The role of soils in the regional carbon budget of pine forests in Karelia

The carbon pool and its fluxes were studied in Karelian pine forests of automorphic sites for the characterization of the regional carbon cycle. On the permanent sample plots arranged in pine stands (dominant forest types) of the middle and northern taiga, the structure and dynamics of the phytomass, as well as the composition of the soil organic matter, were investigated. The contribution of different components of the forest ecosystems to the regional carbon budget was studied. The carbon pools in the soils of the middle and northern taiga subzones were 330–440 × 10² and 440–550 × 10² kg/ha, respectively. The share of soil carbon in the total carbon pool of the forest biogeocenoses studied amounted to 46–35 and 33–24%, respectively. The period of considerable carbon fixation in the pine ecosystem (nearly 20 × 10² kg/ha/yr) turned out to be limited to the middle-aged stands. In the mature and overmature pine forests, only 4 × 10² kg of C/ha/yr were fixed. The main part of carbon in the soil (65–75%) was contained in the illuvial horizons, although its content there was less that 1% as compared to 30–50% in the forest litters. On industrial harvesting of wood, the main reserves of soil carbon are not spent; only the fund of mobile carbon in organic horizons of poor soils is exhausted or carbon accumulates intensely due to the development of continuous plant cover on fertile soils.     

The Influence of Vegetation on the Forest Soil Properties in the Republic of Karelia

Eurasian Soil Science - The effect of vegetation on soil properties (acidity, C/N ratio, content of exchangeable nutrients) was assessed for the northern and middle taiga forests in the Republic of...     

Soils of Low-Mountain Landscapes of North Karelia

Soils of low-mountain landscapes in the northwest of Karelia have been studied. The soil cover of the studied area is mainly represented by Al–Fe-humus soils (Podzols); thin soils (Leptosols) are widespread. Characteristic morphological features of all the studied soils are relatively shallow profiles, high stone content, and underlying by hard bedrock with fine earth material in crevices between large boulders. The studied soils have the high carbon and low nitrogen content, which points to unfavorable conditions of organic matter transformation. The content of most macro- and microelements is not high, which is typical for soils of the region; the content of copper and zinc exceeds the regional background two–three times. Regularities of the vertical zonality in the properties of soils of mountain ecosystems manifest themselves in decreasing thickness of the soil profile at higher altitude above sea level in parallel to decreasing thickness of the layer of loose rocks, while the stone content increases. In soils of the forest-tundra zone, the organomineral horizon with the high organic matter content is formed immediately under the forest litter. The litter horizon is the soils of this zone is characterized by increased concentrations of calcium, magnesium, phosphorus, and zinc.     

Forest floor development and biochemical properties in reconstructed boreal forest soils

Following resource extraction by surface mining in the oil sands region of northeastern Alberta, sites are reclaimed by reconstructing soils using a variety of salvaged organic and mineral materials, and planted to native tree species. This study assessed the influence of three distinct stand types (Populus tremuloides Michx., Pinus banksiana Lamb., and Picea glauca (Moench) Voss) on forest floor development (thickness, morphology, total carbon and nitrogen contents), soil organic matter composition, and associated soil microbial communities. Forest floor and top mineral soil (0–5 cm) samples were collected from 32 sites reclaimed 16–33 years ago. Soil organic matter composition was measured using ramped-cross-polarization ¹³C nuclear magnetic resonance, and microbial communities were characterized using phospholipid fatty acid analysis. Morphological characteristics indicated little mesofaunal or fungal activities within the forest floors. Stands dominated by P. tremuloides fostered more rapid forest floor development than the coniferous (P. banksiana and P. glauca) stands, and showed a significant increase in forest floor thickness with time since reclamation. Within the P. tremuloides stands, forest floor development was accompanied by temporal changes in soil organic matter composition that reflected inputs from the canopy. Soil microbial community composition differed among reclamation treatments of the reconstructed soils, specifically as a function of their subsoil mineral textures, when canopy cover was below 30%. Above 30%, significant differences became apparent among stand types. Taken together, our results document how canopy cover and stand type were both important factors for the reestablishment of plant–soil relationships at these sites. Furthermore, achieving a canopy cover of 30% emerged as a critical threshold point during soil reclamation.     

