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1.
  • Danielsson, Katarina, et al. (författare)
  • Dim light melatonin onset in normal adults and its relationship with sleep timing and diurnal preference
  • 2012
  • Ingår i: Biological rhythm research. - : Informa UK Limited. - 0929-1016 .- 1744-4179. ; 43:5, s. 497-503
  • Tidskriftsartikel (refereegranskat)abstract
    • Dim light melatonin onset (DLMO) is defined as the start of the melatonin production in the evening during dim light conditions and has become a reliable phase marker of the circadian clock. The aim of the study was to investigate DLMO and its association with sleep timing and diurnal preferences in healthy working adults during real-life conditions. Fourteen adults were investigated. A sleep diary was kept during the preceding week, but no fixed sleep–wake schedule was implemented. Diurnal preferences were measured with the Horne–O¨ stberg Morningness–Eveningness Questionnaire. DLMO was defined as the time point when melatonin in saliva exceeded a threshold of 3 ng/L. Results showed that DLMO appeared in the expected time interval but was not significantly associated with sleep timing or diurnal preference. The results illustrate the complexity of monitoring sleep patterns in real-life settings.
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3.
  • Andersen, Christian B., et al. (författare)
  • Pythium oligandrum induces growth promotion in starch potato without significantly altering the rhizosphere microbiome
  • 2024
  • Ingår i: Applied Soil Ecology. - 0929-1393 .- 1873-0272. ; 199
  • Tidskriftsartikel (refereegranskat)abstract
    • Plant health promoting organisms, including microbial biological control agents, are of increasing importance for the development of more sustainable agriculture. To understand the function of these microbes as biological control agents under field conditions and their overall impact on soil and plant health, we need to learn more about the impact of plant beneficial microbes on the rhizosphere microbiome of crops such as potato. The plant beneficial oomycete Pythium oligandrum has previously been reported both as a biocontrol agent and as a plant growth promoter, or biostimulant, in several crop species. To investigate the potential of P. oligandrum as a biostimulant in potato, we performed a series of controlled-environment bioassays in three cultivars. We showed that biostimulation of potato by P. oligandrum is plant genotype-specific. We confirmed the biostimulation by P. oligandrum in the starch potato cultivar Kuras under field conditions. We further investigated the effects of P. oligandrum on the potato rhizosphere microbiome, sampling individual potato plants at three time points over the growing season (representing the vegetative growth phase, flowering, and the onset of senescence). Metabarcoding using ITS and 16S amplicon sequencing revealed no significant overall effect of P. oligandrum application on the bacterial and fungal rhizosphere communities. However, some genera were significantly differentially abundant after P. oligandrum application, including some classified as plant-beneficial microbes. We conclude that P. oligandrum has a cultivar-dependent growth-promoting effect in potato and only minor effects on the rhizosphere microbiome.
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4.
  • Hydbom, Sofia, et al. (författare)
  • Biochemical signatures reveal positive effects of conservation tillage on arbuscular mycorrhizal fungi but not on saprotrophic fungi and bacteria
  • 2021
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 157
  • Tidskriftsartikel (refereegranskat)abstract
    • Since tillage can reduce the amount of organic C stored in soils, the use of conservation tillage practices, which exclude soil inversion, or include it less frequently, is often promoted. Soil microorganisms are closely linked to soil organic C (SOC), and they are assumed to respond quicker to management changes than SOC. Using two Swedish long-term tillage experiments, our aim was to determine whether (i) continuous conservation tillage (harrowing, H) increase microbial biomass (indicated by fatty acid signatures) compared to plowing (P), and if occasionally tilled soil (HP) was more like H or P. Also, the aim was to determine whether (ii) crop residue management has different effects on microbial biomass depending on tillage management, and whether (iii) conservation tillage and residue return increase SOC. We found that arbuscular mycorrhizal fungi (AMF) were stimulated by the H treatment compared to P treatment in the upper soil layer, and that occasional plowing resulted in intermediate amounts of AMF. The amount of microbial saprotrophs, on the other hand, was not affected by tillage treatment, and neither was the SOC concentration. Whether crop residues were returned in the autumn or not, had no direct effect on the microbial saprotrophs or the SOC after the winter, but crop residue removal stimulated AMF close to the surface in the P treatment. Although more research is needed to fully understand agricultural tillage and residue management effects on SOC dynamic, our study suggests that reducing or omitting plowing influence soil microbes, but does not necessarily result in more SOC.
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5.
  • Kozjek, Katja, et al. (författare)
  • Long-term agricultural management impacts arbuscular mycorrhizal fungi more than short-term experimental drought
  • 2021
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 168
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural management practices and extreme weather events associated with climate change can influence the diversity and abundance of arbuscular mycorrhizal fungi (AMF) with potential consequences for crop production. However, the importance of the interactive effects of long-term agricultural management and extreme weather events on AMF communities in agricultural soils is not yet fully explored. A short-term drought experiment with rainout-shelters was performed in winter wheat fields in a long-term agricultural trial with organic (biodynamic) and conventional management practices. During four months of the winter wheat growing period (March–June 2017), the rainout-shelters reduced the ambient precipitation by 65% on average. At two sampling dates, the AMF diversity and community composition were assessed using a single-molecule real-time (SMRT) DNA sequencing. A total of 955 amplicon sequence variants (ASVs), belonging to twelve genera were identified. The long-term farming systems and the short-term experimental drought did not affect AMF ASV diversity levels. The AMF community composition at the genus level differed between the organic and the conventional farming systems, but no distinctive communities were found in response to the experimental drought. The three most abundant genera Acaulospora, Paraglomus and Funneliformis were correlated to the two farming practices. Our study demonstrates that AMF communities in agricultural soils are responsive to long-term farming systems, and are resistant to one short-term summer drought event.
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6.
  • Liu, Qiong, et al. (författare)
  • Vertical and horizontal shifts in the microbial community structure of paddy soil under long-term fertilization regimes
  • 2022
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 169
  • Tidskriftsartikel (refereegranskat)abstract
    • Knowledge remains limited on how the structure of microbial community in paddy soils changes in relation to different types of fertilizers with same amount of nutrients. Thus, here, soil samples were collected at 0–10, 10–20, 20–30, and 30–40 cm depths from a paddy field subjected to four long-term fertilization treatments (no fertilization, mineral fertilization, mineral fertilization combined with rice straw, and chicken manure) and analyzed for microbial biomass and community composition. In unfertilized soils, microbial biomass decreased from 0 to 40 cm (with actinomycetes < gram-positive (G+) bacteria < gram-negative (G? ) bacteria < fungi). This ordering was retained after fertilization, but the decline with depth was less pronounced. Both mineral and mineral plus organic fertilization increased the biomass of G+ bacteria compared to G? bacteria (22.7–56.2% increase) and actinomycetes (14.8–52.5% increase). Thus, over the long term, G+ bacteria benefited the most from mineral fertilizer than the other microbial groups. The partial replacement of mineral fertilizer with manure primarily enhanced the abundance of G+ bacteria at 0–30 cm soil depth, whereas replacement with straw enhanced the abundance of fungi at 10–20 cm soil depth. Our findings demonstrate that the structure of the microbial community is strongly impacted by long-term fertilization, independent of fertilizer type.
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7.
  • Maillard, François, et al. (författare)
  • A cryptically diverse microbial community drives organic matter decomposition in forests
  • 2024
  • Ingår i: Applied Soil Ecology. - 0929-1393. ; 193
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite the critical role of microorganisms in plant and fungal residue decomposition, our understanding of their full diversity remains limited. This is due largely to the rapid microbial succession during decomposition, a scarcity of studies including multiple sampling times, and the omission of a species richness index encompassing all decay stages. To address these gaps, we conducted a meta-analysis of 12 studies, each examining bacterial and fungal communities at multiple time points during decomposition. We aimed to determine the overall microbial diversity involved in decomposition processes by aggregating microbial richness at different time points. By comparing cumulative microbial OTU (operational taxonomic unit) richness with single time point microbial richness, we show that the cumulative richness was 2–5 times greater, indicating that a high yet frequently overlooked diversity of microorganisms is involved in the decomposition process. This pattern was consistent across different organic matter types (plant and fungal residues) for both major microbial domains (bacteria and fungi). Moreover, the appearance rate of novel OTUs generally decreased over time for most organic matter types, except for dead wood, which accumulated new fungal OTUs at a notable pace. Our results collectively emphasize the importance of considering various microbial domains, organic matter types, and time points to successfully characterize the diversity of microorganisms involved in decomposition. Further, given the hidden cumulative number of bacterial and fungal species held within plant and fungal residues across decay stages, we propose that these substrates are crucial microbial reservoirs to include to accurately assess global terrestrial microbial diversity.
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8.
  • Mollah, Sabur, et al. (författare)
  • Heterogeneity in independent non-executive directors' attributes and risk-taking in large banks
  • 2021
  • Ingår i: Journal of Corporate Finance. - : Elsevier BV. - 0929-1199. ; 70
  • Tidskriftsartikel (refereegranskat)abstract
    • The extant literature suggests that complex firms can benefit from independent non-executive director (INED) quality. To address the issue of INED quality, we look at heterogeneity in the independent non-executive directors' (INEDs') attributes and explore whether this is related to risk-taking behaviour in large banks. We gather novel, hand-collected, director-level data for approximately 2400 independent non-executive directors (INEDs) of 185 global large banks from 35 countries for the period of 2004–2016, concluding that heterogeneity in INEDs' gender, financial expertise, and board tenure all influence risk-taking behaviour. Employing several identification strategies, we show that the cause seems to be heterogeneity in the INEDs' attributes, as channelled through information asymmetry. We also find that heterogeneity in the INEDs' attributes significantly mitigates bank risk-taking in the post-2009 period. Our study contributes to the literature on both the benefits of INEDs and director heterogeneity.
