Soil organic matter quality and microbial activities in spruce swamp forests affected by drainage and water regime restoration

The effect of spruce swamp forest (SSF) drainage and water regime restoration on soil organic matter (SOM) quality and soil microbial heterotrophic activities was studied in pristine, drained and restored SSF in the Bohemian Forest, Czech Republic. Sequential chemical SOM fractionation using cold and hot water and hot acid was used to separate SOM fractions according to their mobility and potential lability/recalcitrance, and Fourier transform infrared spectra were used for SOM characterization. Soil physicochemical parameters and heterotrophic microbial activities were also determined. Drainage of SSF had significant long‐term effects (more than 50 yr) on plant communities and SOM quality. On drained sites, cover of sphagnum moss and sedge was much smaller than on pristine locations. A greater proportion of recalcitrant compounds and a smaller proportion of labile compounds were found in drained SSF as compared to pristine sites, which first led to an energy limitation and was followed by a decrease in microbial biomass and heterotrophic microbial activities (CO₂ production, methanogenesis and methanotrophy). Restoration resulted in slow progressive changes in the vegetation cover, including the spread of sphagnum mosses, retreat of mosses typical of drier conditions and increased sedge cover compared with drained SSF. Moreover, soil physicochemical parameters (pH and bulk density), hot‐water‐extractable C and methanotrophic activity tended to evolve towards the pristine SSF and seem to be good indicators of the restoration process. No other SOM fractions changed significantly after restoration. Thus, to change significantly overall SOM quality and most microbial heterotrophic activities following restoration, more than 7 yr are required.     

Soil enzyme activity changes in different-aged spruce forests of the eastern Qinghai-Tibetan plateau

Activities of selected soil enzymes (invertase, acid phosphatase, proteinase, catalase, peroxidase and polyphenoloxidase) were determined under different spruce forests with restoration histories of 5, 13, 18, 23, 27 years and an old growth forest over 400 years old in the eastern Qinghai-Tibetan Plateau, China, and their possible use as indicators of ecosystems health were analyzed. Plots 10 × 10 m with 4 replications were established to investigate three hypotheses: soil enzyme activities a) would increase with the restoration process; b) would be greater in surface soils than at lower depths; and c) would be correlated to selected physicochemical properties. Results showed that as the forests developed after restoration, invertase and peroxidase activities usually increased up to the 23 year point. Also soil enzyme activities were associated with surface soils and decreased with depths, suggesting that in earlier restoration stages surface addition of organic fertilizer to soils might be more effective than additions at depth. In the 0-20 cm soil, there were significant correlations (P < 0.01 or < 0.05) between some soil enzyme activities and some selected chemical properties. Therefore, temporal changes in enzyme activities should be included as an indicator when evaluating sustainable forest management practices.     

Microhabitats of Collembola (Insecta: Entognatha) in beech and spruce forests and their influence on biodiversity

Collembolan communities were studied in 41 microhabitats in beech and spruce forests of south ( ofín and umava) and central (Jevany) Bohemia. The communities of Collembola were analysed using TWINSPAN and CANOCO programs. The aim of this study was to establish differences between patch (microhatitat) communities and the main forest community in spruce and beech forests, the differences between both types of forests and among different regions of Bohemia. Further questions were: is there a difference in microhabitat communities during secondary forest succession? do some species live exclusively in one or few microhabitats? and does microhabitat diversity influence the biodiversity in forest soils? Material comprising  25 590 specimens of Collembola belonging to 142 species was analysed. Highly significant differences were determined between microhabitat communities in beech and spruce forests, as well as among forests in different regions of Bohemia. Significant differences were also found among microhabitats in forests of different ages. Also, some microhabitat communities of Collembola, e.g. moss on boulders, were significantly different from their main forest community. Certain collembolan species existed exclusively in one or two microhabitats. Patches therefore influenced substantially biodiversity in these forest soils.     

