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High latitude organic soils form a significant carbon storage and deposition of these soils is largely driven by climate. Svalbard, Norway, has experienced millennial-scale climate variations and in general organic soil processes have benefitted from warm and humid climate phases while cool late Holocene has been unfavourable. In addition to direct effect of cool climate, the advancing glaciers have restricted the vegetation growth, thus soil accumulation. Since the early 1900's climate has been warming at unprecedented rate, assumingly promoting organic soil establishment. Here we present results of multiple organic soil profiles collected from Svalbard. The profiles have robust chronologies accompanied by soil property analyses, carbon stock estimations and testate amoeba data as a proxy for soil moisture. Our results reveal relatively recent initiation of organic soils across the Isfjorden area. The initiation processes could be linked to glacier retreat, and improvement of growing conditions and soil stabilization. Carbon stock analyses suggested that our sites are hot spots for organic matter accumulation. Testate amoebae data suggested drying of soil surfaces, but the reason remained unresolved. If continued, such a process may lead to carbon release. Our data suggest that detailed palaeoecological data from the Arctic is needed to depict the on-going processes and to estimate future trajectories. [ABSTRACT FROM AUTHOR]

Aim: We aim to use species attributes such as distributions and indicator values to reconstruct past biomes, environment, and temperatures from detailed plant‐macrofossil data covering the late glacial to the early Holocene (ca. 14–9 ka). Location: Kråkenes, western Norway. Methods: We applied attributes for present‐day geographical distribution, optimal July and January temperatures, and Ellenberg indicator values for plants in the macrofossil data‐set. We used assemblage weighted means (AWM) to reconstruct past biomes, changes in light (L), nitrogen (N), moisture (F), and soil reaction (R), and temperatures. We compared the temperature reconstructions with previous chironomid‐inferred temperatures. Results: After the start of the Holocene around 11.5 ka, the Arctic‐montane biome, which was stable during the late‐glacial period, shifted successively into the Boreo‐arctic montane, Wide‐boreal, Boreo‐montane, Boreo‐temperate, and Wide‐temperate biomes by ca. 9.0 ka. Circumpolar and Eurasian floristic elements characteristic of the late‐glacial decreased and the Eurosiberian element became prominent. Light demand (L), soil moisture (F), nitrogen (N), and soil reaction (R) show different, but complementary responses. Light‐demanding plants decreased with time. Soil moisture was relatively stable until it increased during organic soil development during the early Holocene. Soil nitrogen increased during the early Holocene. Soil reaction (pH) decreased during the Allerød, but increased during the Younger Dryas. It decreased markedly after the start of the Holocene, reaching low but stable levels in the early Holocene. Mean July and January temperatures show similar patterns to the chironomid‐inferred mean July temperature trends at Kråkenes, but chironomids show larger fluctuations and interesting differences in timing. Conclusion: Assigning attributes to macrofossil species is a useful new approach in palaeoecology. It can demonstrate changes in biomes, ecological conditions, and temperatures. The late‐glacial to early‐Holocene transition may form an analogue for changes observed in the modern arctic and in mountains, with melting glaciers, permafrost thaw, and shrub encroachment into tundra. [ABSTRACT FROM AUTHOR]

Total and soluble nutrients in peat were studied after ash fertilization on an oligotroph peatland in southeast Norway. Plots 15 m × 15 m in size were fertilized with 0, 4, 7, and 10 tons ha1 of wood or peat ash in 1944. Chemical analyses after 18, 35 and 48 years showed a gradual reduction of phosphorus (P) and calcium (Ca) from the 0 to 10 cm surface peat layer. Some of the leached Ca was recovered in the layers 10–20 and 20–40 cm, while hardly any of the lost P was recovered in this way. The amount of potassium (K) in the surface layer declined by 75% over the first 18 years, and remained stable thereafter. Nothing of the lost K was recovered in deeper layers. The pH reflected the Ca levels. Over the years, an increasing proportion of the applied P, K and Ca was retrieved in the trees. Needle analyses indicated that declining tree vigor on plots fertilized with 4 and 7 tons of ash ha−1 was due to P limitations. After 48 years, the peat content of P and Ca was still significantly higher in fertilized than in control plots, thus demonstrating the long-lasting effect of ash fertilization. [ABSTRACT FROM AUTHOR]

