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1.
  • 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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2.
  • 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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3.
  • Abubaker, Jamal, et al. (författare)
  • Bacterial community structure and microbial activity in different soils amended with biogas residues and cattle slurry
  • 2013
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 72, s. 171-180
  • Tidskriftsartikel (refereegranskat)abstract
    • Anaerobic digestion of organic materials generates residues of differing chemical composition compared to undigested animal manures, which may affect the soil microbial ecosystem differently when used as fertilizers. This study investigated the effects of two biogas residues (BR-A and BR-B) and cattle slurry (CS) applied at rates corresponding to 70 kg NH4+-N ha(-1) on bacterial community structure and microbial activity in three soils of different texture (a sandy, a clay and an organic clay soil). 16S rRNA genes were targeted in PCR reactions and bacterial community profiles visualized using terminal restriction fragment length polymorphism. General microbial activity was measured as basal respiration (B-resp), substrate-induced respiration (SIR), specific growth rate (mu(SIR)), metabolic quotient (qCO(2)) and nitrogen mineralization capacity (NMC). Non-metric multidimensional scaling analysis visualized shifts in bacterial community structure related to microbial functions. There were significant differences in bacterial community structure after 120 days of incubation (+20 degrees C at 70% of WHC) between non-amended (control) and amended soils, especially in the sandy soil, where CS caused a more pronounced shift than biogas residues. Terminal-restriction fragment (TRF) 307, the predominant peak in CS-amended sandy soil, was identified as possibly Bacillus or Streptococcus. TRF 226, the dominant peak in organic soil amended with BR-B, was classified as Rhodopseudomonas. B-resp significantly increased and SIR decreased in all amendments to organic soil compared with the control, potentially indicating decreased efficiency of heterotrophic microorganisms to convert organic carbon into microbial biomass. This was also reflected in an elevated qCO(2) in the organic soil. The mu(SIR) level was higher in the sandy soil amended with BR-A than with BR-B or CS, indicating a shift toward species capable of rapidly utilizing glucose. NMC was significantly elevated in the clay and organic soils amended with BR-A and BR-B and in the sandy soil amended with BR-B and CS. Thus, biogas residues and cattle slurry had different effects on the bacterial community structure and microbial activity in the three soils. However, the effects of biogas residues on microbial activities were comparable in magnitude to those of cattle slurry and the bacterial community structure was less affected. Therefore, we do not see any reason not to recommend using biogas residues as fertilizers based on the results presented. (C) 2013 Elsevier B.V. All rights reserved.
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4.
  • 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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5.
  • 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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6.
  • 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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7.
  • 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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8.
  • 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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9.
  • 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.
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10.
  • Ayuke, Fredrick, et al. (författare)
  • Effects of biocontrol bacteria and earthworms on the severity of Alternaria brassicae disease and the growth of oilseed rape plants (Brassica napus)
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 117-118, s. 63-69
  • Tidskriftsartikel (refereegranskat)abstract
    • Biological control of plant diseases through the addition of microbial biocontrol agents and the promotion of earthworms can be an environmentally friendly alternative to the chemical control of plant diseases. However, possible risks with biocontrol agents and their interactions with earthworms and other soil biota have not been well studied. The aim of this study was to assess whether the beneficial bacterium Bacillus amyloliquefaciens and the earthworms Aporrectodea caliginosa or Aporrectodea longa could reduce disease in oilseed rape (Brassica napus) challenged with the pathogen Alternaria brassicae. Plant growth and productivity were measured as plant survival, height, biomass, and flower development as well as disease index. A second objective was to assess whether the presence of the bacterium at high concentrations would influence the survival, growth, and reproduction of the earthworms. One outdoor and one greenhouse experiment were performed with Br. napus plants challenged with AL brassicae inoculated to the plant leaves in the presence or absence of Bacillus amyloliquefaciens inoculated to the root environment and in the presence or absence of earthworms (Ap. caliginosa or Ap. longa) added to the soil. All treatments were replicated three times. In the outdoor experiment, inoculation with AL brassicae reduced the growth of plants and the addition of Ap. caliginosa increased plant height. In the greenhouse experiment, pairwise comparisons of plants challenged with AL brassicae showed that treatment with B. amyloliquefaciens led to significantly lower disease index than the treatment with Ap. caliginosa plus B. amyloliquefaciens, while other treatments had intermediate disease indices. The addition of AL brassicae or B. amyloliquefaciens increased the survival and mass increment of Ap. caliginosa as a main effect when used separately but not when used in combination.This study did not give any clear indication of the usefulness of B. amyloliquefaciens for biocontrol of plant pathogens such as AL brassicae when growing plants in natural soil. In addition, no significantly positive effects from the tested earthworm species were seen.