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9.
  • Zhu, Zhenke, et al. (författare)
  • Microorganisms maintain C:N stoichiometric balance by regulating the priming effect in long-term fertilized soils
  • 2021
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 167
  • Tidskriftsartikel (refereegranskat)abstract
    • Labile carbon (C) inputs affect the soil carbon:nitrogen (C:N) ratio and microbial stoichiometric homeostasis, which control the intensity and direction of the priming effect (PE). Here, we clarified how soil microorganisms regulate enzyme production and PE to maintain the C:N stoichiometric balance. Specifically, we conducted an incubation experiment by adding 13C-labeled glucose to four long-term fertilized paddy soils: no fertilization; fertilization with mineral nitrogen, phosphorus, and potassium (NPK); NPK combined with straw; and NPK with manure (NPKM). After glucose addition, the dissolved organic carbon-to-ammonium (DOC:NH4+) ratio (24–39) initially increased, but subsequently decreased after day 2 following glucose exhaustion. In parallel, the microbial C:N imbalance [(DOC:NH4+):(microbial biomass C:microbial biomass N)] rapidly decreased from day 2 (4.6–7.2) to day 20 (<0.5). Thus, microorganisms became C limited after 20 days of incubation. Excess C, resulting from glucose addition, increased N-hydrolase (chitinase) production and N mining from soil organic matter (SOM) through positive PEs. However, C hydrolase (β-1,4-glucosidase and β-xylosidase) activity increased, while that of N hydrolase (chitinase) decreased, following glucose exhaustion. Consequently, the C:N microbial biomass ratio increased as the DOC:NH4+ ratio decreased, leading to negative PEs. NPKM-fertilized soil had the largest cumulative PE (2.3% of soil organic carbon) because it had the highest microbial biomass and iron (Fe) reduction rate. Thus, this increased N mining from SOM maintained the microbial C:N stoichiometric balance. We concluded that soil microorganisms regulate C- and N-hydrolase production to control the intensity and direction of PE, maintaining the C:N stoichiometric balance in response to labile C inputs.
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10.
  • Albizua, Amaia, et al. (författare)
  • Crop rotations including ley and manure can promote ecosystem services in conventional farming systems
  • 2015
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 95, s. 54-61
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural intensification has contributed substantially to the increase in food production, but has come at the expense of soil degradation and environmental problems. Management of soil based ecosystem services need to be considered in agricultural management since intensive management implies not only costs to the farmer but also to society. In this study we used data from four long-term (55 years) agricultural experiments in southern Sweden to assess the effects of two arable farming systems on a range of indicators of soil ecosystem services. One farming system used only annual commodity crops (ACC system) while the other integrated one year of ley (ley system) into the crop rotation. Nitrogen (N) fertiliser was applied annually in both farming systems at two rates (0 and 150 kg N ha(-1)). The ley farming system had an addition of farmyard manure (FYM) once every fourth year. Soil organic carbon, total N, phosphorous, potassium, pH and water holding capacity were used as indicators of regulating services; bacterial and fungal biomass were used as indicators of supporting services; grain yield and protein content were used as indicators of provisioning services. We analysed each of the indicators separately, to identify effects of the farming systems, using linear mixed effects models. In addition, we used principal components analysis to bundle the individual indicators together to create latent variables representing categories of ecosystem services. Yields of wheat were greatest in the plots that received N fertiliser, irrespective of farming system, while mycorrhizal fungal biomass was greatest in the ley system with no inorganic N fertiliser. The rest of the indicators were similar in both farming systems although the lowest values of all ecosystem service indicators were found in the ACC system with no N fertiliser. When bundling the indicators, no trade-offs were found between regulating, supporting and provisioning services. Regulating and supporting services were positively correlated, as were regulating and provisioning services. The ley system with N fertiliser had significantly greater values of regulating and provisioning services relative to the other treatments. The results indicate that different farming systems can have large effects on ecosystem service flows, and that integrating leys into arable rotations can enhance the delivery of soil ecosystem services. (C) 2015 Elsevier B.V. All rights reserved.
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11.
  • Aldén, Louise, et al. (författare)
  • The use of leucine incorporation to determine the toxicity of phenols to bacterial communities extracted from soil
  • 2008
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 38:1, s. 34-41
  • Tidskriftsartikel (refereegranskat)abstract
    • The toxicity of different phenols to the soil bacterial community was studied in the laboratory using the leucine incorporation technique. The effects of environmental factors such as pH, temperature and binding strength to soil particles were also assessed in order to deduce confounding effects due to the chemical and physical conditions in the soil from which the bacterial community was extracted. Bacterial growth varied with temperature and pH, the optima being at around 33 degrees C and pH 7 in a soil with a natural pH of 7. The toxicity of different phenols varied less than bacterial growth as a function of temperature and pH, but the toxicity of 2,3,6-trichlorophenol increased at lower temperatures and pH. The pH affected the toxicity in the same way in soils with naturally different pH values and when the pH was changed using buffers, showing that this was a direct effect of pH and was not due to different communities in different soils. The degree to which the bacteria were bound to soil particles had no effect on the toxicity of phenols. Neither did freezing nor thawing the soil have any effect on toxicity, although the bacterial growth was lower in frozen soil than in non-frozen soil. Increasing numbers of substitutes on the phenols increased their toxicity to soil bacteria, and chlorine substitutes were more toxic than the corresponding methyl substitutes. The toxicity of the phenols studied to the whole soil bacterial community was correlated with literature data on the toxicity to the single species Pseudomonas putida. Applying the leucine incorporation technique to the bacterial community extracted from soil was shown to be a rapid and sensitive method of estimating toxicity. The methodology also allowed differentiation between the effects of environmental factors on toxicity to the soil bacterial community and changes in the tolerance of the community. Thus, the development of pollution-induced community tolerance in phenol- and 2-chlorophenol-polluted soils could be shown. (c) 2007 Elsevier B.V. All rights reserved.
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12.
  • Aleklett, Kristin, et al. (författare)
  • Effects of organic amendments with various nitrogen levels on arbuscular mycorrhizal fungal growth
  • 2012
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 60, s. 71-76
  • Tidskriftsartikel (refereegranskat)abstract
    • Arbuscular mycorrhizal fungi (AMF) are plant symbionts capable of enhancing nutrient uptake and improving soil structure. These features have brought AMF into focus as a component of soil restoration practices in ecosystems with degraded or highly eroded soils. It has been suggested that increasing the levels of organic material in the soil will enhance the production of AMF biomass, and that organic amendments with high concentrations of nitrogen (N) generate the largest increases in AMF growth. We tested the effects of different organic amendments and N sources on AMF responses in a natural sand dune system and pot cultures of Zea Mays L. The in-growth of AMF was measured as relative biomass through analyses of signature phospholipid fatty acids (PLFA) and neutral lipid fatty acids (NLFA) from mesh bags with different treatments. In the field, results showed a significant positive effect in AMF growth from adding a naturally N-rich organic amendment (alfalfa). Amendments of the low-N organic amendment (barley straw) produced no positive effect, and the effect was negative when ammonium nitrate (NH4NO3) was added to the barley straw to simulate the N concentrations of alfalfa. Saprophytic fungi, on the other hand, were stimulated by additions of NH4NO3. In greenhouse conditions, alfalfa and yeast extract were found to have a similar effect on AMF growth when added proportionally to their N content, even though their mass and texture are distinct. These results suggest the N content in organic amendments does play a role in its effect on AMF growth. There are also indications that the organic or inorganic nature of the N could determine its effect on AMF growth, possibly through interactions with the surrounding microbial community. This aspect requires further investigation. (C) 2012 Elsevier B.V. All rights reserved.
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13.
  • Andresen, Louise C., et al. (författare)
  • Seasonal changes in nitrogen availability, and root and microbial uptake of (15)N(13)C(9)-phenylalanine and (15)N-ammonium in situ at a temperate heath
  • 2011
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 51, s. 94-101
  • Tidskriftsartikel (refereegranskat)abstract
    • In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free amino acid, inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-(15)N and phenylalanine-(15)N/(13)C(9). Plants preferred ammonium over phenylalanine, while microbes had no preference. Soil microbes had a 77% uptake of intact phenylalanine. Phenylalanine was acquired intact by both grasses and Calluna, with 63% and 38% uptake of intact phenylalanine in grass fine roots and Calluna roots, respectively. Inorganic N and amino acid concentrations were lowest in the period with highest plant activity and grass root biomass but were unaffected by TA addition. (C) 2011 Elsevier B.V. All rights reserved.
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14.