This study examines biomass accumulation in a spruce stand in the Cindrel Mountains under the influence of soil type. The research has been carried out in the Cindrel Mountains, Onceşti District. Two surfaces were analized, located at similar altitude, with similar climatic conditions and vegetation, but developed on different soils. The aim of the research was to establish a link between humus type and amount of biomass accumulated by forest species. In experimental plots soil samples were collected on which were made measurements of the morphological, physical and chemical properties, and an inventory of the forest vegetation to which it was integral. We aimed to characterize the soil in terms of pH, degree of base saturation, nitrogen, type of humus and edaphic useful volume. The determinations of the trees covered the height, diameter and some quality indicators. Other observation focused on the replicability of the forest site and indicator flora. The results obtained allowed us to draw conclusions based on statistical processing. [ABSTRACT FROM AUTHOR]

Abstract: The distribution of organic carbon and its relationship to vegetation development were examined on a glacier foreland near Ny-Ålesund, Svalbard (79°N). In a 0.72-km2 area, we established 43 study plots on three line transects along primary succession from recently deglaciated area to old well-vegetated area. At each plot, we measured the type and percent coverage of vegetation types. The organic carbon content of vegetation, organic soil, and mineral soil samples was determined based on their organic carbon concentration and bulk density. Cluster analysis based on vegetation coverage revealed five types of ground surfaces representing variations in the amounts and allocation patterns of organic carbon. In the later stages of succession, 7%–24% and 31%–40% of organic carbon was contained in the organic and deeper soil layers, respectively. Organic carbon storage in the later stages of succession ranged from 1.1 – 7.9 kg C m−2. A larger amount of organic carbon, including ancient carbon in a raised beach deposit, was expected to be contained in much deeper soil layers. These results suggest that both vegetation development and geological history affect ecosystem carbon storage and that a non-negligible amount of organic carbon is distributed in this High Arctic glacier foreland. [Copyright &y& Elsevier]

Transport and turnover of dissolved organic carbon (DOC) is important in the C cycle of organic soils. The concentration of DOC in soil water is buffered by adsorption to the soil matrix, and has been hypothesized to depend on the pool size of adsorbed DOC. We have studied the effect of frequent artificial excessive leaching events on concentration and flux of DOC in shallow, organic rich mountain soils. Assuming a constant Kd value for DOC adsorption to the soil matrix, we used these data to assess the change in the pool of adsorbed (or potential) DOC in the soil. The study involved manipulation of precipitation amount and frequency in summer and autumn in small, heathland catchments at Storgama, southern Norway. The shallow soils (16–34 cm deep on average) limit the possibility for changes in water flow paths during events. The mini-catchments range in size from 75 to 98 m2. Our data show that after leaching of about 1.2 g DOC m−2 the DOC concentration in runoff declines by approximately 50%. From this we conclude that the pool size of adsorbed potential DOC in the shallow soils at any time is of the order 2–3 g m−2. Frequent episodes suggest that the replenishment rate, which depends on the decomposition rate of soil organic matter, is fast and the potential DOC pool could be fully restored probably within days during summer, but with some more time required in autumn, due to lower temperatures. Both pool size of potential DOC and replenishment rate are seasonally dependent. The pool of potential DOC, and thus the DOC concentration in discharge, is at their maximum in the growing season. However, under non-leaching conditions, the concentration of DOC in soil water and thus the pool size of potential DOC seems to level off, possibly due to conversion of DOC to less reversibly bound forms, or to further decomposition to CO2. [ABSTRACT FROM AUTHOR]