A comparison of methods used for determination of cation exchange capacity

Abstract

Cation exchange capacity of ten non‐calcareous and non‐saline soils from Queensland, Australia, has been determined by the ammonium acetate method using different procedures, by an ammonium chloride method at pH8.5, and by three methods which attempt to approximate field conditions. Procedural differences in the ammonium acetate method produced variation in results, and methods using approximate field conditions gave much lower values for those soils considered to have variable charge properties.     

样点代表性等级采样法在丘陵山区土壤表层有机质制图中的应用

基于样点代表性等级的土壤采样方法在成本、应用性、制图准确度上具有明显的优势,但在其他方面(如敏感性)上仍需要大量研究。为了进一步研究这种方法的可用性,本文以安徽宣城境内的丘陵山区为研究区,应用该方法分析以往土壤采样点的代表性等级,进而研究样点代表性等级对土壤制图准确度的影响。研究结果表明:①高等级代表性链广泛存在,而低等级代表性链则较少;②代表性链的等级有效地从不同程度反映出土壤形成环境的变异;③样点代表性采样设计的采样点与规则化网格采样、目的性采样有很大不同;④一般地,随着低等级样点的逐渐加入,制图准确度增加,但增幅随着样点等级的降低而降低。这些结果说明,样点代表性等级采样法在应用、成本、准确度几个方面都有明显的优点,因而具有较好的应用前景。需要注意的是,在应用该方法选择样点时,样点的代表性应达到一定级别,以避免制图准确度不会因为样点的加入而降低。此外,由于其他地形地貌类型(如平原区)还缺乏较好的土壤协同环境因子,该方法的应用受到了一定程度的限制。     

Influence of local illumination and plant composition on the spatial and seasonal distribution of litter-dwelling arthropods in a tropical rainforest

Using pitfall traps, we evaluated the spatial and seasonal variance in arthropod abundance, species richness, higher taxonomic and species composition, and guild structure within the ground litter of seven sites in a relatively undisturbed rainforest in Panama. We examined each of these five arthropod-dependent variables at two spatial scales (a few meters and a few hundred meters) and one temporal scale (a few months encompassing dry and wet periods), against environmental variables including local illumination and plant composition. Trap catches (9458 arthropods collected during 630 trap-days) were high compared to similar studies in temperate forests. We observed spatial and seasonal differences in abundance, species richness and composition of litter-dwelling arthropods. Often these differences appeared weakly related to geographical coordinates. They reflected forest structure (basal area) and local plant composition, and less so illumination patterns or seasonal changes in radiation. Seasonal variance was high and may relate to surrogate variables accounting for seasonal changes in litter moisture. The composition of higher taxa and species was often predicted by different independent variables at the three scales studied. Guild structure was difficult to predict. Our study lead us to expect that litter-dwelling arthropods may be more seasonal than soil microarthropods in tropical rainforests; and that tropical litter-dwelling arthropods may also be more spatially variable and seasonal than their temperate counterparts. We also recommend that conservation studies using pitfall traps in tropical rainforests should focus on: (1) taxonomic resolution to understand the functional complexity of soil organisms; (2) spatial replication to address subtle changes in plant composition throughout the study area; and (3) seasonal replicates to be commensurate with seasonal changes in litter moisture.     

Changes in humus properties and collembolan communities following the replanting of beech forests with spruce

Differences of collembolan communities within the organo-mineral A layer were studied in relation to physico-chemical changes in humus at nine sites of beech forests (Fagus sylvatica L.) and first generation spruce stands (Picea abies (L.) Karst.), planted on former beech forest 30 years ago (Central Pyrenees, France). Changes in humus form were caused by the spruce plantation and occurred mainly within the fermentation horizon where acidifying litter accumulation increased the horizon depth. The recent replacement of beech by spruce induced a shift from mull towards moder humus forms, which is explained by the decreasing organic matter turnover rate. A significant decrease in the three exchangeable cations and pH under spruce was also observed. Collembolan species diversity within the A horizon was significantly lower under spruce at this early stage of the silvogenetic cycle. Differences between species composition of Collembola between the two forest stands is related to changes in environmental conditions (e.g. nutrient availability, soil porosity, soil moisture). This study shows how forest management practices are susceptible to modify biological activity within the A horizon under exotic conifer plantations.     