  • Bracht Jørgensen, Helene, et al. (författare)
  • Life-history traits of soil collembolans in relation to food quality
  • 2008
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 38:2, s. 146-151
  • Tidskriftsartikel (refereegranskat)abstract
    • Preference studies of many different collembolan species have categorised collembolans being selective in their food choice. To clarify whether collembolan food selectivity is related to fitness parameters, three species, Folsomia fimetaria, Protaphorura armata and Heteromurus nitidus, were fed three fungal species, Alternaria infectoria, Mucor hiemalis and Penicillium hordei, representing fungi of high, medium and low preference. The fungal diets were grown on soil and collembolan growth, survival and fecundity were measured. The fungus A. infectoria supported growth, survival and reproduction best in all three species of collembolans, while the fungus P. hordei was of low food quality. M. hiemalis was of medium quality and F. fimetaria was the only collembolan reproducing on M. hiemalis. F. fimetaria favoured reproduction over growth when confined to M. hiemalis. When P. armata was fed M. hiemalis it reached a size where reproduction normally starts, but no young were produced. This suggests that M. hiemalis lacks nutrients necessary for reproduction. H. nitidus did not perform well on any of the fungi offered, which were generally of low food quality for this species. In this study, where the fungal growth substrate is soil, there is a clear relationship between collembolan fitness and their food choice in contrast to some other studies where substrates optimised for fungal growth had been used. We show that specific fungal species are important for resource allocation to growth or reproduction and closely connected with food choice. Further, we argue that natural fungal growth substrates, such as soil, should be used in experiments of this kind.
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15.
  • Ek, Hans, et al. (författare)
  • Extramatrical mycelial growth, biomass allocation and nitrogen uptake in ectomycorrhizal systems in response to collembolan grazing
  • 1994
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 1:2, s. 155-169
  • Tidskriftsartikel (refereegranskat)abstract
    • The effects of Collembola grazing activities on the ectomycorrhizal symbiosis were studied in laboratory microcosms. Pinus contorta seedlings in association with Paxillus involutus were grown in a sandy soil and the Collembola Onychiurus armatus was added in different densities. To study effects on nutrient uptake by the extramatrical mycorrhizal mycelium, cups containing 15NH4+ and phytin amended soil were evenly distributed in the microcosms. These cups were covered with a net that allowed the mycelium to penetrate but neither Collembola nor plant roots. Extramatrical hyphal growth was impeded at a high density of O. Armatus. Low densities of O. armatus increased the extramatrical hyphal growth, the colonization rate of side plants and the biomass of P. involutus. However, the amount of P. involutus on/in the plant roots was not affected. Thus, low densities of collembolans induced a shift towards a larger proportion of P. involutus growing extramatrically. The presence of O. armatus in low numbers enhanced the uptake and transfer of 15N by P. involvus to the plants by up to 76%. The Collembola population growth was not higher in mycorrhizal compared with non-mycorrhizal microcosms while nematode population size was reduced in mycorrhizal compared with non-mycorrhizal microcosms.
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16.
  • Elfstrand, S, et al. (författare)
  • Soil enzyme activities, microbial community composition and function after 47 years of continuous green manuring
  • 2007
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 35:3, s. 610-621
  • Tidskriftsartikel (refereegranskat)abstract
    • Green manuring practices can influence soil microbial community composition and function and there is a need to investigate the influence compared with other types of organic amendment. This study reports long-term effects of green manure amendments on soil microbial properties, based on a field experiment started in 1956. In the experiment, various organic amendments, including green manure, have been applied at a rate of 4 t C ha(-1) every second year. Phospholipid fatty acid analysis (PLFA) indicated that the biomass of bacteria, fungi and total microbial biomass, but not arbuscular mycorrhizal (AM) fungi, generally increased due to green manuring compared with soils receiving no organic amendments. Some differences in abundance of different microbial groups were also found compared with other organic amendments (farmyard manure and sawdust) such as a higher fungal biomass and consequently a higher fungal/bacterial ratio compared with amendment with farmyard manure. The microbial community composition (PLFA profile) in the green manure treatment differed from the other treatments, but there was no effect on microbial substrate-utilization potential, determined using the Biolog EcoPlate. Protease and arylsulphatase activities in the green manure treatment were comparable to a mineral fertilized treatment receiving no additional C, whereas acid phosphatase activity increased. It can be concluded that green manuring had a beneficial impact on soil microbial properties, but differed in some aspects to other organic amendments which might be attributed to differences in quality of the amendments.
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17.
  • Fernández-Calviño, David, et al. (författare)
  • Ecotoxicological assessment of propiconazole using soil bacterial and fungal growth assays
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 115, s. 27-30
  • Tidskriftsartikel (refereegranskat)abstract
    • Effects of the fungicide propiconazole on soil microorganisms were tested using [3H] leucine incorporation and [14C] acetate in ergosterol incorporation to measure bacterial and fungal growth inhibition, respectively. Growth was compared to basal respiration (BR) and substrate-induced respiration (SIR) in soil microcosms established according to the OECD 217 guideline. Fungal growth was most sensitive with IC50 values remaining around 300 mg kg−1 during 40 days of incubation. SIR was initially less sensitive (IC50 1300 mg kg−1), but IC50 values progressively decreased over time to reach 380 mg kg−1 after 40 days. Bacterial growth was affected at concentrations ≥200 mg kg−1, but exhibited more complex dose-response relationships possibly due to a combination of direct toxicity, bacterial community adaptation, and competitive release from the more severely affected fungi. BR was either stimulated or not affected by propiconazole. Our results indicate that group-specific endpoints targeting microbial growth will improve ecotoxicological assessment of toxicants for environmental risk assessment.
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18.
  • Fernandez-Calvino, D., et al. (författare)
  • Microbial community structure of vineyard soils with different pH and copper content
  • 2010
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 46:2, s. 276-282
  • Tidskriftsartikel (refereegranskat)abstract
    • The phospholipid fatty acid (PLFA) pattern of vineyard soils from the Northwest of the Iberian Peninsula was studied to identify soil factors determining the microbial community structure, with special emphasis on effects of Cu pollution and pH. A wide range of soil samples, collected from six winegrowing regions (Rias Baixas, Ribeiro, Ribeira Sacra, Monterrei, Valdeorras and Vinhos Verdes) was analyzed. Physicochemical properties, including total Cu content, five different Cu fractions and available Cu, were also determined. Total Cu varied between 33 and 1120 mg kg(-1) and pH(water) between 4.3 and 7.3. Soil pH rather than Cu content was most important in determining the composition of the microbial community. An increase in the relative concentrations of the monounsaturated PLFAs 16:1 omega 5, 16:1 omega 7c, 17:1 omega 8 and 18:1 omega 7 and a decrease of br18:0. i17:0, 17:0 and cy19:0 was correlated to an increase in pH. A significant effect of Cu was also found, with an increase in the branched fatty acids 10Me17:0, i16:0, 10Me18:0, a17:0 and br17:0 as consequence of Cu pollution. This change in the PLFA pattern was correlated to both the total and available fractions of Cu. Although the PLFA pattern was a useful tool to assess factors affecting the microbial composition, it is difficult to differentiate between these factors. (C) 2010 Elsevier B.V. All rights reserved.
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19.
  • Fernández-Calviño, David, et al. (författare)
  • Using pine bark and mussel shell amendments to reclaim microbial functions in a Cu polluted acid mine soil
  • 2018
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 127, s. 102-111
  • Tidskriftsartikel (refereegranskat)abstract
    • An extremely acid mine soil polluted with Cu was amended with pine bark, crushed mussel shell or a 1:1 mixture of these two by-products. The performance of the soil microbial community was measured as the bacterial and fungal community growth, which were monitored during 2 years following the amendments. Pine bark caused significant increases of microbial growth rates, but with distinct differences between fungal and bacterial groups. Bacterial growth increased transiently at intermediate rates of pine bark applications, but returned to control rates within 2 years of application. In contrast, pine bark applications consistently increased fungal growth with effects that were maintained throughout the study period. The addition of only crushed mussel shell to the mine soil caused very delayed positive effects on the bacterial growth and almost no significant effects on the fungal growth. However, the combination of pine bark with crushed mussel shells 1:1 mixtures caused positive growth responses of both bacteria and fungi that remained persistent throughout the 2 years of study. Fungal and bacterial growth were both suppressed in the mine soil by the lack of organic matter. In addition, bacterial growth was also secondarily suppressed by acidity, and hence, when organic matter (pine bark) additions were combined with pH increases (crushed mussel shell additions), bacterial growth was additionally stimulated. In conclusion, the proposed mixture of by-products (pine bark and crushed mussel shell) is suggested as a promising reclamation strategy for acid mine soils. These results also suggest that in soils like that studied here the organic matter limitation is a more important factor than the soil pH and Cu availability for fungal and bacterial performance.
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20.