Abstract: A number of different research approaches have been used to investigate the influence of tree species on the particular ecological parameters in mixed forest stands. While it is widely recognized that trees have species-specific effects on particular resources like radiation, water and nutrients more interacting effects of mixtures are assumed to exist. In this paper we examine the spatial variation of humus mass in a mixed stand and discuss the influence of specific spatial factors on humus mass variation. Our study site is located in the Solling area, an intermediate mountain range in the south of Lower Saxony in Germany. It is located in a 130–140-year-old European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L). Karst.) mixed stand. To better understand processes which determine amount of humus mass variation within mixed stands of European beech and Norway spruce we measured humus mass of the OF and ecological factors at sample points (litter fall of beech and spruce, radiation, and precipitation beneath the forest canopy). We used a structural equation model (SEM) to analyse data for the effect of species-specific litter input, radiation and throughfall on humus mass variation. Additional to classical regression approaches SEM enables us to consider latent, non-observed, factors or variables. In this paper we present a special SEM, a so-called linear structural relationship (LISREL) model, showing how self-formulated latent variables like “decomposition environment” and “decomposition inhibition” affect the humus mass of the OF layer. Latent structures are of great importance in order to understand and analyse processes determining humus mass variation. In our model, “latent variables” are identified, which explain the contribution of measured variables to improvement or deterioration of humus decomposition, and hence more or less accumulation of organic material in the surface humus layers, in our case the OF layer. Spruce needle input impedes humus dynamics, while beech leaf litter input and higher throughfall amounts show supporting effects. These model results are in agreement with formerly reported findings, but yield further an interval-scaled combined measure which is better founded and more comprehensive than earlier descriptive approaches to the single ecological factors involved. Besides of the ecological interpretation of the results we succeed in determining a valid structural equation model taking into account all relevant ecological factors of humus decomposition. [Copyright &y& Elsevier]

In terms of agricultural use, peat soils have weak structure, high water content, insufficient soil aeration and poor thermal properties resulting in suboptimal physical properties and yields of grass. During the period 1978–1995, a long-term field trial was conducted on highly decomposed peat soil in order to investigate the impact of adding mineral materials to improve soil characteristics and increase grass yield. Shell sand or moraine soil (200, 400 or 800 m 3 ha -1 ) was incorporated into peat soil. Generally, addition of both shell sand and moraine soil improved the physical properties of the soil and grass production. During the first nine years, shell sand (400 m 3 ha - 1) was the most efficient. Thereafter, moraine soil (400 and 800 m 3 ha -1 ) seemed most beneficial. This study indicates that additions of shell sand or moraine soil to peat are appropriate methods to improve and conserve the physical properties and cropping potential of these vulnerable soils. [ABSTRACT FROM AUTHOR]

The role of organic soil as a sink for radioactive contaminants in a High Arctic environment was studied. Samples were obtained from an area of organic soil located on the Arctic archipelago of Svalbard (79° N) and from a non-organic control site in the same region. Samples were differentiated into organic layers and the underlying material and measured for a suite of anthropogenic and natural radionuclides and for a variety of soil chemistry parameters. Results indicated that the organic components of the soil constitute a sink term for a number of radionuclides. Values for Pu isotopes, 137Cs and 238U were appreciably higher at the study site than at the control site, by up to a factor of 40 for Pu and 20 for 137Cs and 238U. The source of 238U to the site appeared to be enrichment of this isotope from surface or melt water via adsorption to to either iron hydroxides or organic matter although the situation pertaining to Pu and 137Cs remains less clear. [ABSTRACT FROM AUTHOR]

The effects of additions of ammonium sulfate (NS) on the decomposition of litter derived from Norway spruce roots (< 2 and 2 - 5 mm in diameter) in the humus and mineral soil layers (0 - 15 cm) of a Norway spruce stand in southern Sweden were investigated over a 6-year period. To this purpose, litterbags were incubated in the humus layer and in the mineral soil in June 1996, with roots collected from NS and control (C) plots incubated in the NS and C plots, respectively. The N concentrations in fine roots (< 2 mm) in the NS- plots were higher than those in 2 - 5 mm roots in both humus and mineral soil layers. In the humus layer, N concentrations in the fine roots in the C- and NS- plots were 12.8 and 15.7 mg g  - 1 , respectively. By the end of the fifth year the < 2 mm roots in humus layer had lost 48.5 and 50% of their mass in the C and NS plots, respectively, while the corresponding values for the 2 - 5 mm diameter class were 44 and 54%. The fresh root litter may be a sensitive indicator to responses to enhanced N and S deposition, although decomposition rates of both litter types are affected. [ABSTRACT FROM AUTHOR]