Bioactivity in limed soil of a spruce forest

Summary The stimulative effect of lime on the bioactivity of various soil horizons was demonstrated by the ATP test, and respiration and microcalorimetric measurements, but not by FDA hydrolysis or the iron reduction test. The latter showed clear inhibition. When the natural structure of layers was saved while sampling, a smaller stimulation of bioactivity was observed than in the case of mixing natural layers. No stimulation was recorded when the lime layer was removed.     

黄土残塬沟壑区利用阔叶树种枯落叶对针叶林土壤极化的防治效应

人工纯林的长期连续生长或连栽所引起的土壤极化是导致土壤退化和影响人工林生态系统稳定及可持续发展的重要原因,防治的根本途径是引入其他树种形成针阔混交林或者利用其他树种枯落叶进行根系附近的局部客置。针对在黄土残塬沟壑区的针叶纯林,通过野外采集典型林地腐殖质层土壤和不同森林和城市道路绿化阔叶树种当年枯落叶后进行室内混合培养试验,研究表明:(1)油松枯落叶会引起土壤有机质、有效磷含量、微生物数量增加和脱氢酶、磷酸酶、多酚氧化酶等多种酶活性增强的正向极化,但同时却会引起土壤碱解氮含量和脲酶、蔗糖酶活性降低的负向极化。与小叶杨和沙棘混交或将其枯落叶客置可以明显改善油松林地土壤性质,而柠条、刺槐和辽东栎则反会恶化土壤性质。客置七叶树、紫叶李、泡桐枯落叶可以明显改善油松林地土壤性质,其次为银杏,而其他树种均不适宜。(2)侧柏枯落叶会引起土壤有效磷、速效钾含量、微生物数量增加和蔗糖酶、脱氢酶、磷酸酶、蛋白酶、多酚氧化酶活性增强的正向极化,但同时却会引起土壤碱解氮含量和脲酶活性降低的负向极化。与辽东栎、刺槐混交或将其枯落叶客置可以明显改善侧柏林地土壤性质,其次是沙棘和柠条,而小叶杨则反会恶化土壤性质。客置玉兰、七叶树、法桐枯落叶可以明显改善侧柏林地土壤性质,其次为杜仲、五角枫,而其他树种均不适宜。该研究结果将对于大面积人工纯林改造、混交林营建等方面具有重要的理论指导和实践意义。     

Comparison of Soil Sampling Devices for Soil Bulk Density Determination for Carbon Sequestration Monitoring

Soil bulk density is often used to adjust soil carbon (C) values for changes in soil density because of management differences in C-sequestration studies. Often hand-sampling devices used for soil fertility monitoring may be used for sampling soil to a depth of up to 30 cm. Four sampling devices of differing characteristics that can be used with hand-sampling equipment across full tillage, reduced tillage, and no-tillage to determine soil bulk density were evaluated. There were no significant differences in soil bulk density values between three cylindrical devices, which measured from 19 to 31 mm in diameter. However, a 21 mm × 76 mm rectangular device gave significantly lower bulk density values than the cylindrical devices. Calculation of soil organic carbon (SOC) mass per unit area showed similar results for the cylindrical devices with the rectangular device giving a significantly lower value than the cylindrical devices. Using a cylindrical device on a hand probe in a consistent manner will give satisfactory results when sampling surface soils.     

Soil respiration in eucalypt forests of southeastern Australia

Summary Soil respiration was measured in five eucalypt forests of southeastern Australia. Regardless of the type of forest, the rate of respiration in soils responded to the addition of an available C source (glucose) and did not to the addition of N or P. Addition of glucose, at up to 100% of the glucose equivalent in soil, increased the rate of respiration sigmoidally. The concentration of glucose needed to achieve the maximum rate of respiration in the topsoil (0–2 cm) of an Eucalyptus regnans forest was at least an order of magnitude greater than its equivalent in the soil. The results indicate that microbial respiration in soils from eucalypt forests is limited by an available source of C.     