  • Gavito, Mayra, et al. (författare)
  • Foraging strategies of the external mycelium of the arbuscular mycorrhizal fungi Glomus intraradices and Scutellospora calospora
  • 2008
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 39:3, s. 282-290
  • Tidskriftsartikel (refereegranskat)abstract
    • The responsiveness of the external mycelium of Glomus intraradices and Scutellospora calospora was tested in a multiple-choice experimental system in which mycelium encountered patches amended with nitrogen (N) or phosphorus (P), either alone or in combination with a host plant. We hypothesised that only AMF mycelium with sufficient supply of photo-synthate from an actively growing host would respond to the amendments provided. Mycelium was allowed to grow either 11 or 21 weeks before we analysed hyphal proliferation in amended patches introduced in mesh bags that were not reached by roots but by foraging mycelium only. Hyphal length, the AMF signature fatty acid 16:1w5, and root colonisation in new host plant seedlings were used to measure AMF growth and resource allocation in the patches. Mycelium from both fungal strains was able to colonise new host roots and sand in all patches but S. calospora was overall more responsive to the amendments than G. intraradices. G. intraradices grew equally into all patches, including the unamended control, whereas S. calospora produced significantly more hyphal length in the patch containing a host plant than in the rest of the patches. Both strains showed lower hyphal growth at the second harvest and mycelium of G. intraradices lost almost entirely its capacity to develop new mycelium in all choices presented. Lipid measurements showed this fungus did not use storage lipids to exploit the patches. S. calospora mycelium had reduced growth and colonisation ability but still showed some growth in the patches at the second harvest. A reduction in the content of NLFA 16:1w5 from the first to the second harvest suggested that S. calospora mycelium likely used storage lipids to sustain proliferation in the patches. The results indicated that S. calospora was more active and used more resources for foraging than G. intraradices; and that external mycelium foraging was maintained mainly with recently acquired plant carbon (C). This supported in general our hypothesis but showed as well that the two AMF strains had different strategies and resource allocation to forage. The overall low response of both AMF to the choices presented suggested that the responsiveness of mycelium searching freely in the substrate is lower than that observed in experimental systems in which the amendments have been placed in close contact with actively growing mycelium fronts in close vicinity with host roots.
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21.
  • Gormsen, Dagmar, et al. (författare)
  • Diversity of soil mite communities when managing plant communities on set-aside arable land
  • 2006
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 31:1-2, s. 147-158
  • Tidskriftsartikel (refereegranskat)abstract
    • When restoring former agricultural land to more low-nutrient input ecosystems, the establishment of a plant community can be enhanced by sowing desirable species. In this study our aim was to determine whether management of the plant community influences the microarthropod community. We carried out a field experiment in three European countries on set-aside arable land and determined soil mites from the sites in Sweden, The Netherlands and Spain. Experimental plots on set-aside arable land were sown with high (15 species) or low (4 species) plant species seed mixtures; other plots were colonized naturally. A field with continued agricultural practices and a later successional site (target site) were used for comparison with the experimental plots. Soil from the later successional site was inoculated into half of the plots. Abandoning agricultural practices increased the density of mites at one site while the number of mite species was not affected. Sowing plant seeds had no effect on mite densities at any of the sites. The community composition of mites changed in response to management of the plant community, as shown by canonical correspondence analysis. Among the functional groups of mites, saprophytes generally dominated on all plots at all sites. Mites parasitic on insects were not present on fields with continued agricultural practice in Sweden and The Netherlands, and might thus be regarded as an indicator of an increase in trophic complexity in the sown and naturally colonized treatments. Predatory and plant parasitic mites showed no consistent pattern in relation to the treatments of the three sites. Soil inoculation treatment had only a minor impact on the soil mite communities.
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22.
  • Gormsen, Dagmar, et al. (författare)
  • The influence of collembolans and earthworms on AM fungal mycelium
  • 2004
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 27:3, s. 211-220
  • Tidskriftsartikel (refereegranskat)abstract
    • Arbuscular mycorrhizal (AM) mycelia are dependent on contact with plant roots for spore formation. In this study, earthworms and collembolans were regarded as potential dispersal vectors of AM fungal spores and hyphae, and we determined how they influenced the extension of AM fungi from host plant roots. Plantago lanceolata seedlings were grown in a mesh bag with an AM inoculurn of dried soil and root pieces from a set-aside agricultural field. The bag was placed in a growth box that was filled with a mixture of irradiated soil and sand, into which fungal hyphae could grow while roots were retained by the mesh. Three treatments with 15 replicates each were established with an addition of either Lumbricus rubellus, Folsomia candida or no soil fauna into the root-free soil. Five replicates of each treatment were harvested after 6, 10 and 15 weeks. The extension of the AM fungi was determined by measuring PLFA 16:1w5 and NLFA 16:1w5 as signature compounds of AM fungal biomass, spore production and mycorrhizal inoculum potential on P lanceolata seedlings. After 10 weeks, all indicators of AM fungal growth showed that the fungi had extended into the whole growth box. Plant shoot biomass of the host plants was greater in the presence of earthworms than other treatments, and the contents of PLFA 16:1w5 were greater in the earthworm than in the collembolan treatment. The reduced amount of PLFA 18:2w6,9 in the collembolan treatment relative to other treatments suggests that saprophytic fungi provided a food source for the collembolans. Spore production and mycorrhizal inoculurn potential were not affected by the presence of soil fauna. We conclude that the biomass of AM fungi was stimulated by earthworms, but that fungal dispersal over 20 cm was not influenced. (C) 2004 Elsevier B.V. All rights reserved.
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23.
  • Grosso, F., et al. (författare)
  • Bacterial and fungal growth on different plant litter in Mediterranean soils : Effects of C/N ratio and soil pH
  • 2016
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 108, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Plant litter represents an important source of nutrients and energy for soil microorganisms, but will also selectively affect which organism group, fungi or bacteria, that will be favoured during decomposition. The balance of fungal to bacterial growth will furthermore be affected by soil chemistry like pH. A laboratory experiment was carried out using two different Mediterranean forest soils differing in pH, adding five types of litter varying in C/N ratio from 15 to 75, including the major litter type from the two soils. Growth of bacteria (using the leucine incorporation technique) and fungi (using the acetate into ergosterol incorporation technique) was then followed during 6 weeks. The balance of fungal to bacterial growth was positively affected by litter with increasing C/N ratio, while the C availability, as judged by evolved CO2, did not have any influence. Furthermore, low pH in the soil further favoured fungal growth, irrespective of the litter type. Despite differences in fungal to bacterial growth this appeared to have little influence on respiration rates from the added litter, suggesting functional redundancy. Our results highlight how both initial soil conditions (pH) and litter composition (C/N ratio) independently affects fungal and bacterial growth during decomposition.
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24.
  • Gustavsson, Lena, et al. (författare)
  • Regulation of phospholipase D activity in neuroblastoma cells
  • 1996
  • Ingår i: Journal of Lipid Mediators and Cell Signalling. - : Elsevier BV. - 0929-7855. ; 14:1-3, s. 229-235
  • Tidskriftsartikel (refereegranskat)abstract
    • The regulation of phospholipase D was studied in human neuroblastoma cells using phosphatidylethanol as a marker of the enzyme activity. Carbachol induced phospholipase D activity in SH-SY5Y cells. Muscarinic antagonists inhibited the response with potencies suggesting that muscarinic M1 receptors are responsible for the activation. In permeabilized SH-SY5Y cells, both the carbachol- and GTP gamma S-induced Peth formation was inhibited by GDP beta S, indicating that both responses are mediated via a G-protein. The protein kinase C inhibitors, bisindolylmaleimide and staurosporine significantly inhibited the carbachol-induced Peth formation whereas H7 had no effect. Thus, the cholinergic activation of phospholipase D in SH-SY5Y cells is probably mediated via a direct receptor-G-protein coupling but an involvement of protein kinase C cannot be excluded. Calmidazolium, a calmodulin antagonist, induced an increase in phosphatidylethanol formation in both SH-SY5Y and IMR-32 cells. This effect was inhibited by genistein and tyrphostin, indicating a tyrosine kinase dependent pathway for phospholipase D activation in neuroblastoma cells.
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25.
  • Hammer, Edith, et al. (författare)
  • Biochar increases arbuscular mycorrhizal plant growth enhancement and ameliorates salinity stress
  • 2015
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 96, s. 114-121
  • Tidskriftsartikel (refereegranskat)abstract
    • We examined combined effects of biochar, arbuscular mycorrhizal (AM) fungi and salinity on plant growth and physiology to test whether and how biochar influences AM fungi mediated growth and nutrition enhancements, and whether and how biochar provides amelioration in salt stressed soils. We carried out a full three-factorial greenhouse experiment with Lactuca sativa; and a second study with a wider range of biochar and salt additions to examine physicochemical effects on soil parameters. Biochar together with AM fungal inoculation resulted in an additional plant yield increase compared to each alone under non-saline conditions. In parallel with increased plant growth, we found increased uptake of P and Mn with AM fungi and biochar addition, but to a lesser extent than biochar-induced growth promotion. Both factors, but especially biochar alleviated salinity-caused growth depressions, and improved Na/K ratio in salinity stressed plants. Reduced Na uptake of plants and reduced conductivity in biochar-ameliorated soils suggest that a likely mechanism involves ion adsorption to biochar surfaces. Our results suggest that plants depend on symbiotic microorganisms to fully exploit biochar benefits in soils, suggesting avenues for joint management in agriculture. Biochar may be advantageous in saline soils, but long-term studies are required before recommendations should be given. (C) 2015 Elsevier B.V. All rights reserved.
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26.