Contribution of Parker and Product indexes to evaluate weathering condition of Yellow Brown Forest soils in Japan

Soil weathering is recognizable through study on physico-chemical characteristics of soil. In this study, Parker, ([(Na)_a / 0.35] + [(Mg)_a / 0.9] + [(K)_a / 0.25] + [(Ca)_a / 0.7]) × 100, and Product, [SiO₂ / (TiO₂ + Fe₂O₃ + SiO₂ + Al₂O₃)] × 100, weathering indexes, originally developed for study on rocks, were tested on Yellow Brown Forest soils from two different regions in Japan. The results showed that the contribution of the mentioned indexes can be used for study on soils weathering. In other word, in a two-dimensional coordination system where the axes are Parker and Product indexes, regarding to the chemical bases of the indexes, initial and lateral products of weathering can be tracked at the same time.

Additionally, the indexes relations with soil color were studied after exposing the samples at a high temperature. Remarkable relationships between a* / b* ratio–parameters of psychometric chromaticness of color in CIE color standard system–and these two weathering indexes demonstrated that a* / b* ratio can be applied reliably to estimate the quantities of Parker and Product indexes in Yellow Brown Forest soils.     

Growth and Production of Aquatic Mosses in Acidified Lakes of Karelia Republic,Russia

Three small acidified lakes (pH of water 5.3–5.9) in Karelia Republic, northwestern Russia, were studied in respect to speciescomposition, phytomass, and morphometric characteristics of aquatic mosses in their dense carpet. The dense moss carpet inlake L1 (mainly, Sphagnum denticulatum Bird.) occurred at a depth of 5.0–7.5 m and covered about 50% of the bottom area. The monospecific moss carpets occurred in lake L2 (Warnstorfia exannulata s. lato) and lake L3 (Fontinalishypnoides Hartm.) at depths of 5.0–7.0 m and 4.5–5.5 m and covered 20 and 13% of the bottom, respectively. The moss phytomass was 43–53 g air-dry mass m^-2 in the lake L2 andlake L3, while it was much higher in lake L1 – 293 g m^-2.Seasonal changes in shoot morphology of S. denticulatum,W. exannulata s. lato and in size and density of leavesalong the shoot axis of F. hypnoides allowed to reconstructthe annual growth and to estimate of growth rates of the mossesin their natural habitat within dense carpet. The absolutely netproduction of the mosses was estimated on the basis of thesedata. In two lakes (L2 and L3), the annual means of absolutelynet production of the aquatic mosses were 32–41 g air-dry massm^-2 yr ^-1, while in the third lake (L1) they weremarkedly higher – 157 g m^-2. The obtained results andcharacteristics of aquatic mosses are compared with those formosses in acidified Lake Grane Langsø in Denmark.     

Water retention curves and chemical compositions of soil solutions from some soils of the Central Forest State Nature Biosphere Reserve

The water retention curves, pore size distributions, and chemical compositions of soil solutions were described for some soils of the Central Forest State Nature Biosphere Reserve. The threshold values of soil water content and applied negative pressure for obtaining a homogeneous soil solution from a specific category of soil pores were found. The effect of soil water on the chemical composition of soil solution was studied.     

Soil-geographical regionalization as a basis for digital soil mapping: Karelia case study

Recent development of digital soil mapping (DSM) allowed improving significantly the quality of soil maps. We tried to make a set of empirical models for the territory of Karelia, a republic at the North-East of the European territory of Russian Federation. This territory was selected for the pilot study for DSM for two reasons. First, the soils of the region are mainly monogenetic; thus, the effect of paleogeographic environment on recent soils is reduced. Second, the territory was poorly mapped because of low agricultural development: only 1.8% of the total area of the republic is used for agriculture and has large-scale soil maps. The rest of the territory has only small-scale soil maps, compiled basing on the general geographic concepts rather than on field surveys. Thus, the only solution for soil inventory was the predictive digital mapping. The absence of large-scaled soil maps did not allow data mining from previous soil surveys, and only empirical models could be applied. For regionalization purposes, we accepted the division into Northern and Southern Karelia, proposed in the general scheme of soil regionalization of Russia; boundaries between the regions were somewhat modified. Within each region, we specified from 15 (Northern Karelia) to 32 (Southern Karelia) individual soilscapes and proposed soil-topographic and soil-lithological relationships for every soilscape. Further field verification is needed to adjust the models.     

