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  • 1. Ahmed, Engy
    et al.
    Hugerth, Luisa W.
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Logue, Jürg Brendan
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Bruchert, Volker
    Andersson, Anders F.
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Holmström, Sara J. M.
    Mineral Type Structures Soil Microbial Communities2017In: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 34, no 6, p. 538-545Article in journal (Refereed)
    Abstract [en]

    Soil microorganisms living in close contact with minerals play key roles in the biogeochemical cycling of elements, soil formation, and plant nutrition. Yet, the composition of microbial communities inhabiting the mineralosphere (i.e., the soil surrounding minerals) is poorly understood. Here, we explored the composition of soil microbial communities associated with different types of minerals in various soil horizons. To this effect, a field experiment was set up in which mineral specimens of apatite, biotite, and oligoclase were buried in the organic, eluvial, and upper illuvial horizons of a podzol soil. After an incubation period of two years, the soil attached to the mineral surfaces was collected, and microbial communities were analyzed by means of Illumina MiSeq sequencing of the 16S (prokaryotic) and 18S (eukaryotic) ribosomal RNA genes. We found that both composition and diversity of bacterial, archaeal, and fungal communities varied across the different mineral surfaces, and that mineral type had a greater influence on structuring microbial assemblages than soil horizon. Thus, our findings emphasize the importance of mineral surfaces as ecological niches in soils.

  • 2. Baken, S.
    et al.
    Larsson, M. A.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Cubadda, F.
    Smolders, E.
    Ageing of vanadium in soils and consequences for bioavailability2012In: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 63, no 6, p. 839-847Article in journal (Refereed)
    Abstract [en]

    Total vanadium (V) concentrations in soils commonly range from 20 to 120 mg kg-1. Vanadium added directly to soils is more soluble than geogenic V and can be phytotoxic at doses within this range of background concentrations. However, it is unknown how slow sorption reactions change the fate and effect of added V in soils. This study addresses the changes in V solubility, toxicity and bioavailability in soils over time. Four soils were amended with pentavalent V in the form of a soluble vanadate salt, and extractable V concentrations were monitored over 100 days. The toxicity to barley and tomato plants was evaluated in freshly spiked soils and in the corresponding aged soils that were equilibrated for up to 330 days after spiking. The V concentrations in 0.01 m CaCl2 soil extracts decreased approximately two-fold between 14 and 100 days after soil spiking, and the reaction kinetics were similar for all soils. The phytotoxicity of added V decreased on average two-fold between freshly spiked and aged soils. The reduced toxicity was associated with a corresponding decrease in V concentrations in the isolated soil solutions and in the shoots. The V speciation in the soil solution of the aged soils was dominated by V(V); less than 8% was present as V(IV). Oxalate extractions suggest that the V(V) added to soils is predominantly sorbed onto poorly crystalline oxyhydroxides. It is concluded that the toxicity of V measured in freshly spiked soils may not be representative of soils subject to a long-term V contamination in the field.

  • 3. Campos Pereira, H.
    et al.
    Ullberg, M.
    Kleja, D. B.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Swedish University of Agricultural Sciences, Sweden.
    Ahrens, L.
    Sorption of perfluoroalkyl substances (PFASs) to an organic soil horizon – Effect of cation composition and pH2018In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 207, p. 183-191Article in journal (Refereed)
    Abstract [en]

    Accurate prediction of the sorption of perfluoroalkyl substances (PFASs) in soils is essential for environmental risk assessment. We investigated the effect of solution pH and calculated soil organic matter (SOM) net charge on the sorption of 14 PFASs onto an organic soil as a function of pH and added concentrations of Al3+, Ca2+ and Na+. Often, the organic C-normalized partitioning coefficients (KOC) showed a negative relationship to both pH (Δlog KOC/ΔpH = −0.32 ± 0.11 log units) and the SOM bulk net negative charge (Δlog KOC = −1.41 ± 0.40 per log unit molc g−1). Moreover, perfluorosulfonic acids (PFSAs) sorbed more strongly than perfluorocarboxylic acids (PFCAs) and the PFAS sorption increased with increasing perfluorocarbon chain length with 0.60 and 0.83 log KOC units per CF2 moiety for C3–C10 PFCAs and C4, C6, and C8 PFSAs, respectively. The effects of cation treatment and SOM bulk net charge were evident for many PFASs with low to moderate sorption (C5–C8 PFCAs and C6 PFSA). However for the most strongly sorbing and most long-chained PFASs (C9–C11 and C13 PFCAs, C8 PFSA and perfluorooctane sulfonamide (FOSA)), smaller effects of cations were seen, and instead sorption was more strongly related to the pH value. This suggests that the most long-chained PFASs, similar to other hydrophobic organic compounds, are preferentially sorbed to the highly condensed domains of the humin fraction, while shorter-chained PFASs are bound to a larger extent to humic and fulvic acid, where cation effects are significant.

  • 4. Coucheney, E.
    et al.
    Eckersten, H.
    Hoffmann, H.
    Jansson, Per Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Gaiser, T.
    Ewert, F.
    Lewan, E.
    Key functional soil types explain data aggregation effects on simulated yield, soil carbon, drainage and nitrogen leaching at a regional scale2018In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 318, p. 167-181Article in journal (Refereed)
    Abstract [en]

    The effects of aggregating soil data (DAE) by areal majority of soil mapping units was explored for regional simulations with the soil-vegetation model CoupModel for a region in Germany (North Rhine-Westphalia). DAE were analysed for wheat yield, drainage, soil carbon mineralisation and nitrogen leaching below the root zone. DAE were higher for soil C mineralization and N leaching than for yield and drainage and were strongly related to the presence of specific soils within the study region. These soil types were associated to extreme simulated output variables compared to the mean variable in the region. The spatial aggregation of these key functional soils within sub-regions additionally influenced the DAE. A spatial analysis of their spatial pattern (i.e. their presence/absence, coverage and aggregation) can help in defining the appropriate grid resolution that would minimize the error caused by aggregating soil input data in regional simulations.

