| 1. |
- Bergsten, Urban, et al.
(författare)
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Frost Heaving of Picea abies Seedlings as Influenced by Soil Preparation, Planting Technique, and Location along Gap-Shelterwood Gradients
- 2009
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 43, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- The effects or soil preparation, planting technique and location along gap-shelterwood gradients (position and orientation) oil frost heaving damage to seedlings were studied in Vindeln Experimental Forests, northern Sweden. The forest was harvested in a grid pattern in winter 2004-2005, forming gaps and shelterwood areas of 30x40 m each. Gap-shelterwood gradients were delimited in four orientations and subdivided into five positions: 7 ill and 15 m into the gap and shelterwood, and at the gap edge. At each position, three replicates of three soil preparations were made: exposed E and B horizons and HuMinMix (milled vegetation and humus layers mixed with surface mineral soil). In early October 2005, one-year-old containerized Picea abies (L.) Karst. seedlings were planted using four techniques: normal and deep planting, and mobile and fixed experimental containers. After one winter, frost heaving damage was highest for seedlings oil B horizon combined with the mobile container (51 +/- 6%) and normal planting (43 +/- 6%). Normal- or deep-planted seedlings in HuMinMix had the least damage (5-6.6 +/- 2.5%). Compared to normal planting, deep planting reduced frost heaving damage only on B horizon. When considering the orientation, seedlings in the experimental containers had more or similar frost heaving damage than normal- or deep-planted seedlings. Along the eastern gradient, seedlings incurred more frost heaving damage in the center of the gap than under the canopy.
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| 2. |
- Bergvall, Martin, et al.
(författare)
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Modeling subsurface transport in extensive glaciofluvial and littoral sediments to remediate a municipal drinking water aquifer
- 2011
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 15, s. 2229-2244
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Tidskriftsartikel (refereegranskat)abstract
- Few studies have been carried out that cover the entire transport process of pesticides, from application at the soil surface, through subsurface transport, to contamination of drinking water in esker aquifers. In formerly glaciated regions, such as Scandinavia, many of the most important groundwater resources are situated in glaciofluvial eskers. The purpose of the present study was to model and identify significant processes that govern subsurface transport of pesticides in extensive glaciofluvial and littoral sediments. To simulate the transport processes, we coupled a vadose zone model at soil profile scale to a regional groundwater flow model. The model was applied to a municipal drinking-water aquifer, contaminated with the pesticide-metabolite BAM (2,6-dichlorobenzoamide). At regional scale, with the combination of a ten-meter-deep vadose zone and coarse texture, the observed concentrations could be described by the model without assuming preferential flow. A sensitivity analysis revealed that hydraulic conductivity in the aquifer and infiltration rate accounted for almost half of the model uncertainty. The calibrated model was applied to optimize the location of extraction wells for remediation, which were used to validate the predictive modeling. Running a worst-case scenario, the model showed that the establishment of two remediation wells would clean the aquifer in four years, compared to nine years without them. Further development of the model would require additional field measurements in order to improve the description of macrodispersion in deep, sandy vadose zones. We also suggest that future research should focus on characterization of the variability of hydraulic conductivity and its effect on contaminant transport in eskers.
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| 3. |
- Casetou, Sophie, et al.