  • Hedlund, Katarina, et al. (författare)
  • Mycorrhizal colonization of plants in set-aside agricultural land
  • 2002
  • Ingår i: Applied Soil Ecology. - 0929-1393. ; 19:1, s. 71-78
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural overproduction has led the European Union to encourage long-term abandonment of agricultural land and the adoption of management practices which enhance transition to semi-natural grassland or forest. This paper reports the results of a field study conducted in newly abandoned agricultural land where the development of the mycorrhizal community was investigated in response to manipulation of the above-ground vegetation. The field site consisted of plots where the plant diversity was managed by (1) sowing 15 plant species, (2) sowing four plant species, and (3) allowing plots to be naturally colonized by plants. The plant mixture contained grasses, legumes and forbs that were all expected to occur on the site following succession. Each of the low diversity replicates contained a different subset of the high diversity mixture, in order to avoid confounding diversity effects with sampling effects. A subset of these plots was inoculated with soil cores from a later successional stage and the experiment was arranged in a randomized block design. The catch plants, Fagus sylvatica, Picea abies and Plantago lanceolata, were planted in the experimental plots and the presence of ecto- or arbuscular mycorrhizal (AM) fungi on their roots was determined. The level of AM colonization of P. lanceolata and the ectomycorrhizal colonization of F. sylvatica was lower in the sown treatments with high and low plant diversity compared to areas that were naturally colonized by plants. The survival of catch plants of the tree species was also higher in the naturally colonized plots. Soil inoculations had no effect on either of the mycorrhizal types or the survival of catch plants. The establishment of non-introduced woody plant species was more successful in the naturally colonized treatments. (C) 2002 Elsevier Science B.V All rights reserved.
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27.
  • Heijboer, Amber, et al. (författare)
  • Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a 15N tracer-based approach
  • 2016
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 107, s. 251-260
  • Tidskriftsartikel (refereegranskat)abstract
    • Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultaneously. In particular we studied how the chemical composition of organic amendments affects the biomass, activity and composition of the soil microbial community and subsequently carbon (C) and N mineralization, microbial N immobilization and plant growth and nutrient uptake. In a pot experiment, Brussels sprouts (Brassica oleracea, cvar. Cyrus) were grown on arable soil, mixed with 15N-labelled mineral fertilizer and different kinds of organic amendments (cattle manure solid fraction, maize silage, lucerne silage, wheat straw) differing in C:N ratio and lignin content. After 69 and 132 days, destructive sampling took place to assess the effects of the different treatments on soil microbial biomass (microscopic measurements), microbial community composition (phospholipid fatty acid profiles), soil microbial activity (14C-leucine incorporation), C and N mineralization, plant biomass and 15N retrieval in soil pools, microbial biomass and plant biomass. Addition of organic amendments increased soil microbial biomass, activity and fungal/bacterial ratio and created distinct microbial community compositions, whereby high C:N ratio organic amendments had stronger effects compared to low C:N ratio amendments. Structural equation modelling showed that higher values of soil microbial activity were associated with increased N mineralization rates, increased plant biomass and plant 15N uptake, while microbial 15N immobilization was associated with soil microbial community composition. The outcomes of this study highlight the importance of the chemical composition and the amount of the organic amendments for finding a balance between plant N uptake, microbial N immobilization and N retention in labile and stable soil pools through the effects on the composition and activity of the soil microbial community. The results provide insights that can be used in designing combined input (nutrient and organic) nutrient management strategies for a more sustainable agriculture.
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28.
  • Hydbom, Sofia, et al. (författare)
  • Reduced tillage stimulated symbiotic fungi and microbial saprotrophs, but did not lead to a shift in the saprotrophic microorganism community structure
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 119, s. 104-114
  • Tidskriftsartikel (refereegranskat)abstract
    • The need for sustainable agricultural systems, which for example enhance soil organic carbon (SOC) content, has increased the interest for management with reduced tillage. In this study we used a Swedish long-term (20 yrs.) systems experiment, including reduced tillage (harrowing 10 cm) and plowing (moldboard plow 0–20 cm) combined with three levels of nitrogen (N) fertilization. With this setup we tested if (1) the arbuscular mycorrhizal fungi (AMF) concentration and (2) the fungi to bacteria (F:B) ratio would be higher under reduced tillage than under conventional tillage, and if this would be associated with higher SOC concentrations. We also tested if (3) the microbial biomass C close to the surface would be higher under reduced tillage than conventional tillage. Furthermore, since disturbance can reduce respiration and microbial growth we tested if (4) this occurred in our reduced tillage system. In addition, we tested if (5) fertilization increased the growth rate of fungi and decreased that of bacteria. We collected soil samples in July and October and found that the microbial biomass C, measured in October only, was higher close to the surface in the reduced tillage treatment and so was the microbial respiration. The fungal and bacterial growth rate, on the other hand, were not affected by tillage treatment. Fertilization did not affect the bacterial growth rate but did have a positive effect on fungal growth rate. In accordance with our expectations reduced tillage had a stimulating effect on AMF and saprotrophic fungi, and contrary to our expectation, also bacteria were positively affected by reduced tillage. In line with the unchanged F:B ratio, we found no indication that even 20 years of reduced tillage increased SOC concentrations in the long term.
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29.
  • Iovieno, Paola, et al. (författare)
  • Soil microbial community structure and biomass as affected by Pinus pinea plantation in two Mediterranean areas
  • 2010
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 45:1, s. 56-63
  • Tidskriftsartikel (refereegranskat)abstract
    • Stone pine (Pinus pinea L.) has been widely introduced for afforestation in Mediterranean areas. Despite its wide distribution and its presence since ancient time, it is mostly considered as non-native to the Italian peninsula. Plantation of non-native species may have a strong impact on the soil microbial community and, consequently, on nutrient cycling and soil functions. The effect of stone pine on soil microbial community structure and biomass, as revealed by phospholipid fatty acid (PLFA) analysis and fungal biomass indicators, was investigated in two Mediterranean areas in south Italy, where the climax tree species was holm oak (Quercus ilex L.) and some patches were afforested with stone pine. We studied soils from two sites with different parent material, volcanic lava and limestone (calcareous soil). The soil pH range was wider in the calcareous than in the volcanic soils. At both sites, the soils under stone pine had lower pH and higher organic matter content than under holm oak. Microbial biomass was, on average, 1.3-1.4 fold higher in the soils under holm oak than under stone pine. The PLFA composition was different in soils under stone pine compared with holm oak, while the changes in PLEA composition induced by the different tree species were comparable at the two sites. The changes in the PLFA composition were significantly correlated to soil pH and relative concentrations of PLFA indicators (mol%) previously demonstrated to indicate pH effects were also correlated to pH. Thus, both in the volcanic and the calcareous soils, stone pine plantation affected soil microbial community structure and the mechanism for this change appeared to be soil pH changes. (C) Elsevier B.V. All rights reserved.
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30.
  • Korkeamäki, Timo, et al. (författare)
  • CEO power and matching leverage preferences
  • 2017
  • Ingår i: Journal of Corporate Finance. - : Elsevier BV. - 0929-1199. ; 45, s. 19-30
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the effect of managerial power on CEOs' tendency to imprint their personal leverage preferences upon the firms they manage. Using a unique data source that allows us to measure personal wealth and indebtness in great detail, we find a connection between CEOs' personal leverage and that of their firms. The connection is driven by the CEOs with a longer tenure and the CEOs who serve in a dual role. The connection is significantly weaker for those CEOs who have a proportion of their personal wealth tied to the firm. Presence of block holders also weakens the connection.
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31.
  • Labidi, S, et al. (författare)
  • Effects of compost addition on extra-radical growth of arbuscular mycorrhizal fungi in Acacia tortilis ssp raddiana savanna in a pre-Saharan area
  • 2007
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 35:1, s. 184-192
  • Tidskriftsartikel (refereegranskat)abstract
    • We studied the influence of added compost, consisting of Acacia cyanophylla leaves, on the production of extra-radical mycelia of arbuscular mycorrhizal (AM) fungi in natural stands of Acacia tortilis, which forms a desert savanna. Four different plots with different soil characteristics in terms of nutrient level and water-holding capacity were included in the study. The production of AM fungi was measured as the increase in the amount of the phospholipid fatty acid (PLFA) 16:1 omega 5 and the neutral lipid fatty acid (NLFA) 16:1 omega 5 in mesh bags placed in the root zone of A. tortilis trees. The production of AM mycelia was much higher at the site with the highest nutrient level and highest water holding capacity. Principal component analysis revealed that mesh bags from this plot had proportionally more PLFA 16:1 omega 5 than the other plots, indicating that this plot contained proportionally more AM fungi in the microbial community. Compost addition enhanced the production of AM mycelia in all plots although the response was greatest in the plot with the highest proportion of AM fungi. The beneficial effect of compost addition on growth of the AM fungal biomass found in this study could be one way to improve survival of planted seedlings in and regions. We suggest that indigenous AM fungi, which are adapted to the limiting conditions in the plots, are the preferable source of inoculum for improving the growth of A. tortilis in plantations in pre-Saharan ecosystems.
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32.