  • 5.
    Cucarella Cabañas, Victor
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Recycling Filter Substrates used for Phosphorus Removal from Wastewater as Soil Amendments2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis studied the viability of recycling filter substrates as soil amendments after being used in on-site systems for phosphorus (P) removal from wastewater. Focus was put on the materials Filtra P and Polonite, which are commercial products used in compact filters in Sweden. A prerequisite for this choice was to review filter materials and P sorption capacity. The filter substrates (Filtra P, Polonite and wollastonite tailings) were recycled from laboratory infiltration columns as soil amendments to a neutral agricultural soil and to an acid meadow soil to study their impacts on soil properties and yield of barley and ryegrass. The amendments tended to improve the yield and showed a liming effect, significantly increasing soil pH and the availability of P. In another experiment, samples of Filtra P and Polonite were equilibrated in batch experiments with the two soils in order to study the P dynamics in the soil-substrate system.  Batch equilibrations confirmed the liming potential of Filtra P and Polonite and showed that improved P availability in soils was strongly dependent on substrate P concentration, phase of sorbed P, and soil type. Finally, samples of Polonite used for household wastewater treatment were recycled as soil amendments to a mountain meadow and to an agricultural field for wheat cropping. The liming effect of Polonite was confirmed under field conditions and the results were similar to those of lime for the mountain meadow soil. However, the results were quite different for the agricultural field, where Polonite did not affect soil pH or any other chemical and physical soil properties investigated and had no impact on wheat yield and quality. The results from field experiments suggested that Polonite can be safely recycled to meadows and cropping fields at rates of 5-10 ton ha-1 but long-term studies are needed to forecast the effects of accumulation.

  • 6.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Zaleski, T.
    Mazurek, R.
    Recycling of calcium-silicate material after wastewater filtration to agriculture -Soil condition impact2012In: Ecological Chemistry and Engineering S, ISSN 1898-6196, Vol. 19, no 3, p. 373-382Article in journal (Refereed)
    Abstract [en]

    Reactive filter materials aimed at phosphorus (P) recovery is a novel method for on-site wastewater treatment. Once the bed filter is no longer effective, the sorbent must be replaced and can then be recycled as a soil amendment to agriculture. This study investigated the short-term effects of such amendments in a field with a wheat crop in order to evaluate the risks and/or potential benefits of this disposal option. The developed product Polonite (manufactured from Opoka) was used as a model filter sorbent in the field trial. Rates corresponding to approximately 6 and 8 tons per hectare were applied. In the short-term, this amending did not affect soil physical and sorption properties. The rate of Polonite used here, as P source for wheat was irrelevant in this kind of soil. The usefulness of this disposal option of exhausted filter material is discussed.

  • 7.
    Dong, Qian
    KTH, Superseded Departments, Materials Science and Engineering.
    Studies of transport in some oxides by gas phase analysis2004Licentiate thesis, comprehensive summary (Other scientific)
  • 8.
    Earon, Robert
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Initial Effects of a New Highway Section on Soil and Groundwater2012In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 223, no 8, p. 5413-5432Article in journal (Refereed)
    Abstract [en]

    The environmental impacts of 16 different contaminants originating from the E18 Highway (17,510 annual average daily traffic) were studied over the initial months of the highway's operational life. Investigative methods used included electrical resistivity surveying, water chemistry analyses, soil analyses, distribution modeling, and transportation modeling of contaminants. The study conclusively showed a year-round infiltration due to melting of the snowpack from road salt, and a strong preferential, anthropogenic pathway due to increased hydraulic conductivities of road construction materials relative to in situ soils. The resistivity surveys produced values well below the expected values for the highway materials, indicating increased ionic content within the unsaturated zone. Time lapse resistivity modeling showed a clear downwards spreading of contamination from the roadway to subsurface distances greater than 5 m. Elevated concentrations of nearly every studied contaminant relative to baseline values were observed, with many metal concentrations within the snow pack averaging values in excess of the Swedish Environmental Protection Agency's groundwater limitations. Distribution modeling demonstrated a potential offset of peak values from the road surface due to plowing and splash transport processes, and indicated different distribution behavior during winter months than during summer months. One-dimensional transport modeling demonstrated the importance of adsorption and other retentive factors to the migration of contaminants to groundwater and provided an estimate for potential long-term contaminant concentrations.

  • 9. Eriksson, Ann Kristin
    et al.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Swedish University of Agricultural Sciences, Sweden.
    Hesterberg, Dean
    Phosphorus speciation of clay fractions from long-term fertility experiments in Sweden2015In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 241, p. 68-74Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) losses from agricultural soils constitute a main driver for eutrophication of the Baltic Sea. There is limited knowledge about sorption and release processes of P in these soils, especially concerning the effects of fertilization. In this study, P speciation of the clay fractions from six different soils in long-term fertility experiments in Sweden was investigated by P K-edge XANES spectroscopy. As expected, unfertilized soils had lower concentrations of acid-digestible P compared with fertilized soils. Based on best-fit standards that emerged from linear combination fitting (LCF) of XANES spectra, phosphate sorbed on iron (Fe) (hydr)oxides was a dominant P species in clay fractions from unfertilized soils containing more than 35 mmol kg(-1) of oxalate-extractable Fe. In contrast, P sorbed on aluminum (Al) (hydr)oxides predominated in soils with lower concentrations of oxalate-extractable Fe. A greater proportion of organically bound P was fit for soil samples containing >2% organic carbon. The soils included one calcareous soil for which a greater proportion of P was fit as apatite. After long-term fertilization, P had accumulated mainly as P adsorbed to Al (hydr) oxides according to the XANES analysis. Our research shows that P speciation in fertilized agricultural soils depended on the level of P buildup and on the soil properties.