(författare)
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Current, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: a comparison of three methods
- 2020
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 17, s. 281-304
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Tidskriftsartikel (refereegranskat)abstract
- Reliable and accurate methods for estimating soil mineral weathering rates are required tools in evaluating the sustainability of increased harvesting of forest biomass and assessments of critical loads of acidity. A variety of methods that differ in concept, temporal and spatial scale, and data requirements are available for measuring weathering rates. In this study, causes of discrepancies in weathering rates between methods were analysed and were classified as being either conceptual (inevitable) or random. The release rates of base cations (BCs; Ca, Mg, K, Na) by weathering were estimated in podzolised glacial tills at two experimental forest sites, Asa and Flakaliden, in southern and northern Sweden, respectively. Three different methods were used: (i) historical weathering since deglaciation estimated by the depletion method, using Zr as the assumed inert reference; (ii) steady-state weathering rate estimated with the PROFILE model, based on quantitative analysis of soil mineralogy; and (iii) BC budget at stand scale, using measured deposition, leaching and changes in base cation stocks in biomass and soil over a period of 12 years. In the 050 cm soil horizon historical weathering of BCs was 10.6 and 34.1 mmolc m(-2) yr(-1), at Asa and Flakaliden, respectively. Corresponding values of PROFILE weathering rates were 37.1 and 42.7 mmolc m(-2) yr(-1). The PROFILE results indi- cated that steady-state weathering rate increased with soil depth as a function of exposed mineral surface area, reaching a maximum rate at 80 cm (Asa) and 60 cm (Flakaliden). In contrast, the depletion method indicated that the largest postglacial losses were in upper soil horizons, particularly at Flakaliden.With the exception of Mg and Ca in shallow soil horizons, PROFILE produced higher weathering rates than the depletion method, particularly of K and Na in deeper soil horizons. The lower weathering rates of the depletion method were partly explained by natural and anthropogenic variability in Zr gradients. The base cation budget approach produced significantly higher weathering rates of BCs, 134.6 mmolc m(-2) yr(-1) at Asa and 73.2 mmolc m(-2) yr(-1) at Flakaliden, due to high rates estimated for the nutrient elements Ca, Mg and K, whereas weathering rates were lower and similar to those for the depletion method (6.6 and 2.2 mmolc m(-2) yr(-1) at Asa and Flakaliden). The large discrepancy in weathering rates for Ca, Mg and K between the base cation budget approach and the other methods suggests additional sources for tree uptake in the soil not captured by measurements.
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| 4. |
- Fröberg, Mats, et al.
(författare)
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Long-term effects of experimental fertilization and soil warming on dissolved organic matter leaching from a spruce forest in Northern Sweden
- 2013
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 200-201, s. 172-179
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen deposition and increasing temperature are two of the major large-scale changes projected for coming decades and the effect of this change on dissolved organic matter is largely unknown. We have utilized a long-term fertilization and soil warming experiment in Northern Sweden to study the effects of increased nutrient levels and increased temperature on DOC transport under the O horizon. The site is N limited and mean annual temperature 2. °C. Experimental fertilization with ammonium nitrate and a physiological mixture of other macro- and micro-nutrients has been going on for 22. years and soil warming, 5. °C above ambient soil temperature for 14. years, prior to the study. Experimental plots have been irrigated to avoid drying and we also studied the effect of this long-term irrigation on DOC by establishing control plots receiving no irrigation.DOC concentrations and fluxes under the O horizon were approximately 50% higher in fertilized plots than in non-fertilized control plots. We did not find any statistically significant effect of soil warming. There was a statistically significant effect of long-term irrigation on DOC with higher DOC concentration and fluxes in irrigated plots than in plots without irrigation. There were no major effects on DOC quality measured by specific UV absorbance. Fertilization approximately doubled soil organic matter stocks in the O horizon, whereas there were no such effects of warming or irrigation on soil organic matter amounts. There was no statistically significant treatment effect on DOC collected from the B horizon. We hypothesize that the positive effect of fertilization on DOC is related to increased soil C stocks.