  • Manoharan, Lokeshwaran, et al. (författare)
  • Agricultural management practices influence AMF diversity and community composition with cascading effects on plant productivity
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 115, s. 53-59
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the effects of different agricultural practices on the mycorrhizal symbiosis is important for agricultural production and the sustainable use of soil. We investigated the composition and diversity of arbuscular mycorrhizal fungi (AMF) in soils from fields under different agricultural practices (conventional and organic cereal fields, leys and permanent pastures) in southern Sweden. The diversity of AMF was found to be greatest in permanent pastures, corroborating evidence that agricultural practices such as tillage impair AMF diversity. Neither geographical location nor soil type nor any of the major soil characteristics we measured impacted AMF diversity or community composition. AMF community composition was significantly affected by the different agricultural practices, particularly conventional management, which reduced AMF diversity. Of the cereal fields sampled, those under organic management held the greatest AMF diversity, and in a glasshouse experiment this greater diversity was positively related to barley phosphorus uptake and grain biomass production. Our results demonstrate the impact of different agricultural practices on AMF communities. In particular, we demonstrate the ability of organic farming to sustain greater AMF diversity relative to conventional farming, and the potential importance of this increased diversity for sustainable cereal production.
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33.
  • Medina, Almudena, et al. (författare)
  • The interactive effect of an AM fungus and an organic amendment with regard to improving inoculum potential and the growth and nutrition of Trifolium repens in Cd-contaminated soils
  • 2010
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 44:2, s. 181-189
  • Tidskriftsartikel (refereegranskat)abstract
    • Aspergillus niger-treated dry olive cake (DryOC) can be used as a soil organic amendment and the aim of this work was to study the effectiveness of this amendment and a Cd-adapted arbuscular mycorrhizal (AM) fungus in improving Trifolium repens growth and nutrition in Cd-contaminated soil. In a compartmentalized growth system, consisting of a root compartment (RC) and two hyphal compartments (HCs), we investigated the influence of the amendment on intraradical and extraradical AM fungi development. In addition, we studied the viability and infectivity of the detached extraradical mycelium in plants, designated as receptor plants, grown in the HC after removal of the RC. Both the amendment and the AM fungus increased shoot and root biomass and nodulation in both the non-contaminated and Cd-contaminated soils. The positive interaction between the microbiologically treated DryOC and the AM fungus resulted in the highest plant yield, which can be explained by enhanced nutrient acquisition and arbuscular richness as well as by the immobilisation of Cd in amended soils. However, A. niger-treated DryOC had no effect on the extraradical mycorrhizal mycelium development. Although Cd decreased AM hyphal length density, symbiotic infectivity was similar in receptor plants grown in non-contaminated and contaminated soil, thus confirming the AM fungal inoculum potential. The combination of the AM fungus and A. niger-treated DryOC increased plant tolerance to Cd in terms of plant growth and nutrition and can be regarded as an important strategy for reclaiming Cd-contaminated soils. (C) 2009 Elsevier B.V. All rights reserved.
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34.
  • Mårtensson, Linda-Maria, et al. (författare)
  • Allocation of carbon to mycorrhiza in the grasses Koeleria glauca and Corynephorus canescens in sandy grasslands
  • 2012
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 54, s. 55-62
  • Tidskriftsartikel (refereegranskat)abstract
    • By investigating both semi-natural and experimentally implemented pH variation in nutrient-poor sandy grasslands, we examined how soil decalcification may influence the arbuscular mycorrhizal (AM) fungal biomass in plant roots and in the soil, as well as the allocation of carbon (C) to AM fungal biomass. We estimated the amount of AM fungal mycelium, by using the fatty acid 16:1 omega 5, in the roots and in the soil surrounding the roots of two grass species in a pH gradient, and in one grass in an experimental area. We investigated the allocation of C to the AM fungi by using in situ C-13 labelling. Contrary to our expectations, we found a decrease in AM fungal mycelium in the soil with increasing soil pH, and no significant relationship between soil pH and the amount of AM fungi in the roots. We also found that the allocation of C below ground was very small in the grasses investigated: the excess of C-13 in the roots after five days was only between 0.06 and 1.2% of the excess of C-13 in the shoots directly after labelling. The allocation of C to the extraradical AM mycelium also decreased with increasing pH, ranging from not detectable to 1.2 mu g C-13 g(-1) dry soil in the range of soil pH from 5.5 to 8.5. Experimental manipulation of decalcification through soil perturbation further supported the finding that AM fungal density is higher in decalcified areas, although it was not statistically significant in this case. We conclude that the amount of AM fungi is very low in this type of nutrient and drought stressed habitat, and that a high pH in the topsoil does not leads to higher AM fungal biomass. (C) 2012 Elsevier B.V. All rights reserved.
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35.
  • Mårtensson, Linda-Maria, et al. (författare)
  • Reductions in microbial biomass along disturbance gradients in a semi-natural grassland
  • 2012
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 62, s. 8-13
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil disturbance is a common phenomenon in semi-natural sandy grasslands, caused by management practices, livestock trampling and erosion. To better understand ecosystem processes when the surface layers of the soil are disturbed, we investigated the effects of disturbance on different functional microbial groups by the use of signature fatty acid analysis. Four levels of disturbance were investigated in local disturbance gradients in an area with semi-natural sandy grassland. Festuca brevipila Tracey (Poaceae) was used as the study plant to investigate the response of plant and microbial biomass to disturbance. The plant was chosen since it dominated the site and was present at all levels of disturbance. The amount of arbuscular mycorrhizal (AM) fungi in the roots of the study plant was not affected by soil disturbance. The amount of AM fungi, saprotrophic fungi and bacteria in the soil was significantly reduced by increasing level of soil disturbance, coinciding with a reduced vegetation cover and decreasing soil organic matter content. Increasing levels of soil disturbance resulted in elevated soil pH and concentration of inorganic N, whereas the water content and organic matter content was reduced. The shoot N:P ratios of the grass investigated increased with the level of disturbance. We conclude that soil disturbance disfavours fungi due to mechanical interruption of hyphae and through reduced plant biomass. We also conclude that soil disturbance disfavours bacteria in the long run due to reduced organic matter content. (c) 2012 Published by Elsevier B.V.
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36.
  • Palmu, Erkki, et al. (författare)
  • Can δD and δ18O stable isotopes be used to detect long-range dispersal among carabid beetles?
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 119, s. 99-103
  • Tidskriftsartikel (refereegranskat)abstract
    • We studied if hydrogen (δD) and oxygen (δ18O) stable isotope values in three common carabid species in intensively managed agricultural landscapes in southernmost Sweden indicate long-range dispersal. We matched “emerging” (emergence tents) and “colonizing” (pitfall traps) individuals of three carabid species (Trechus quadristriatus, Harpalus rufipes, Pterostichus melanarius) to account for spatial and seasonal variability. There was higher dispersion of δD values among H. rufipes individuals as compared to values of the other two species, which suggests that H. rufipes individuals had the most variable spatial natal origin. The δD values were significantly lower among colonizing compared to emerging individuals in the flight capable and carnivorous species T. quadristriatus. This result suggests long-range migration of T. quadristriatus individuals from remote locations with deuterium depleted (lower δD) meteoric water. Our study provides a first effort towards understanding the δD and δ18O dynamics in epigean carabids in northern European agroecosystems. Additional research on larger (preferably continental) spatial scales and experimental trials that attempt to disentangle major unaccounted sources of variation and decoupling of δD and δ18O among carabids and other invertebrate natural enemies is urgently needed to allow a more frequent use of δD and δ18O dynamics as indicators of long-range dispersal.
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37.
  • Ravid, S. Abraham, et al. (författare)
  • Large investors’ portfolio composition and firms value
  • 2020
  • Ingår i: Journal of Corporate Finance. - : Elsevier BV. - 0929-1199. ; 61
  • Tidskriftsartikel (refereegranskat)abstract
    • We analyze new Swedish data on the portfolio holdings of large blockholders and find that firm value increases with the weight of a stock in a large blockholder's portfolio. In our sample, this weight may be greater than 50%. We are the first to show that this value premium is correlated with portfolio weights for any large blockholders, not just institutions. We find some evidence that indicates that “stock importance” (high portfolio weight) can mitigate the negative effects of a dual-class structure on firm value. Further, it does not seem that a large blockholder's tenure as a CEO or as a board chairman affects this value premium. We conduct a variety of tests to rule out endogeneity and reverse causality.
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38.
  • Rinnan, Riikka, et al. (författare)
  • Effects of litter addition and warming on soil carbon, nutrient pools and microbial communities in a subarctic heath ecosystem
  • 2008
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 39:3, s. 271-281
  • Tidskriftsartikel (refereegranskat)abstract
    • Climatic warming leads to the expansion of deciduous shrubs and trees in the Arctic. This leads to higher leaf litter inputs, which together with warming may alter the rate of carbon and nutrient cycling in the arctic ecosystems. We assessed effects of factorial warming and additional litter on the soil ecosystem of a subarctic heath in a 7-year-long field experiment. Fine root biomass, dissolved organic carbon (DOC) and total C concentration increased in response to warming, which probably was a result of the increased vegetation cover. Litter addition increased the concentration of inorganic P in the uppermost 5 cm soil, while decreasing the pool of total P per unit area of the organic profile and having no significant effects on N concentrations or pools. Microbial biomass C and N were unaffected by the treatments, while the microbial biomass P increased significantly with litter addition. Soil ergosterol concentration was also slightly increased by the added litter in the uppermost soil, although not statistically significantly. According to a principal component analysis of the phospholipid fatty acid profiles, litter addition differed from the other treatments by increasing the relative proportion of biomarkers for Gram-positive bacteria. The combined warming plus litter addition treatment decreased the soil water content in the uppermost 5 cm soil, which was a likely reason for many interactions between the effects of warming and litter addition. The soil organic matter quality of the combined treatment was also clearly different from the control based on a near-infrared reflectance (NIR) spectroscopic analysis, implying that the treatment altered the composition of soil organic matter. However, it appears that the biological processes and the microbial community composition responded more to the soil and litter moisture conditions than to the change in the quality of the organic matter.