  • 10. Eriksson, Ann Kristin
    et al.
    Hillier, Stephen
    Hesterberg, Dean
    Klysubun, Wantana
    Ulén, Barbro
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Swedish University of Agricultural Sciences, Sweden.
    Evolution of phosphorus speciation with depth in an agricultural soil profile2016In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 280, p. 29-37Article in journal (Refereed)
    Abstract [en]

    With time, different soil-forming processes such as weathering, plant growth, accumulation of organic matter, and cultivation are likely to affect phosphorus (P) speciation. In this study, the depth distribution of P species was investigated for an agricultural clay soil, Lanna, Sweden. Small amounts of apatite-P was demonstrated in the topsoil whereas the speciation of Pat 70-100 cm depth consisted of approximately 86% apatite according to P K-edge XANES (X-ray absorption near-edge structure) spectroscopy. Because there were only minor differences in bulk mineralogy and texture, these variations in P speciation were interpreted as the result of apatite weathering of the topsoil. Speciation modeling on soil extracts supported this idea: hydroxyapatite was not thermodynamically stable in the top 50 cm of the soil. Apatite was enriched in the bulk soil relative to the clay fraction, as expected during apatite dissolution. Combined results from batch experiments, XANES spectroscopy and X-ray diffraction suggested chemical transformations of the topsoil as a result from accumulation of organic matter and airing from tillage followed by enhanced weathering of apatite, amphiboles, clay minerals, and iron oxides. This caused the formation of poorly crystalline secondary iron and aluminum (hydr)oxides in the topsoil, which retained part of the released P from apatite. Other P was incorporated into organic forms. Furthermore, the results also showed that short-term acidification below the current pH value (below 5.5 in the topsoil and 7.2 in the deeper subsoil) caused significant solubilization of P. This is attributed to two different mechanisms: the instability of Al-containing sorbents (e.g. Al hydroxides) at low pH (in the topsoil), and the acid-mediated dissolution of apatite (the subsoil).

  • 11.
    Eveborn, David
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Bed filters for phosphorus removal in on-site wastewater treatment: Removal mechanisms and sustainability2010Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    For many surface waters, phosphorus (P) leaching is a serious problem that should be minimized to prevent eutrophication. In Sweden there is a demand for physical and technical development of high-performance P removal techniques to reduce phosphorus leaching from on-site wastewater treatment systems to the Baltic Sea. However, although these systems are designed to reduce eutrophication there are also other environmental impacts to be considered when implementing them in on-site systems; energy use and global warming potential are two examples. This study has investigated several bed filter materials (reactive media and natural soils) for their total environmental impact (in commercial applications) as well as for the predominating chemical phosphorus removal mechanisms. The use of life cycle assessment revealed that several reactive bed filters are relatively energy-consuming due to the material manufacturing process. Characterization of phosphorus compounds in used reactive media provided evidence for calcium phosphate precipitation as the predominating P removal mechanism in alkaline filter materials. However, in soil treatment systems with noncalcareous soils, batch experiments and extractions suggested that aluminium compounds were important for P removal. According to mass balance calculations that compared accumulated P with the estimated P load in a soil treatment system, the long term P removal capacity was very low; only 6.4 % of the applied phosphorus had been removed during 16 years of operation.

  • 12.
    Eveborn, David
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
    Hesterberg, Dean
    University Raleigh, Department of Soil Science, North Carolina, USA.
    Hillier, Stephen
    Macaulay Institute, Craigiebuckler, Aberdeen, UK.
    XANES Speciation of P in Environmental Samples: An Assessment of Filter Media for on-Site Wastewater Treatment2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 17, p. 6515-6521Article in journal (Refereed)
    Abstract [en]

    X-ray absorption near edge structure (XANES) spectroscopyis a useful technique for characterization of chemical speciesof phosphorus in complex environmental samples. To developand evaluate bed filters as sustainable on-site wastewater treatment solutions, our objective in this study was to determine the chemical forms of accumulated phosphorus in a selectionof promising filter materials: Filtralite P, Filtra P, Polonite, Absol, blast furnace slag, and wollastonite. Full-scale operational wastewater-treatment systems were sampled and in addition, filter samples collected from laboratory studies provided access to additional media and complementary samples.Phosphorus species were characterized using phosphorus K-edge XANES spectroscopy, complemented by X-ray powder diffraction (XRPD) and attenuated total reflectance Fouriertransform infrared spectroscopy (ATR-FTIR). No systematic differences could be seen in the results between laboratory and full-scale samples. All six filter media contained significant amounts of crystalline calcium phosphates. Some samples also contained amorphous calcium phosphate (>60 % of totalP in Absol). In Filtralite P and blast furnace slag, more than 35 % of the accumulated phosphorus was associated with Fe or Al. Both the power and shortcomings of XANES analysis for characterizing P species in these filter media are discussed.