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| 5. |
- Grip, Harald
(författare)
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Sweden's first forest hydrology field study 1905-1926: contemporary relevance of inherited conclusions and data from the Rokliden Hillslope
- 2015
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 29, s. 3616-3631
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Tidskriftsartikel (refereegranskat)abstract
- During the last decades of the 19th century, a great worry arose about forest landscape paludification in Northern Sweden. This was the original impetus for forest hydrological research in Sweden, and the Swedish Institute of Experimental Forestry established the first field research site in 1905 at Rokliden, close to Pitea in North Sweden. It comprised 8.64ha located 2km down a 3-km-long gently sloping (similar to 4%), north facing Norway spruce covered till slope, interspersed with small mires. By 1931, it was concluded that paludification was not spreading across Northern Sweden at an appreciable rate. Within the Rokliden research site, 22 groundwater wells were installed and levels measured weekly until 1926. A map with 0.5m equidistance, ten vegetation classes, and soil profiles was established. Groundwater flow velocity was estimated by tracing added sodium chloride. Hydraulic conductivity was measured on undisturbed soil cores, while mechanical and chemical analyses were carried out on other samples. Groundwater was collected and analysed for dissolved compounds including oxygen. Hydrology was found important for soil types and vegetation development. The necessary profile drainage for podzol soil development was identified as vein drainage at the bedrock surface. Modern measurements in the re-established groundwater observation network and re-analysis of old data confirmed the plausibility of these original conclusions. Partial catchment area could explain rates of both groundwater level rise and recession. Revisiting this field study reveals that many issues in contemporary hillslope hydrology were already established a century ago, even though the provenance of that knowledge is not generally recognized. Copyright (c) 2014 John Wiley & Sons, Ltd.
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| 6. |
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| 7. |
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| 8. |
- Grip, Harald
(författare)
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Water chemistry and runoff in forest streams at Kloten
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Natural variability of stream water composition and discharge was studied in the Kloten area, Central Sweden, by means of statistical methods and simulation technique. The effects of Urea (155 kgN ha-1) and ammonium nitrate (AN, 160 kgN ha-1) fertilization and clear-cutting were studied by comparing treated and reference streams before and after management.The concentrations of the chemical constituents and runoff were mostly inhomogeneous in space and time and the coefficients of variation were considerable.Urea fertilization had a more prolonged nitrogen leaching and a total of 750 kgN km-2 compared with AN treated areas (500 kgN km-2). The difference was due to higher nitrate leaching. Base cation leaching was larger and pH increased after Urea fertilization. pH decreased after AN fertilization.Runoff increased 180 mm year-1 after clear-cutting, while no significant change was found after fertilization. The immediate effect of clear-cutting on stream water chemistry was an increase in dissolved organic matter, followed by increased leaching of ammonia (10x), nitrate (9x) and potassium (4.8x). The total excess leaching of nitrogen was 1 040 kgN km-2 during the first three years after clear-cutting.A Norwegian hydrochemical model, that explained stream water composition, was modified and parameterized (40 parameters) for two catchments to analyse differences between them.The differences in parameters between the catchments were interpreted as differences in slopes close to the drainage net, dilution due to different evaporation, differences in standing biomass and current annual increment and slightly different mineral composition of the soils. pH at high flows could be deduced from stand characteristics.
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| 9. |
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| 10. |
- Hedwall, Per-Ola, et al.
(författare)
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Effects of clear-cutting and slash removal on soil water chemistry and forest-floor vegetation in a nutrient optimised Norway spruce stand
- 2013
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 47
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Tidskriftsartikel (refereegranskat)abstract
- Fertilisation with nutrient optimisation has in Sweden resulted in large increases in volume growth in young stands of Norway spruce. There are, however, environmental concerns about repeated fertilisation and one is the risk of nutrient leakage to ground water resources and aquatic ecosystems after clear-cutting of such forests. The present study followed soil-water chemistry in optimised fertilised stands after clear-cutting, as well as effects of harvest of slash on nutrient leakage. Parts of a 30-year-old stand of Norway spruce, which had been subject to a nutrient optimisation experiment for 17 years, were clear-cut. A split-plot design with whole-tree harvesting as the sub-plot treatment was applied. Lysimeters were installed and soil-water sampled at nine occasions during the following four years. No significant effects of fertilisation on nitrate leaching were found, while harvest of slash affected the concentration of Ca, DOC, DON, K, Mg, ammonium and nitrate, as well as pH in the soil solution. While no effects of fertilisation could be seen on the soil water concentration of N, the results indicate an interaction between fertilisation and harvest of slash on the concentration of nitrate in the soil solution. The results indicate that forest-floor vegetation plays an important role in the retention of N after clear-cutting of fertilised forests.
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