases, base saturation, P, exchangeable Al and Al saturation, but not with exchangeable Mn. Clover yield (dry weight of shoots) in 12 acid soils from Northern Ireland, Scotland and the Falkland Islands was significantly correlated with exchangeable Ca, total exchangeable bases and Al saturation. The results support the use of Al saturation rather than exchangeable Al, soil solution Al or pH when calculating lime requirements to overcome these limiting factors in hill soils.     

Effects of air pollutants on mineral nutrition of Norway spruce and revitalization of declining stands in Austria

The vigor of Norway spruce stands in the Bohemian Forest of Austria was correlated with site factors, informations on historic land use, and chemical properties of the soils and spruce needles. The study confirmed that trees on west exposed slopes and plateaus in higher elevation have lower crown densities. The soils in the area are generally low in base saturation. Historical land use, such as litter raking, grazing and burning of biomass for potash led to nutrient depletion. Increasing deposition of atmospheric N during the last decades alleviated N stress, but increased Ca and Mg stress. N∶Mg ratios in needles of declining stands are wide, indicating N induced nutritional imbalances. PH values in the mineral topsoil are very low on W-slopes and plateaus. Measurements of pollutant deposition at three different sites indicate a strong influence of aspect and elevation on input rates. In a southwest exposed stand and a stand on a hilltop, facing the prevailing winds, substantially more S and N was recovered in the throughfall than in northeast exposed stand. Deposition rates in the open did not differ significantly. High NO₃ ^? concentrations in the soil solution of the southwest exposed site indicate N saturation of the system. In order to test the hypothesis that mineral deficiency and nutritional disorders contribute to the poor vigor of these stands, fertilizer experiments were established. Fertilization with a combination of an organic fertilizer (BACTOSOL^**)) and a magnesite fertilizer (BIOMAG^*)) significantly improved crown density, growth, seed viability, and mineral nutrition as inferred from foliar analysis. NO₃ ^? leaching in the combined BACTOSOL+BIOMAG treatment increased during the first and second growing season after fertilization but leveled off to values typical for the control plots after three years. Mg content of the soil solution increased both in the BIOMAG and the combined BACTOSOL+BIOMAG treatment. These experiments show that the nutritional status and the resilience of declining forests in the Bohemian Forests of Austria can be easily improved by proper fertilizer treatment.     

Soil sterilization effects on root growth and formation of rhizosheaths in wheat seedlings

Sterilized soils are frequently used in experiments related to soil biology. Soil sterilization is known to alter physicochemical characteristics of soil, plant growth and community structure of the newly developed bacterial population. However, little information exists regarding soil sterilization effects on belowground processes mediated through root–microbe–soil interactions, e.g., development of rhizosheaths which significantly promote the plant growth under stress environments. The present study was conducted to elucidate effects of soil sterilization on wheat root growth and formation of rhizosheaths in relation to chemical changes caused by soil sterilization and the proportion of expolysaccharide (EPS)-producers in bacterial population recolonizing the sterilized soils. Wheat plants were grown for two weeks under greenhouse conditions either in the unsterilized soil or in soils sterilized by autoclaving (121 °C, 1 h) or by gamma (γ)-irradiation (50 kGy). While soil sterilization had no effect on the release of macronutrients, both sterilization procedures significantly increased the electrical conductivity, water-soluble carbon and DTPA-extractable Mn. Seedlings grown in sterilized soils produced higher root biomass and the rhizosheath soil (RS) mass as compared to those grown in the unsterilized soil. Soil sterilization also increased the root length, surface area, volume and number of tips. In bulk soil, RS and on roots, the proportion of EPS-producers in the total bacterial population was higher in sterilized treatments than in the unsterilized. Amending the unsterilized soil with glucose-C increased the root biomass, whereas adding Mn II increased the RS mass. The results showed that soil sterilization by autoclaving or γ-irradiation increases the root growth and RS mass of wheat seedlings. The water-soluble C and DTPA-extractable Mn released upon sterilization, and the increased proportion of EPS-producers in the bacterial population recolonizing the sterilized soils were involved in the observed effects. The results may have implications in studies using autoclaved or γ-irradiated soils to investigate soil–plant–microbe interactions and signify the need to account for intrinsic stimulatory effects of soil sterilization.     

土壤微生物生物氮与植物氮吸收的关系

The contents of the soil microbial biomass nitrogen (SMBN) in the soils sampled from the Loess Plateau of China were determined using chloroform fumigation aerobic incubation method (CFAIM),chloroform fumigation anaerobic incubation method (CFANIM) and chloroform fumigation-extraction method (CFEM). The N taken up by ryegrass on the soils was determined after a galsshouse pot experiment. The flushes of nitrogen (FN) of the soils obtained by the CFAIM and CFANIM were higher than that by the CFEM, and there were significantly positive correlations between the FN obtained by the 3 methods. The N extracted from the fumigated soils by the CFAIM,CFANIM and CFEM were significantly positively correlated with the N uptake by ryegrass. The FN obtained by the 3 methods was also closely positively correlated with the N uptake by ryegrass. The FN obtained by the 3 methods was also closely positively correlated with the plant N uptake. The contributions of the SMBN and mineral N and mineralized N during the incubation period to plant N uptake were evaluated with the multiple regression method. The results showed that the N contained in the soil microbial biomass might play a noticeable role in the N supply of the soils to the plant.