  • 13.
    Eveborn, David
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Kong, Deguo
    Department of Applied Environmental Science, Stockholm University, Sweden.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Wastewater treatment by soil infiltration: Long-term phosphorus removal2012In: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 140, p. 24-33Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) leaching from on-site wastewater treatment systems may contribute to eutrophication. In developed countries the most common on-site treatment technique is septic systems with soil infiltration. However, the current knowledge about long term P removal in soil treatment systems is not well developed and the data used for estimation of P losses from such systems are unreliable. In this study we sampled four filter beds from community-scale soil treatment systems with an age of between 14 and 22 years to determine the long-term P removal and to investigate the chemical mechanisms behind the observed removal. For one site the long-term P removal was calculated using a mass balance approach. After analysis of the accumulated P. it was estimated that on average 12% of the long-term P load had been removed by the bed material. This indicates a low overall capacity of soil treatment systems to remove phosphorus. Batch experiments and chemical speciation modelling indicated that calcium phosphate precipitation was not an important long-term P removal mechanism, with the possible exception of one of the sites. More likely, the P removal was induced by AlPO4 precipitation and/or sorption to poorly ordered aluminium compounds, as evidenced by strong relationships between oxalate-extractable Al and P.

  • 14. Fröberg, M.
    et al.
    Grip, H.
    Tipping, E.
    Svensson, Magnus
    Swedish University of Agricultural Sciences, Department of Soil and Environment, P.O. Box 7014, SE-75007 Uppsala, Sweden.
    Strömgren, M.
    Kleja, D. B.
    Long-term effects of experimental fertilization and soil warming on dissolved organic matter leaching from a spruce forest in Northern Sweden2013In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 200-201, p. 172-179Article in journal (Refereed)
    Abstract [en]

    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.

  • 15.
    Gustafsson, Jon Petter
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Mwamila, Luhuvilo B.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Kergoat, Kevin
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    The pH dependence of phosphate sorption and desorption in Swedish agricultural soils2012In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 189, p. 304-311Article in journal (Refereed)
    Abstract [en]

    A number of previous studies have reported the existence of a minimum in phosphate solubility between pH 5.5 and 7 in non-calcareous soils. Different hypotheses have been forwarded to explain this phenomenon. In this study, ten soil samples with varying textures and phosphorus status were subjected to batch experiments in which dissolved phosphate was measured as a function of pH and phosphate load. Soil samples with more than 20% clay all had a minimum phosphate solubility between pH 6 and 7, whereas for samples with <10% clay, no such minimum was observed. Further experiments involving additions of phosphate and arsenate showed an increasing adsorption of these anions with decreasing pH also below pH 6 in clay soils, suggesting that the pH dependence on adsorption and desorption in short-term experiments was not the same. Kinetic experiments showed that the increased phosphate desorption at lower pH values in non-calcareous clay soils was a quick process, which is consistent with adsorption/desorption being the most important mechanism governing the retention and release of inorganic P. Moreover, by comparing extraction results with batch experiment results for samples from a long-term fertility experiment, it was concluded that more than 60% of the accumulated phosphate was occluded, i.e. not reactive within 6 days. Additional evidence for an important role of occluded phosphate comes from an analysis of the Freundlich sorption isotherms for the studied soils. It is hypothesized that interlayered hydroxy-Al and hydroxy-Fe polymers in clay minerals may be important for P dynamics in clay soils by trapping some of the P in an occluded form. The results also suggest that improved knowledge on the speciation and dynamics of phosphorus in soils is required for consistent mechanistically based modeling of phosphate sorption/desorption reactions.

  • 16.
    Gustafsson, Jon Petter
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Tiberg, Charlotta
    Molybdenum binding to soil constituents in acid soils: An XAS and modelling study2015In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 417, p. 279-288Article in journal (Refereed)
    Abstract [en]

    Despite its importance as a trace element, the binding mechanisms of molybdenum in soils are not well known. In this study, we studied the binding of molybdenum onto selected soil samples, and we used X-ray absorption spectroscopy (XAS) to characterize the coordination of molybdenum on three important environmental sorbents: ferrihydrite (Fh), amorphous aluminium hydroxide (Al(OH)(3)) and fulvic acid. The X-ray near-edge structure (XANES) data showed that the added molybdenum(VI) was not reduced, although for the organic samples the coordination shifted from tetrahedral to octahedral. The EXAFS (extended X-ray absorption fine structure) analysis showed that molybdenum(VI) on Fh and Al(OH)(3) was dominated by edge-sharing bidentate complexes with Mo center dot center dot center dot Fe and Mo center dot center dot center dot Al distances of 2.80 and 2.62 angstrom, respectively. For ferrihydrite, there was a minor contribution from a corner-sharing bidentate complex at 3.55 angstrom. Further, geochemical modelling suggested an additional role of an outer-sphere complex at high pH. A sample from a spodic Bs horizon had XANES and EXAFS features similar to those of Mo sorbed to Al(OH)(3), highlighting the importance of Al(OH)(3)-type sorbents in this soil. However, in the studied organic samples molybdenum(VI) was present in a distorted octahedral configuration as an organic complex. The results were used to improve molybdenum binding reaction equilibrium constants in the CD-MUSIC model for ferrihydrite and in the Stockholm Humic Model. Collectively the results show that acid soils may contain sorbents able to bind molybdenum efficiently, and thus prevent its leaching to waters.