Chemical composition of solutions in macro- and micropores in the upper horizons of soils in the Central Forest State Biosphere Reserve

The average concentrations of Al, Si, Fe, Mn, Pb, Ni, V, Ba, and other elements were 1.5–3.5 times lower (in some cases, up to 60 times) in the macropores than in the micropores. The regularities found agreed with the rules of selective absorption of ions and their capability for the formation of complexes with the components of the soil solids. The behavior of Fe and Mn can be explained by the differences in the redox conditions in the pores of different sizes. The degree of the relationships between the soil solution and the solid phase of the matrix in the macro- and micropores differed by several orders of magnitude (within a pF range up to 4). This fact determined the different mobilization of the elements in the solutions of the macro- and micropores. The reserves of the elements were proportional not only to their concentrations but also to the amount of solution in the appropriate pores.     

The influence of afforestation and tree species on soil methane fluxes from shallow organic soils at the UK Gisburn Forest Experiment

There is growing evidence that land use is an important factor in influencing soil methane (CH₄) fluxes, and afforestation is viewed as a potential tool for mitigating CH₄ releases from soils. However, the influence of different tree species on soil CH₄ fluxes is not well understood. We measured soil CH₄ fluxes under four tree species and grassland on similar soils at the Gisburn Experimental Forest (NW England) at 2 weekly intervals over 12 months using a static chamber technique. The treatments were Norway spruce (Picea abies), Scots pine (Pinus sylvestris), oak (Quercus petraea), alder (Alnus glutinosa) and grassland. Positive soil CH₄ fluxes were observed from grassland plots (average 4.6 kg/ha/year) and negative fluxes from all four tree species (average of all tree species ?0.5 kg/ha/year). There were, however, no statistically significant differences between individual treatments. Soil water table depth and moisture content had the greatest influence on soil CH₄ fluxes. It is possible that the afforestation of shallow organic and/or poorly drained soils such as these may have a relatively low capacity for mitigating CH₄ fluxes. Although methanotrophic bacteria may exist (i.e. there is the potential for oxidation), they may not be able to dominate due to their requirements for specific environmental conditions.     

Phosphorus fractions in preferential flow pathways and soil matrix in hillslope soils in the Thuringian Forest (Central Germany)

Phosphorus (P) is primarily transported in soil through preferential flow pathways (PFP), which can rapidly move water and matter bypassing large portions of the soil. This study investigated the composition of P forms in PFPs and soil matrix in two profiles at a forested hillslope in the Thuringian Forest (Central Germany), in order to evaluate (1) the effect of PFPs on the distribution of P fractions in forest soils, and (2) how hillslope position influences P fractions and other chemical parameters. To characterize water and mass fluxes in the profiles, flow pathways were visualized using dye tracer experiments. Stained and unstained soil material was sampled to assess differences of chemical parameters in the PFPs and soil matrix, and tested for correlations between chemical parameters to determine the factors influencing P fractions in soils. The results revealed significantly higher P contents (total P and most P fractions) in the upslope profile compared to the downslope profile. This accumulation effect in the upper profile was also observed for C, N, Fe, and Mn. The distribution of flow patterns also differed between the two profiles with stronger vertical infiltration into mineral soil and more preferential flow along stones and roots in the upslope profile compared to the downslope profile. However, the observed difference could not be addressed to hillslope effects as both test plots were located in mid‐slope position, but were strongly influenced by spatial heterogeneity (e.g ., micro‐relief). Furthermore, no statistically significant accumulation effect of P or other elements in PFPs compared to soil matrix was found. At the test site, the combination of high stone content with low potential for P sorption, and predominance of near‐surface lateral flow, appears to have hampered the development of gradients in chemical parameters between PFPs and soil matrix.     