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39.
  • Rinnan, Riikka, et al. (författare)
  • Long-term warming of a subarctic heath decreases soil bacterial community growth but has no effects on its temperature adaptation
  • 2011
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 47:3, s. 217-220
  • Tidskriftsartikel (refereegranskat)abstract
    • We tested whether bacterial communities of subarctic heath soil are adapted to elevated temperature after experimental warming by open-top greenhouses for 7 or 17 years. The long-term warming by 1-2 degrees C significantly decreased bacterial community growth, by 28% and 73% after 7 and 17 years, respectively. The decrease was most likely due to decreased availability of labile substrate under warming. However, we found no evidence for temperature adaptation of soil bacterial communities. The optimum temperature for bacterial growth was on average 25 C, and the apparent minimum temperature for growth between -7.3 and -6.1 degrees C. and both were unaffected by warming. (C) 2011 Elsevier B.V. All rights reserved.
  •  
40.
  • Rousk, Johannes, et al. (författare)
  • Assessing plant-microbial competition for P-33 using uptake into phospholipids
  • 2007
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 36:2-3, s. 233-237
  • Tidskriftsartikel (refereegranskat)abstract
    • A novel method of estimating soil microbial P uptake, using P-33 incorporation into the phospholipids in soil microbial biomass, was used in a study of P-competition between plants and microorganisms. The microbial biomass, and thus the competition for the added P-33, was altered by using different glucose treatments in a microcosm set-up. There was obvious competition for P-33, as shown by the negative relationship between P-33 uptake by the plant and P-33 incorporation into microbial phospholipids. The data thus indicate that soil microorganisms partly control P-33 uptake by the plant. The suggested method of measuring P-33 in phospholipids appears to have the potential to provide a rapid alternative to techniques such as chloroform fumigation-extraction for the determination of microbial P uptake, although at present the method will only give relative estimates of P uptake.
  •  
41.
  • Stone, D., et al. (författare)
  • A method of establishing a transect for biodiversity and ecosystem function monitoring across Europe
  • 2016
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 97, s. 3-11
  • Tidskriftsartikel (refereegranskat)abstract
    • The establishment of the range of soil biodiversity found within European soils is needed to guide EU policy development regarding the protection of soil. Such a base-line should be collated from a wide-ranging sampling campaign to ensure that soil biodiversity from the majority of soil types, land-use or management systems, and European climatic (bio-geographical zones) were included. This paper reports the design and testing of a method to achieve the large scale sampling associated with the establishment of such a baseline, carried out within the remit of the EcoFINDERS project, and outlines points to consider when such a task is undertaken. Applying a GIS spatial selection process, a sampling campaign was undertaken by 13 EcoFINDERS partners across 11 countries providing data on the range of indicators of biodiversity and ecosystem functions including; micro and meso fauna biodiversity, extracellular enzyme activity, PLEA and community level physiological profiling (MicroResp (TM) and Biolog (TM)). Physical, chemical and bio-geographical parameters of the 81 sites sampled were used to determine whether the model predicted a wide enough range of sites to allow assessment of the biodiversity indicators tested. Discrimination between the major bio-geographical zones of Atlantic and Continental was possible for all land-use types. Boreal and Alpine zones only allowed discrimination in the most common land-use type for that area e.g. forestry and grassland sites, respectively, while the Mediterranean zone did not have enough sites sampled to draw conclusions across all land-use types. The method used allowed the inclusion of a range of land-uses in both the model prediction stage and the final sites sampled. The establishment of the range of soil biodiversity across Europe is possible, though a larger targeted campaign is recommended. The techniques applied within the EcoFINDERS sampling would be applicable to a larger campaign. (C) 2015 Elsevier B.V. All rights reserved.
  •  
42.
  • Söderberg, Katarina, et al. (författare)
  • The microbial community in the rhizosphere determined by community-level physiological profiles (CLPP) and direct soil- and cfu-PLFA techniques
  • 2004
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 25:2, s. 135-145
  • Tidskriftsartikel (refereegranskat)abstract
    • The composition of the microbial community in the rhizosphere was investigated using three different techniques: direct soil-phospholipid fatty acid (PLFA), cfu-PLFA (using culturable, bacteria only) and community-level physiological profiles (CLPP) using Biolog GN microtitre plates. All three techniques showed that the rhizosphere bacterial community differed from the bulk soil community, when pea plants were grown in pots. The two PLFA techniques also indicated that the effect of roots on microbial communities was greater than differences in the PLFA pattern between different bulk soils. The difference was most prominent using the direct soil-PLFA technique. Both PLFA techniques indicated that gram-negative bacteria were relatively more abundant in the rhizosphere, while PLFAs indicative of gram-positive bacteria were relatively more common in bulk soil samples. The results obtained with the direct soil-PLFA method did not differ between rhizosphere samples taken along a pea root, while this was the case with both the cfu-PLFA technique and the CUP method. According to both techniques, the differences in community composition were greatest near the root tip. Different plant species exhibited different microbial community composition in the rhizosphere, as judged from all three methods, when four different plant species were compared. In all cases, Trifolium differed most from the other species (three different grasses). Although all three methods were found to be suitable for rhizosphere studies, the CLPP method appeared less suitable than the two PLFA methods, since less of the variation in the data could usually be explained.
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43.
  • Valentin, Lil (författare)
  • Use of colour and spectral Doppler ultrasound examination in gynaecology
  • 1997
  • Ingår i: European Journal of Ultrasound. - 0929-8266. ; 6:3, s. 143-163
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To review and sum up the published literature on gynecological Doppler ultrasound examination. Methods: Publications on gynecological Doppler ultrasound examination already known by the author, publications found in the bibliographic database Medline, and publications found in the reference lists of available studies were read, and relevant information was extracted and summarized. Results: Reference data representative of normal findings at transvaginal color and spectral Doppler ultrasound examination of the uterine and ovarian arteries have been established in healthy pre- and post-menopausal women and in normal early pregnancies. Blood flow velocities in the uterine and ovarian arteries change during the normal menstrual cycle and are very different in pre- and post-menopausal women. Lower blood flow velocities and higher pulsatility index (PI) values have been recorded in the ovarian arteries after the menopause. Uterine artery blood flow velocities increase and uterine artery PI values and resistance index (RI) values decrease with gestational age in the first trimester. There is not yet an established role of the gynecological Doppler ultrasound examination in clinical practice. It remains unclear whether the gynecological Doppler ultrasound examination contributes substantially to the clinical management of early pregnancy complications or infertility problems, to the differential diagnosis of pelvic masses or uterine pathology. Conclusions: Large prospective studies-preferably randomized controled trials-are needed to determine the clinical value of the gynecological Doppler ultrasound examination.
  •  
44.
  • Williams, Alwyn, et al. (författare)
  • Indicators and trade-offs of ecosystem services in agricultural soils along a landscape heterogeneity gradient
  • 2014
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 77, s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil functions can be classified as supporting (nutrient cycling) and provisioning (crop production) ecosystem services (ES). These services consist of multiple and dynamic functions and are typically assessed using indicators, e.g. microbial biomass as an indicator of supporting services. Agricultural intensification negatively affects indicators of soil functions and is therefore considered to deplete soil ES. It has been suggested that incorporating leys into crop rotations can enhance soil ES. We examined this by comparing indicators of supporting soil services - organic carbon, nitrogen, water holding capacity and available phosphorous (carbon storage and nutrient retention); net nitrogen mineralisation rate and microbial biomass (nutrient cycling and retention) - in barley fields, leys and permanent pastures along a landscape heterogeneity gradient (100, 500 and 1000 m radii). In addition, barley yields (provisioning service) were analysed against these indicators to identify trade-offs among soil services. Levels of most indicators did not differ between barley and ley fields and were consistently lower than in permanent pastures. Leys supported greater microbial biomass than barley fields. Landscape heterogeneity had no effect on the indicators or microbial community composition. However, landscape heterogeneity correlated negatively with yield and soil pH, suggesting that soils in heterogeneous landscapes are less fertile and therefore have lower yields. No trade-offs were found between increasing barley yield and the soil indicators. The results suggest that soil ES are determined at the field level, with little influence from the surrounding landscape, and that greater crop yields do not necessarily come at the expense of supporting soil services. (C) 2014 Elsevier B.V. All rights reserved.
  •  
45.