  • 17. He, H.
    et al.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Svensson, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Meyer, A.
    Klemedtsson, L.
    Kasimir, Å.
    Factors controlling Nitrous Oxide emission from a spruce forest ecosystem on drained organic soil, derived using the CoupModel2016In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 321, p. 46-63Article in journal (Refereed)
    Abstract [en]

    High Nitrous Oxide (N2O) emissions have been identified in hemiboreal forests in association with draining organic soils. However, the specific controlling factors that regulate the emissions remain unclear. To examine the importance of different factors affecting N2O emissions in a spruce forest on drained organic soil, a process-based model, CoupModel, was calibrated using the generalized likelihood uncertainty estimation (GLUE) method. The calibration also aims to estimate parameter density distributions, the covariance matrix of estimated parameters and the correlation between parameters and variables information, useful when applying the model on other peat soil sites and for further model improvements. The calibrated model reproduced most of the high resolution data (total net radiation, soil temperature, groundwater level, net ecosystem exchange, etc.) very well, as well as cumulative measured N2O emissions (simulated 8.7±1.1kgN2Oha-1year-1 (n=97); measured 8.7±2.7kgN2Oha-1year-1 (n=6)), but did not capture every measured peak. Parameter uncertainties were reduced after calibration, in which 16 out of 20 parameters changed from uniform distributions into normal distributions or log normal distributions. Four parameters describing bypass water flow, oxygen diffusion and soil freezing changed significantly after calibration. Inter-connections and correlations between many calibrated parameters and variables reflect the complex and interrelated nature of pedosphere, biosphere and atmosphere interactions. This also highlights the need to calibrate a number of parameters simultaneously. Model sensitivity analysis indicated that N2O emissions during growing seasons are controlled by competition between plants and microbes for nitrogen, while during the winter season snow melt periods are important. Our results also indicate that N2O is mainly produced in the capillary fringe close to the groundwater table by denitrification in the anaerobic zone. We conclude that, in afforested drained peatlands, the plants and groundwater level have important influences on soil N availability, ultimately controlling N2O emissions.

  • 18. He, Hongxing
    et al.
    Meyer, Astrid
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Svensson, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Rutting, Tobias
    Klemedtsson, Leif
    Simulating ectomycorrhiza in boreal forests: implementing ectomycorrhizal fungi model MYCOFON in CoupModel (v5)2018In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 11, no 2, p. 725-751Article in journal (Refereed)
    Abstract [en]

    The symbiosis between plants and Ectomycorrhizal fungi (ECM) is shown to considerably influence the carbon (C) and nitrogen (N) fluxes between the soil, rhizosphere, and plants in boreal forest ecosystems. However, ECM are either neglected or presented as an implicit, undynamic term in most ecosystem models, which can potentially reduce the predictive power of models. In order to investigate the necessity of an explicit consideration of ECM in ecosystem models, we implement the previously developed MYCOFON model into a detailed process-based, soil-plant-atmosphere model, Coup-MYCOFON, which explicitly describes the C and N fluxes between ECM and roots. This new Coup-MYCOFON model approach (ECM explicit) is compared with two simpler model approaches: one containing ECM implicitly as a dynamic uptake of organic N considering the plant roots to represent the ECM (ECM implicit), and the other a static N approach in which plant growth is limited to a fixed N level (nonlim). Parameter uncertainties are quantified using Bayesian calibration in which the model outputs are constrained to current forest growth and soil C / N ratio for four forest sites along a climate and N deposition gradient in Sweden and simulated over a 100-year period. The "nonlim" approach could not describe the soil C / N ratio due to large overestimation of soil N sequestration but simulate the forest growth reasonably well. The ECM "implicit" and "explicit" approaches both describe the soil C / N ratio well but slightly underestimate the forest growth. The implicit approach simulated lower litter production and soil respiration than the explicit approach. The ECM explicit Coup-MYCOFON model provides a more detailed description of internal ecosystem fluxes and feedbacks of C and N between plants, soil, and ECM. Our modeling highlights the need to incorporate ECM and organic N uptake into ecosystem models, and the nonlim approach is not recommended for future long-term soil C and N predictions. We also provide a key set of posterior fungal parameters that can be further investigated and evaluated in future ECM studies.

  • 19. Jansson, P.E
    et al.
    Karlberg, L
    Theory and practice of coupled heat and mass transfer model for soil-plant-atmosphere system2009Book (Refereed)
  • 20. Khoshkhoo, Y.
    et al.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Irannejad, P.
    Khalili, A.
    Rahimi, H.
    Calibration of an energy balance model to simulate wintertime soil temperature, soil frost depth, and snow depth for a 14year period in a highland area of Iran2015In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 119, p. 47-60Article in journal (Refereed)
    Abstract [en]

    A physically-based heat and mass transfer model, CoupModel, is calibrated to simulate wintertime soil temperature, soil frost depth, and snow depth for a 14-year period in a highland area of Iran. A Monte Carlo based approach is used for calibration process based on subjective performance criteria. Sensitivity and uncertainty analyses of the model were performed by selecting 30 parameters and the model was run using 22,000 samples taken from the uncertainty range of the parameters. By using the Nash-Sutcliffe Index to evaluate the performance of the model and applying a cutoff threshold for the performance to snow depth and soil temperature, 161 behavioral simulations were recognized and considered as the accepted ensemble to represent the field conditions. Sensitivity analysis of the model revealed some parameters associated with soil evaporation, soil hydraulic properties, and snow modeling as sensitive and highly important parameters. Uncertainty analysis of the model for wintertime soil temperatures showed a reasonable agreement between simulations and observations in most cases. However, a systematic error occurred at some periods because of high uncertainty of the actual snow density and details of snow melting. Uncertainties were also due to the simplified model assumptions regarding snow thermal properties and temperature within snow cover. The snow depth at the accumulation and melting stages were described well by the model in most cases.