Structural-functional organization of the soil mesofauna population in bogs and waterlogged forests of northwestern Karelia

The soil mesofauna was studied in two ecological series (oligotrophic and mesotrophic) of bogs in northwestern Karelia. The earlier found differences in the structural-functional organization of the soil mesofauna in the bogs investigated were confirmed. The high indices of the taxonomic diversity and abundance of mesopedobionts were characteristic of the mesotrophic biogeocenoses. Among the factors limiting the activity of the mesopedobionts, the hydrothermal regime and soil acidity played the leading part. In the series of the bog biogeocenoses studied, the abundance of mesopedobionts increased with the increasing soil acidity, lowering the groundwater table and decreasing the content of sodium extracted by the ammonium acetate solution. Zoophages predominated in the trophic structure of the oligotrophic bogs due to the unfavorable conditions for large invertebrates there; in the mesotrophic bogs, myxophages were the dominants. The abundance of myxophages increased in the mesotrophic series simultaneously with the increasing nitrogen content in the soil mesofauna-inhabited soil horizons. In the mesotrophic biogeocenoses, saprophages were not numerous (one species of litter earthworms). Probably, in the bog soils, they are substituted for myxophages.     

Hard-setting soils

Abstract. Hard-setting soils are widespread in dry regions. Their properties are described and a physical explanation for hard-setting behaviour is given. The limitations on soil management and physical fertility caused by hard-setting depend on timing of rainfall or irrigation with respect to cultivations and crop development, and much research is needed to quantify reductions in crop yield imposed by these limitations.     

Comparative analysis of the composition of water extracts and soil solutions from peat gleyic podzolic soils of the Central Forest State Biosphere Reserve

The composition of soil solutions obtained by vacuum filtration from peat gleyic podzolic soils of the Central Forest State Biosphere Reserve under field conditions was determined. It was found that the composition and properties of the soil solutions reliably differ from those of the water extracts. The natural solutions are characterized by higher concentrations of metals (primarily of Na, K, Ca, and Cu), an increased content of the hydrophobic fraction of water-soluble substances, an order of magnitude lower carbon content, and lower values of the actual and potential acidity.     

不同类型森林水库调水特性研究

以福建闽江上游裸露地为对照,封山育林、杉木和木荷林分为研究对象,分别采用水量平衡法与混合数量化模型对森林水库的调节水总量动态变化及其影响因素进行研究,以期加深对森林水库调水机理的认识。结果表明:木荷、杉木、封山育林林分及对照森林水库2个水文年中调节水总量分别为3 106.27,3 090.41,3 074.05,1 935.29 mm,分别占同期降雨量的97.71%,97.21%,96.70%,60.88%。雨季不同类型森林水库调节水总量均占年内森林水库调节水总量的48%左右,而旱季调节水总量则仅占18%左右。降雨量、I30和林分类型对森林水库调节水总量的贡献率较高,其中降雨量与森林水库调节水总量呈正相关,影响最大,I30与森林水库调节水总量呈负相关,林分类型因子得分值为木荷(9.293)>杉木(8.466)>封山育林(6.545)>对照(0)。     

不同类型森林水库调水特性研究

以福建闽江上游裸露地为对照,封山育林、杉木和木荷林分为研究对象,分别采用水量平衡法与混合数量化模型对森林水库的调节水总量动态变化及其影响因素进行研究,以期加深对森林水库调水机理的认识。结果表明：木荷、杉木、封山育林林分及对照森林水库2个水文年中调节水总量分别为3106．27,3090．41,3074．05,1935．29mm,分别占同期降雨量的97．71％,97．21％,96．70％,60．88％。雨季不同类型森林水库调节水总量均占年内森林水库调节水总量的48％左右,而旱季调节水总量则仅占18％左右。降雨量、I30和林分类型对森林水库调节水总量的贡献率较高,其中降雨量与森林水库调节水总量呈正相关,影响最大,I30与森林水库调节水总量呈负相关,林分类型因子得分值为木荷（9．293）〉杉木（8．466）〉封山育林（6．545）〉对照（0）。     

北京市八达岭林场森林生态系统健康性评价

以野外实地调查为基础．在可操作性、科学性、可比性、可接受性原则指导下,采用复合结构功能指标法对八达岭林场各小班林分物种多样性、群落层次结构、郁闭度、灌木层盏度、年龄结构、林分蓄积量、土壤侵蚀程度、病虫害危害程度进行健康评价并划分4个等级,在林分尺度上森林的理想结构可简单表述为复层、异龄、混交林结构,具有比较发达的灌木层和草本层,并且具有较高的生物多样性和生物生产力。这样的结构具有较高的稳定性、抗干扰性和活力。是健康森林群落的理想结构,以此为八达岭林场森林健康经营提供科学的理论依据。