Soil ciliates (Protozoa: Ciliophora) from evergreen rain forests of Australia, South America and Costa Rica: diversity and description of new species

This paper provides, for the first time, comprehensive data on alpha diversity of soil ciliates from evergreen tropical and temperate rain forests. Thirty-three samples were collected in Australia, Tasmania, Amazonia and Costa Rica and analysed with the non-flooded Petri dish method, which reactivates the ciliates’ resting cysts from air-dried samples. The 175 taxa found contained 34 new species, 4 of which are described in this paper, viz. Platyophrya paoletti n. sp., Lamtostyla abdita n. sp., L. granulifera n. sp., and Apoamphisiella tihanyiensis (Gellért and Tamás 1958) n. gen., n. comb. Although this is a considerable number, it is much lower than one would expect. The data would be even more perplexing if the four rich samples (up to 90 species/sample) from the Manaus floodplain were excluded. We then would be confronted with about 90 taxa in 29 samples, of which 13 contained fewer than ten species. A hypothesis is put forward that the non-flooded Petri dish method is inappropriate for studying soil ciliate diversity in evergreen rain forests because most species have a reduced capacity to produce dry-resistant (protective) resting cysts due to the permanent wetness of their habitats. This view is supported by a comparative analysis of a fresh (containing 40 species) and air-dried/rewetted (2 species only) sample from a cloud rain forest near Merida (Venezuela), and the observation that the capacity of soil ciliates to produce resting cysts often dramatically decreases after prolonged laboratory cultivation in liquid media. Direct microscopy of fresh samples seems to be an appropriate alternative because specimens can be easily collected due to their considerable abundance (≥1000 individuals/g wet mass of litter). Received: 8 April 1997     

土壤制图中多等级代表性采样与分层随机采样的对比研究

采样设计是土壤地理研究中备受关注的重要问题。本文以区域尺度土壤属性制图为例,将多等级代表性采样与经典采样中的分层随机采样进行对比研究。以安徽宣城研究区的表层砂粒含量为目标要素,采集数量均为59个的两套样点,设计不同数量(46、58和59)的样点分组,采用两种制图方法进行制图并利用独立验证点进行评价。结果表明:1)无论是采用多元线性回归方法还是基于环境相似度的制图方法,在同等样点数量下,利用代表性样点所得土壤图精度均高于利用随机样点所得精度,并且利用少量代表性样点(46个)所得土壤图精度也高于利用多量随机样点(59个)所得精度;2)随着代表性较低样点的增加,土壤制图精度基本有一个提高的趋势,而采用随机样点所得土壤图的精度波动较大。因此,可认为多等级代表性采样方法是一种可用于区域尺度土壤调查的有效采样方法,且比分层随机采样高效、稳定。     

The influence of bark beetles outbreak vs. salvage logging on ground layer vegetation in Central European mountain spruce forests

Changes in the herb and moss layers of mountain spruce (Picea abies (L.) Karst.) forests after bark beetle (Ips typographus (L.)) outbreak were compared with and without forestry intervention. The study area is situated in the Šumava National Park (Czech Republic, Central Europe), where an extensive bark beetle outbreak occurred in the 1990s. Parts of forests were left without interventions, while salvage logging was applied in other areas. Altogether, 18 permanent research plots were established in: (1) climax stands with completely dead canopy, (2) climax stands where salvage logging was applied (clearcuts), and (3) waterlogged stands with only partly dead canopy. Vegetation composition of the ground layer and species numbers were evaluated in 1997 and 2002.The effect of salvage logging on vegetation was greater than that of the bark beetle outbreak itself. Forest herb species and partly also bryophytes survived relatively well under untouched dead canopy. The fewest changes occurred under the partly dead canopy in waterlogged forests. The herb layer expanded in clearcuts originated due to salvage logging, being dominated by grasses. Bryophytes were more susceptible to logging than herbs; their cover in clearcuts was markedly lower and composition changed towards pioneer species. The results show that a natural succession of mountain spruce forests after a bark beetle outbreak, if left without interventions, will probably avoid a pioneer stage and direct recovery of the forests will be possible. Salvage logging had negative effects on species composition of the spruce forests, delayed the forest recovery, and should not be permitted in the national park.     