  • 21.
    Larsson, Maja A.
    et al.
    Swedish Univ Agr Sci,Uppsala.
    D'Amato, Marilena
    Italian Natl Hlth Inst, Rome.
    Cubadda, Francesco
    Italian Natl Hlth Inst, Rome.
    Raggi, Andrea
    Italian Natl Hlth Inst, Rome.
    Oborn, Ingrid
    Swedish University of Agricultural Sciences, Uppsala and World Agroforestry Centre (ICRAF) Nairobi.
    Kleja, Dan Berggren
    Swedish Univ Agr Sci, Uppsala and Swedish Geotechnical Institute, Gothenburg.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Swedish Univ Agr Sci, Sweden, Uppsala.
    Long-term fate and transformations of vanadium in a pine forest soil with added converter lime2015In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 259, p. 271-278Article in journal (Refereed)
    Abstract [en]

    A field-trial with different application rates of converter lime (0.2, 0.7 and 1.0 kg m(-2)) was set up in a pine forest stand in southern Sweden in 1984. The lime contained 14.6 g kg(-1) vanadium. The aim with this study was to evaluate the vanadium concentration and speciation in the soil 26 years after application. Samples of the organic mar layer and the mineral soil were analyzed separately. The vanadium concentration decreased with soil depth, from 680 to 8 mg kg(-1) soil. Analysis by vanadium K-edge}CANES spectroscopy showed that vanadium(IV) was the predominant species in the mar layer. Further, iron and/or aluminum (hydr)oxides were important sorbents for vanadium(V) in the mineral soil. The spedation of dissolved vanadium, as determined by HPLC-ICP-MS, was dominated by vanadium(V), which is considered the most toxic vanadium species. However, the vanadium sorption capacity of the soil was sufficient to reduce the total bioavailable vanadium below phytotoxic levels. By combining two different vanadium spedation methods, this study was able to conclude that vanadium speciation in soils is governed by soil properties such as pH, organic matter content and the content of metal (hydr)oxides, but not by the vanadium species added to the soil.

  • 22. Larsson, Maja A.
    et al.
    Hadialhejazi, Golshid
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Swedish University of Agricultural Sciences, Sweden.
    Vanadium sorption by mineral soils: Development of a predictive model2017In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 168, p. 925-932Article in journal (Refereed)
    Abstract [en]

    The toxicity of vanadium in soils depends on its sorption to soil components. Here we studied the vanadate(V) sorption properties of 26 mineral soils. The data were used to optimise parameters for a Freundlich equation with a pH term. Vanadium K-edge XANES spectroscopy for three selected soils confirmed that the added vanadate(V) had accumulated mostly as adsorbed vanadate(V) on Fe and Al hydrous oxides, with only minor contributions from organically complexed vanadium(IV). Data on pH-dependent V solubility for seven soils showed that on average 0.36 H+ accompanied each V during adsorption and desorption. The resulting model provided reasonable fits to the V sorption data, with r2 &gt; 0.99 for 20 of 26 soils. The observed KdS value, i.e. the ratio of total to dissolved V, was strongly dependent on V addition and soil; it varied between 3 and 4 orders of magnitude. The model was used to calculate the Freundlich sorption strength (FSS), i.e. the amount of V sorbed at [V] = 2.5 mg L−1, in the concentration range of observed plant toxicities. A close relationship between FSS and oxalate-extractable Fe and Al was found (r2 = 0.85) when one acidic soil was removed from the regression. The FSS varied between 27 and 8718 mg V kg−1, showing that the current environmental guidelines can be both under- and overprotective for vanadium.

  • 23.
    McGivney, Eric
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Belyazid, Salim
    Stockholm Univ, Dept Phys Geog, S-10691 Stockholm, Sweden..
    Zetterberg, Therese
    IVL Swedish Environm Res Inst, POB 53021, S-40014 Gothenburg, Sweden..
    Lofgren, Stefan
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, POB 7050, S-75007 Uppsala, Sweden..
    Assessing the impact of acid rain and forest harvest intensity with the HD-MINTEQ model - soil chemistry of three Swedish conifer sites from 1880 to 20802019In: SOIL, ISSN 2199-3971, Vol. 5, no 1, p. 63-77Article in journal (Refereed)
    Abstract [en]

    Forest soils are susceptible to anthropogenic acidification. In the past, acid rain was a major contributor to soil acidification, but, now that atmospheric levels of S have dramatically declined, concern has shifted towards biomass-induced acidification, i.e. decreasing soil solution pH due to tree growth and harvesting events that permanently remove base cations (BCs) from forest stands. We use a novel dynamic model, HD-MINTEQ (Husby Dynamic MINTEQ), to investigate possible long-term impacts of two theoretical future harvesting scenarios in the year 2020, a conventional harvest (CH, which removes stems only), and a whole-tree harvest (WTH, which removes 100 % of the above-ground biomass except for stumps) on soil chemistry and weathering rates at three different Swedish forest sites (Aneboda, Gardsjon, and Kindla). Furthermore, acidification following the harvesting events is compared to the historical acidification that took place during the 20th century due to acid rain. Our results show that historical acidification due to acid rain had a larger impact on pore water chemistry and mineral weathering than tree growth and harvesting, at least if nitrification remained at a low level. However, compared to a no-harvest baseline, WTH and CH significantly impacted soil chemistry. Directly after a harvesting event (CH or WTH), the soil solution pH sharply increased for 5 to 10 years before slowly declining over the remainder of the simulation (until year 2080). WTH acidified soils slightly more than CH, but in certain soil horizons there was practically no difference by the year 2080. Even though the pH in the WTH and CH scenario decreased with time as compared to the no-harvest scenario (NH), they did not drop to the levels observed around the peak of historic acidification (1980-1990), indicating that the pH decrease due to tree growth and harvesting would be less impactful than that of historic atmospheric acidification. Weathering rates differed across locations and horizons in response to historic acidification. In general, the predicted changes in weathering rates were very small, which can be explained by the net effect of decreased pH and increased Al3+, which affected the weathering rate in opposite ways Similarly, weathering rates after the harvesting scenarios in 2020 remained largely unchanged according to the model.