  • Williams, Alwyn, et al. (författare)
  • Indicators of soil ecosystem services in conventional and organic arable fields along a gradient of landscape heterogeneity in southern Sweden
  • 2013
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 65, s. 1-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural intensification has been vital for meeting global food demand but has caused environmental degradation. This has disrupted the ability of soil to provide vital ecosystem services. Organic farming is often thought to conserve and utilise soil ecosystem services, and thus be a more sustainable method of food production than conventional farming. However, evidence for this is equivocal, and little is known of the potential trade-offs between soil functions, which can be classified as supporting and provisioning ecosystem services, in conventional and organic systems. In addition, few studies have simultaneously examined how surrounding landscape heterogeneity affects soil functions in agriculture. In this study we investigated the effects of farming method (conventional versus organic) and landscape heterogeneity (100 m, 500 m and 1000 m radius) on indicators of soil ecosystem services: soil organic carbon (SOC), total nitrogen (TN), water holding capacity (WHC) and plant-available phosphorous (P) (measures of carbon storage and nutrient retention); net N mineralisation and microbial community composition and biomass (nutrient cycling); and crop yield. We found no effect of landscape heterogeneity, and no differences in any of the measured soil and microbial variables between conventional and organic farms, apart from net N mineralisation, which was higher in organic farms. However, conventional farms had significantly greater yield than organic farms, and there was no apparent trade-off between increasing yield and the level of supporting ecosystem services. The organic farms in this study appear to have been intensively managed, with a straight substitution of organic inputs for chemicals, but little other effort to enhance soil fertility. For example, the organic farms applied large quantities of manure compared with conventional farms but conducted mechanical weeding (harrowing), whereas conventional farms applied herbicides. This repeated soil disturbance may cause rapid organic matter mineralisation and undermine the ability of these organic farms to retain carbon and nitrogen. The terms ‘organic’ and ‘conventional’ agriculture both cover a wide variety of farming methods, some of which enhance or deplete ecosystem services more than others. To develop truly sustainable methods of agriculture, research should focus on the effects of specific farming practices, rather than the labels ‘conventional’ and ‘organic’.
  •  
46.
  • Arrazola Vasquez, Elsa, et al. (författare)
  • Earthworm burrowing modes and rates depend on earthworm species and soil mechanical resistance
  • 2022
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 178
  • Tidskriftsartikel (refereegranskat)abstract
    • Earthworms drive multiple soil processes, but their specific impact on soil functions differs between earthworm species and ecological categories. A key challenge in modern agriculture is soil compaction due to heavy ma-chinery, but we have limited quantitative knowledge about how the burrowing activity of different earthworm species is affected by compaction. Here, we address this question in a laboratory experiment with 2-D terraria, where we used Aporrectodea caliginosa (Savigny, 1826) and Aporrectodea longa (Ude, 1885) as representatives of two different ecological categories. We exposed both species to four different soil mechanical resistance levels and monitored their burrowing activity for three days. We quantified burrowing rates and cast production, assessed the burrowing mode, and estimated energy requirements as a function of soil mechanical resistance. The results showed that the burrowing rates of both earthworm species significantly decreased with increasing soil mechanical resistance, but that the impact was species-dependent and lower for A. longa. Earthworms changed their burrowing mode towards ingestion when soil mechanical resistance increased, and this shift was more prominent for A. caliginosa that primarily burrowed via cavity expansion (i.e. by pushing soil aside) at low soil mechanical resistance. We further show that energy requirement and cast produced per unit burrow length increased with soil mechanical resistance. Our study revealed significant and species-dependent adverse effects of soil mechanical resistance on earthworm burrowing, which in turn has consequences for many soil processes mediated by earthworms, such as water infiltration, soil aeration, nutrient cycling and soil organic matter turnover.
  •  
47.
  • Banerji, S., et al. (författare)
  • Money as a weapon: Financing a winner-take-all competition
  • 2021
  • Ingår i: Journal of Corporate Finance. - : Elsevier BV. - 0929-1199. ; 66
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate the capital structure of pioneering startup firms, which are frequently credited with opening new markets and niches in the digital era and often face the threat of the potential entry of successful, cash-rich firms from adjacent markets. Our analysis is made in the context of a winner-take-all competition in the form of an all-pay auction for the monopolistic position in a new market. We show that a pioneer's optimal capital structure exhibits widespread diversity and is determined by a tradeoff between entry deterrence and post-entry competition intensification. A pure-equity (a mixture of equity and risky debt) structure is optimal when (1) barriers to entry are small (large), (2) the future prospect of the new market is fairly certain and/or, (3) the new market is likely (unlikely) to create large externalities on the potential entrant's existing business. The post-entry competition is likely to engender large losses to both the winner and the loser. © 2020 Elsevier B.V.
  •  
48.
  • Barreiro, Ana, et al. (författare)
  • Soil bacteria respond to regional edapho-climatic conditions while soil fungi respond to management intensity in grasslands along a European transect
  • 2022
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 170
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil microbial community structure is determined by environmental conditions and influenced by other factors, such as the intensity of the land use management. Studies addressing the effect of environmental factors and management on grassland soil microbial communities at the continental scale are missing, and the wide range of ecosystem services provided by these ecosystems are thus also wanting. To address this knowledge gap, this study presents data on grassland soil microbial communities along a pan-European agro-ecological gradient. The transect included five geographical locations (Sweden, Germany, Switzerland, Portugal mainland, Portugal Azores). At each location, soils were collected in two regions characterized by favourable and less favourable conditions for plant growth. In each of these ten regions, grasslands along a gradient of management intensity were selected, i.e. grassland under intensive, less intensive and extensive management. Phospholipid fatty acid analysis (PLFA) was used to characterize the microbial community structure (PLFA pattern) in relation to climatic and soil properties. Over the whole geographical range, the environmental properties determined the soil microbial community structure. In Sweden and Switzerland, the regional growth conditions had the strongest influence on the soil microbial communities, while in Germany, Portugal mainland and Azores the management intensity was more important. Splitting up this whole community response into individual groups reveals that, in general, saprotrophic fungal biomarkers were highest in extensively managed grasslands while bacterial biomarkers differed mainly between the regions. We conclude that at the transect level, climate and soil properties were the most important factors influencing soil bacterial community structure, while soil fungal groups were more responsive to grassland management intensity. Overall agricultural sustainability could benefit from informed soil health promoting management practices, and this study contributes to such knowledge, showing the importance of management for the soil microbial biomass and community structure.
  •  
49.
  • Bisang, Irene, et al. (författare)
  • Three decades of field surveys reveal a decline of arable bryophytes in the Swiss lowlands despite agri-environment schemes
  • 2021
  • Ingår i: Agriculture, Ecosystems & Environment. Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 313
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural intensification represents one of the major drivers for the dramatic loss of biodiversity worldwide. To halt the decline of farmland biodiversity, Switzerland adopted agri-environment schemes (AES) in 1998. Here, we monitored the occurrence, abundance and habitats of two species of arable bryophyte specialists, the Field hornwort (Anthoceros agrestis) and the Carolina hornwort (Phaeoceros carolinianus), in 28 crop fields in the intensively cultivated Swiss Plateau from 1991–2018, to investigate the effects of arable management, AES directives, and weather conditions on their performance. The target species are characteristic of the specialized short-lived arable bryophyte flora of Central Europe that depend on bare substrate in low-intensively cultivated and regularly ploughed fields. Trends in their occurrence thus reflect in many respects the status of the arable bryophytes in cultivated fields. Hornwort occurrence significantly declined between 1991 and 2018. A strong decrease in stubble fields that remain unmanaged after harvest, the favourite habitat for many arable specialists in the study area, largely accounted for the decline. Stubble fields nearly disappeared in the study area because of a gradual reduction in the cultivation area of cereals and the increasing practice of immediate post-harvest tillage. The latter is common in intensive arable farming and was accentuated by AES directives amended in 2005. Hornwort occurrences were positively affected by high air humidity during summer, but weather effects were subordinate to management effects. We propose tailored amendments of AES regulations, that aremented at selected sites, to maintain the characteristic arable specialist bryophytes in the Swiss Plateau: crop rotation with adequate proportions of cereals that are regularly ploughed but not before the end of October, no post-harvest processing of stubble fields, and optimization of the existing instrument ‘Biodiversity Promoting Areas’, e.g., short-term fallows in crop fields. Late-autumn or overwintering stubbles and short-term fallows will benefit many other organisms that depend on extensively managed open habitats, for example arableflowers, farmland breeding birds and specialized arthropods
  •  
50.
  • Brown, James R., et al. (författare)
  • Government lending in a crisis
  • 2021
  • Ingår i: Journal of Corporate Finance. - : Elsevier BV. - 0929-1199 .- 1872-6313. ; 71, s. 102116-
  • Tidskriftsartikel (refereegranskat)abstract
    • The economic disruption from the COVID-19 pandemic prompted governments around the world to initiate an unprecedented number of temporary lending and tax deferment programs. Which firms will benefit from these programs? What are the implications for firm balance sheets and post-crisis survival? We provide some novel insights on these questions by studying one of the first government programs of this type, which Sweden launched at the height of the 2008-2009 financial crisis. The Swedish program allowed firms to temporarily suspend payment of all labor-related taxes and fees, treating these deferred amounts as a short-term loan from the government. Firms participating in the program are younger, less profitable, hold fewer cash reserves, are more leveraged, and have less unused slack in their credit lines when the crisis hits. Given the structure of the Swedish program, it provided more liquidity to firms with relatively larger ex ante wage bills. Exploiting this feature of the policy, we find that firms use the program to increase overall debt levels rather than to substitute for other borrowing. The leverage increase is due entirely to higher levels of non-bank debt. Firms use the funds to avoid making even deeper cuts to current assets. Despite the increase in leverage, access to the lending program is unrelated to the likelihood a firm files for bankruptcy and is negatively related to the likelihood a firm encounters severe financial distress in the years immediately following the crisis.
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