Sorption–desorption kinetic and isotherm studies were performed by the batch equilibrium technique in three Norwegian soils. The soils were a fine sandy loam, a loam, and a soil of highly decomposed organic material. Two commercially formulations were used, Triagran‐P and Tilt, containing either a mixture of bentazone [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide], dichlorprop [(R)‐2‐(2,4‐dichlorophenoxy)‐propionic acid], and MCPA [(4‐chloro‐2‐methylphenoxy)acetic acid], or propiconazole [(±)1‐(2‐(2,4‐dichlorophenyl)‐4‐propyl‐1,3‐dioxolan‐2‐ylmethyl)‐1H‐1,2,4‐triazole] alone. Sorption–desorption equilibrium occurred within 10 h for all pesticides. The Freundlich isotherms indicated nonlinear sorption of bentazone, dichlorprop, MCPA, and propiconazole. For all pesticides the highest Freundlich adsorption coefficient (KF) values were in the soil with highest organic content and lowest pH. For the fine sandy loam and loam, which are representative Norwegian agricultural soils, the results indicate that bentazone, dichlorprop, and MCPA are mobile with KF values ranging from 0.07 to 1.50 mg1−1/n kg−1 L1/n Propiconazole is much less mobile with KF values ranging from 27.00 to 36.02 mg1−1/n kg−1 L1/n in the agricultural soils. [ABSTRACT FROM AUTHOR]

. The biomass and chemical composition in six dominant field and bottom layer species was followed during four years after a fire in a Pinus sylvestris forest in western Norway. Three fire intensity levels were distinguished: low, medium and high. The overall biomass in the different species was estimated from the biomass per shoot, the shoot densities in pure stands of the investigated species and the percentage cover at medium burned sites. Corresponding measurements were made at control plots outside the burned area. A strong post-fire increase in the overall biomass of Calluna vulgaris, Polytrichum spp., Deschampsia flexuosa and Pteridium aquilinum was found, against a much slower regrowth of Vaccinium myrtillus and V. vitis-idaea. The Vaccinium species and Calluna were the dominant species at the control plot. Accumulation of carbohydrates seemed to take place in green and non-green tissue of Pteridium and Deschampsia. A corresponding accumulation of nitrogen was found in green and non-green Calluna and in non-green Vaccinium myrtillus tissue, and of phosphorus in green and non-green tissue of both Vaccinium species and Calluna as a result of fire. The regrowth of Calluna was mainly from seeds that appeared to be present in the soil before the fire. The regeneration of Pteridium and the two Vaccinium species took place almost exclusively vegetatively from below-ground rhizomes that had survived the fire. Three years after the fire the overall biomass at the burned site was higher than at the control site, due to improved light and nutrient conditions. However, the biomass is expected to decrease in the future and the species composition will probably change as nutrients are leached out of the soil and Pinus and deciduous trees ( Betula pubescens and Salix caprea) regenerate from seeds and roots, leading to increased competition in the field and shrub layer. [ABSTRACT FROM AUTHOR]

Cultivated organic soils account for ~7% of Norway's agricultural land area, and they are estimated to be a significant source of greenhouse gas (GHG) emissions. The project 'Climate smart management practices on Norwegian organic soils' (MYR), commissioned by the Research Council of Norway (decision no. 281109), aims to evaluate GHG (e.g. carbon dioxide, methane and nitrous oxide) emissions and impacts on biomass productivity from three land use types (cultivated, abandoned and restored) on organic soils. At the cultivated sites, impacts of drainage depth and management intensity will be measured. We established experimental sites in Norway covering a broad range of climate and management regimes, which will produce observational data in high spatiotemporal resolution during 2019-2021. Using state-of-the-art modelling techniques, MYR aims to predict the potential GHG mitigation under different scenarios. Four models (BASGRA, DNDC, Coup and ECOSSE) will be further developed according to the soil properties, and then used independently in simulating biogeochemical processes and biomass dynamics in the different land uses. Robust parameterization schemes for each model will be based in the observational data from the project for both soil and crop combinations. Eventually, a multi-model ensemble prediction will be carried out to provide scenario analyses by 2030 and 2050. By integrating experimental results and modelling, the project aims at generating useful information for recommendations on environment-friendly use of Norwegian peatlands. [ABSTRACT FROM AUTHOR]