  • 24.
    Merouani, Zein-Eddine
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Behaviour of anchors in sand: deterministic and probabilistic analyses2007Doctoral thesis, monograph (Other scientific)
  • 25. Mohammadi, Ali
    et al.
    Cowie, Annette
    Mai, Thi Lan Anh
    Anaya de la Rosa, Ruy
    Brandao, Miguel
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Kristiansen, Paul
    Joseph, Stephen
    Quantifying the greenhouse gas reduction benefits of utilising straw biochar and enriched biochar2016In: EUROPEAN GEOSCIENCES UNION GENERAL ASSEMBLY 2016, Elsevier, 2016, p. 254-261Conference paper (Refereed)
    Abstract [en]

    This study investigated the carbon footprint of two different biochar production systems for application to paddy fields. The impacts of using rice straw-derived biochar in raw form (System A) were compared with those arising from using rice straw biochar enriched with lime, clay, ash and manure (System B). The GHG abatement of the management of one Mg of rice straw in Systems A and B was estimated at 0.27 and 0.61 Mg CO2-eq, respectively, in spring season, and 0.30 and 1.22 Mg CO2-eq in summer. The difference is mainly due to greater reduction of soil CH4 emissions by enriched biochar.

  • 26.
    Pham Van, Quang
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. An Giang University.
    Soil Degradation of Raised-beds on Orchards in the Mekong Delta Field and Laboratory Methods2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Soil degradation is a complex process which may occur anywhere and at any time. It directly affects the physical, chemical and biological processes within the soil profile. Soil degradation can either be as a result of natural hazards or due to manmade actions, such as mismanagement on cropping patterns, soil preparation and cultivation practices. Regardless of how it is caused, soil degradation has strong negative effects on plant and soil productivity. Soil degradation can accelerate a series of processes such as erosion, compaction, loss of organic matter, loss of whole soil biota, surface sealing and contamination. This thesis presents the assessment of soil properties to improve our understanding of soil degradation on raised-bed orchards in the Vietnamese Mekong delta (MD). Measurements were made on 10 citrus plantations which had been established during a range of years from 1970 to 1998 at Hau Giang province. Soil sampling was made in the dry season of 2010 at two soil depths for each raised-bed to determine soil chemical and physical properties. The soil penetration resistance (PR) was periodically measured once a week together with soil sampling for moisture measurements during a period of 5 months. Analysis indicated the pH value of the soil was tending to decrease, nutrient imbalance and deficiency was developing, and the soil structure was deteriorating during the age since the raised-beds were originally constructed. Preventive and restorative measures need to be considered for restoring and retaining the quality of the soil and the ground water. These measures should consist of (1) neutralizing of excess acidity, (2) balancing of nutrients, (3) maintaining of soil organic matter, and (4) application of appropriate irrigation schedules.

  • 27. Shaheen, S. M.
    et al.
    Alessi, D. S.
    Tack, F. M. G.
    Ok, Y. S.
    Kim, K. -H
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Swedish University of Agricultural Sciences, Department of Soil and Environmen.
    Sparks, Donald Lewis
    Rinklebe, J.
    Redox chemistry of vanadium in soils and sediments: Interactions with colloidal materials, mobilization, speciation, and relevant environmental implications - A review2019In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 265, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Vanadium (V), although serving as an important component of industrial activities, has bioinorganic implications to pose highly toxic hazards to humans and animals. Soils and sediments throughout the world exhibit wide ranges of vanadium concentrations. Although vanadium toxicity varies between different species, it is mainly controlled by soil redox potential (E H ). Nonetheless, knowledge of the redox geochemistry of vanadium lags in comparison to what is known about other potentially toxic elements (PTEs). In particular, the redox-induced speciation and mobilization of vanadium in soils and sediments and the associated risks to the environment have not been reviewed to date. Therefore, this review aims to address 1) the content and geochemical fate of vanadium in soils and sediments, 2) its redox-induced release dynamics, 3) redox-mediated chemical reactions between vanadium and soil organic and inorganic colloidal materials in soil solution, 4) its speciation in soil solution and soil-sediments, and 5) the use of advanced geochemical and spectroscopic techniques to investigate these complex systems. Vanadium (+5) is the most mobile and toxic form of its species while being the thermodynamically stable valence state in oxic environments, while vanadium (+3) might be expected to be predominant under euxinic (anoxic and sulfidic) conditions. Vanadium can react variably in response to changing soil E H : under anoxic conditions, the mobilization of vanadium can decrease because vanadium (+5) can be reduced to relatively less soluble vanadium (+4) via inorganic reactions such as with H 2 S and organic matter and by metal-reducing microorganisms. On the other hand, dissolved concentrations of vanadium can increase at low E H in many soils to reveal a similar pattern to that of Fe, which may be due to the reductive dissolution of Fe(hydr)oxides and the release of the associated vanadium. Those differences in vanadium release dynamics might occur as a result of the direct impact of E H on vanadium speciation in soil solution and soil sediments, and/or because of the E H -dependent changes in soil pH, chemistry of (Fe)(hydr)oxides, and complexation with soil organic carbon. Release dynamics of vanadium in soils may also be affected positively by soil pH and the release of aromatic organic compounds. X-ray absorption spectroscopy (XAS) is a powerful tool to investigate the speciation of vanadium present in soil. X-ray absorption near edge structure (XANES) is often used to constrain the average valence state of vanadium in soils and sediments, and in limited cases extended X-ray absorption fine structure (EXAFS) analysis has been used to determine the average molecular coordination environment of vanadium in soil components. In conclusion, this review presents the state of the art about the redox geochemistry of vanadium and thus contributes to a better understanding of the speciation, potential mobilization, and environmental hazards of vanadium in the near-surface environment of uplands, wetlands, and agricultural ecosystems as affected by various colloidal particles. Further research is needed to elucidate the geochemistry and speciation of vanadium in the dissolved, colloidal, and soil sediments phases, including the determination of factors that control the redox geochemistry of vanadium.