Effect of artificial irrigation,acid precipitation and liming on the microbial activity in soil of a spruce forest

Summary The effects of irrigation, acid precipitation and liming on the bioactivity in a spruce forest soil were measured with different tests. Except for the iron reduction test and the FDA hydrolysis, the highest activities were measured in the upper horizons and mostly decreased gradually in the deeper ones. The determination of heat output and respiration without additional energy supply and ATP measurement gave similar results: acid precipitation inhibits the bioactivity in O₁ and O_f1, layers; lime stimulated it mostly in O_f2 horizons. Except for the results of ATP measurement, in O_f2 horizons the influence of lime exceeded that of acid irrigation. The results obtained from respiration and microcalorimetric measurements after the introduction of an energy supply were similar: Humidity, derived either from acid precipitation or from irrigation, stimulated the activity as well as lime, clearly in O_f2, to a smaller extent also in deeper horizons. The bioactivity in Oft increased significantly in the plots in the order: control, plot with acid irrigation, plot with normal irrigation, limed plot, limed plot with acid irrigation, and limed plot with normal irrigation. The difference between irrigated and acid-irrigated plots is due to the inhibitive effects of protons and SO ₄ ^2– . The FDA hydrolysis test showed a clear stimulative effect of humidity in O_f horizons of non-limed plots. With the iron reduction test, stimulation in acid-irrigated and inhibition in limed samples was demonstrated. The maximum bioactivity measured with this method was localized in deeper horizons.     

The impact of clearcutting and partial harvesting systems on population dynamics of soil nematodes in coastal Douglas-fir forests

Soil nematodes were used as bioindicators to compare possible differences in soil ecological conditions in Douglas-fir forests harvested by clearcutting and by two partialharvesting systems, namely shelterwood and extended rotation. An unlogged forest block was used as a control treatment. The pre- and post-harvest comparisons were based on total abundance of the nematodes, their trophic structure, and relative abundance of the nematode taxa found in the four blocks. The nematode and soil data were obtained bimonthly over a year. Pre-harvest nematode abundance and taxonomic composition were similar at the four blocks. Post-harvest data were obtained 6-7 months after the harvesting treatments were instituted. The post-harvest abundance at the three logged blocks was reduced to varying levels as compared to the control block, and analysis of variance showed that the severity of impact of the harvesting treatments on nematode abundance ranked as: clearcut shelterwood > extended rotation unlogged control. However, the taxonomic and trophic structures of the nematode community, which consisted of 48 taxa in these forests, were only slightly altered by any of the harvesting treatments as shown by maturity and diversity indices and by multivariate analysis.     

不同培肥方式对西藏中部退化土壤微生物的影响研究

试验研究不同培肥方式对西藏自治区中部退化土壤微生物的影响结果表明 ,施用有机肥 ,特别是化肥与有机肥配施对土壤微生物和动物 (蚯蚓 )有重要影响 ;土壤pH值为 5 .91～ 6 .0 2内土壤细菌与有机质含量呈显著正相关 ,并在土壤微生物数量构成中占绝对优势 ,对作物N、P营养有较大贡献 ,土壤真菌亦呈此趋势 ;土壤放线菌则与土壤有机质、速效氮、速效磷含量呈负相关。     

The effect of lime on microbial activity in spruce (Picea abies L.) forests

Summary The use of lime increased heat output and decreased the C:N ratio (global indicators of biological activity) in the organic horizons of a spruce forest (Picea abies L.) soil. These changes were still present after 18 years. During the same period, the muramic acid content increased slightly, while the concentration of both ergosterol and glucosamine decreases. The ratios of ergosterol or glucosamine to muramic acid decreased significantly after 3 years in the plots that had been irrigated and limed, and after 8 years in the limed non-irrigated plots.