  • 28.
    Wu, Mousong
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Experimental study on evaporation from seasonally frozen soils under various water, solute and groundwater conditions in Inner Mongolia, China2016In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 535, p. 46-53Article in journal (Refereed)
  • 29.
    Wu, Mousong
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Water, Heat and Solute processes in Seasonally frozen Soils: Experimental and Modeling Study2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Soil freezing and thawing is of importance in transport of water, heat and solute, which has coupled effects. Solute type and solute content in frozen soil could influence the osmotic potential of frozen soil and decrease freezing point, resulting in differences in soil freezing characteristic curves under various solute conditions. Prediction model provides an approach for estimating soil freezing characteristic curves under various water and solute conditions based on soil freezing characteristic curve obtained at certain water and solute conditions. Water, heat and solute transport in seasonally frozen soil is a coupled process strongly linked to evaporation and energy balance of soil surface. High solute content and shallow GWTD provide good conditions for water and solute accumulation in surface layer, which would result in more evaporation during thawing. Also, high solute content in upper layer would cause more liquid water to exist in upper layer, which may enhance evaporation during freezing period. Obvious increase in cumulative evaporation amount was detected for frost tube experiments, 51.0, 96.6, to 114.0 mm when initial solute content increased from 0.2%, 0.4%, to 0.6%, and initial GWTD of 1.5 m. Similar trends were observed for other GWTD and solute treatments. Water and heat transport simulated by the CoupModel combined with GLUE calibration showed good performances, when constrained by certain criteria. Uncertainties were investigated using ensemble of modeling results. Simulated energy partitioning showed intensive oscillations in daily courses during soil freezing/thawing periods and strongly influenced the stability of energy system on surface of soil. The study demonstrated the complexity in water, heat and solute transport in seasonally frozen soil, and the necessity of combining experimental data with numerical model for better understanding the processes as well in decision making for irrigation district water resources management.

  • 30.
    Wu, Mousong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Tan, X.
    Wu, J.
    Huang, J.
    Simulations of water and heat dynamics in a seasonally frozen soil using field data to improve understanding,Manuscript (preprint) (Other academic)
  • 31.
    Wu, Mousong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Wuhan University, China.
    Tan, Xiao
    Huang, Jiesheng
    Wu, Jingwei
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Solute and water effects on soil freezing characteristics based on laboratory experiments2015In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 115, p. 22-29Article in journal (Refereed)
    Abstract [en]

    Laboratory experiments were conducted to study effects of water and solute on soil freezing using TDR and temperature sensor combination methods. ANOVA methods were applied for analyzing significance for solute influences on soil freezing characteristic curve (SFCC). Results showed that higher initial water content influenced the SFCC by increasing liquid water content at the same temperature due to more water connection with soil pores, and adsorbed by soil particles. ANOVA results showed solute content and solute type all had significant effects (P < 0.001 to P < 0.5) on soil freezing processes. And solute in soil resulted in a lower freezing point of soil, which made more liquid water co-exist with ice at negative temperatures. And solute concentration condensing due to liquid water decline would also impede soil freezing processes by decreasing osmotic potential. Due to the physical and chemical process of soil solution, different ions also presented some differences in SFCC parameter estimation. Based on a trial and error method, a prediction model was also built, and it behaved well in predicting SFCC under different water and solute conditions.

  • 32.
    Wu, Mousong
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Wu, Jingwei
    Wuhan Univ, State Key Lab Water Resources & Hydropower Engn S, Wuhan 430072, Hubei, Peoples R China..
    Tan, Xiao
    Wuhan Univ, State Key Lab Water Resources & Hydropower Engn S, Wuhan 430072, Hubei, Peoples R China.;Sichuan Univ, Coll Water Resource & Hydropower, State Key Lab Hydraul & Mt River Engn, Chengdu 610065, Sichuan, Peoples R China..
    Huang, Jiesheng
    Wuhan Univ, State Key Lab Water Resources & Hydropower Engn S, Wuhan 430072, Hubei, Peoples R China..
    Jansson, Per Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Zhang, Wenxin
    Univ Copenhagen, Ctr Permafrost, Dept Geosci & Nat Resource Management, DK-1350 Copenhagen, Denmark..
    Simulation of dynamical interactions between soil freezing/thawing and salinization for improving water management in cold/arid agricultural region2019In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 338, p. 325-342Article in journal (Refereed)
    Abstract [en]

    In cold/arid agricultural regions seasonal freezing/thawing of soils can result in soil salinization in winter; therefore, it is crucial to understand the mechanisms behind soil salinization during winter for better water management in agriculture. In Hetao Irrigation District of Inner Mongolia, northern China, we used the CoupModel (version 5) considering dynamical impacts of salt on soil freezing point to simulate soil salt dynamics and soil freezing/thawing in three winters during 2012-2015. The simulated soil temperature at different depths was improved by 10% with respect to the Nash-Sutcliffe coefficient NSE R-2 when dynamical salt impact on freezing point was taken into accounted. Simulations revealed that ice coverage on soil surface as well as water stored in drainage ditches during winter cause more severe salinization in spring due to improper Al (Autumn Irrigation) practices combining poor drainage systems. A new Al practice with earlier irrigation date (i.e. 10 d earlier than 2012/2013 winter regulation), longer irrigation period (i.e. 7 d instead of 3 d), but with less irrigation water (reduced by 20% from 2012/2013 winter regulation) was then proposed. The new AI practice can control groundwater level and salt accumulation better during winters, Our results highlight the importance of combining detailed field irrigation tests with a process-based model accounting for interactions between soil freezing/thawing and salinization to improve water management efficiency in cold/arid agricultural regions.

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