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11.
  • Bargaz, Adnane, et al. (författare)
  • Species interactions enhance root allocation, microbial diversity and P acquisition in intercropped wheat and soybean under P deficiency
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 120, s. 179-188
  • Tidskriftsartikel (refereegranskat)abstract
    • Belowground interactions in grain legume-cereal intercrops may improve resource acquisition and adaptation to environmental constraints such as phosphorus (P) deficiency. To advance the knowledge of belowground facilitative mechanisms involved in P-deficiency tolerance (root allocation, biochemical and microbial responses), soybean (Glycine max) and wheat (Triticum aestivum) were grown as monocrops and intercrops under P-deficiency and P-sufficiency conditions in soil-filled rhizoboxes. The hypothesis was that intercropping stimulates root microbial diversity, root biomass allocation and P-hydrolyzing acid phosphatases (APase) activity in roots under P-deficient conditions. Total root dry weight (RDW), length, and surface area significantly increased in P-deficient intercropped wheat and soybean. Greater root allocation to deeper soil layers was evident for P-deficient intercropped wheat. Shallow roots of intercropped wheat exhibited highly stimulated APase activity under P-deficient conditions while shallow roots of monocropped soybean exhibited higher APase activity in comparison to deeper roots, irrespective of P treatment. Root fungal diversity was significantly (p < 0.05) higher in intercropped wheat, and was significantly correlated with RDW, root APase activity, shoot P, and soil available P (rho = 0.24, p= 0.01). Root bacterial diversity was higher in both intercrops, and was significantly correlated with RDW and shoot N concentration. The observed shifts in root microbial diversity, root biomass allocation and APase activity provide explanatory mechanisms of relationships between rhizosphere heterogeneity and pathways for increased P acquisition in diversified crops. Advanced belowground metabolomics on root microbial communities are required to reveal the beneficial effect of root microorganisms in associations of different crop species.
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12.
  • 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.
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13.
  • Bengtsson, Jan (författare)
  • The response of springtails to fire in the fynbos of the Western Cape, South Africa
  • 2016
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 108, s. 165-175
  • Tidskriftsartikel (refereegranskat)abstract
    • Although fire is a natural form of disturbance in many ecosystems, the frequency of fires is increasing due to human activities. Hence, understanding the impacts of fire on biodiversity and ecosystem functioning has become increasingly important. In this study we investigated the effects of a large-scale fire on an important soil-dwelling group, springtails (Collembola), one year before and for three consecutive years after a fire in the fire-prone fynbos ecosystem in South Africa. In particular, we investigate the resistance of the springtail assemblages (i.e. their ability to remain relatively unchanged in the face of a disturbance), and their resilience (i.e. ability to return to a pre-disturbance state). To do this we sampled two sites with contrasting vegetation (Erica and Protea) and used three different standardized litter types in litterbag traps. A total of 35 springtail species from 31 genera and 14 families was found. The springtail assemblages in this fynbos system showed slightly more resistance to fire than resilience after the fire event, though substantial variation was found among vegetation types. Mean species richness and abundance per litterbag varied among the Protea and Erica sites, with resistant species being dominant in the Erica site, while species that showed an increase after the fire were dominant in the Protea site. Differences were also found between life forms: atmobiotic (free-living in vegetation) and epiedaphic (surface dwelling) species showed a significant decline in mean species richness directly after the fire in the Erica site. Euedaphic (soil-dwelling) species richness remained unchanged post-fire in the Erica site, while actually slightly increasing after the fire in the Protea site. Although the fynbos springtail assemblages had not fully recovered to pre-fire abundance after three years, many species appear to be resistant to or recover rapidly after fires, at least as ascertained over the relatively short (four years) duration of the study. It is likely that this response is influenced by the presence of suitable refugia within sites and by species-specific traits. Given changing fire regimes and the increasing frequency of fires due to human disturbances, the system will likely become more dominated by resistant springtail species preferring nutrient rich circumstances and easily decomposed litters. (C) 2016 Elsevier B.V. All rights reserved.
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14.
  • 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
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15.
  • Björsell, Pia, et al. (författare)
  • Interactions between some plant-parasitic nematodes and Rhizoctonia solani in potato fields
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 113, s. 151-154
  • Tidskriftsartikel (refereegranskat)abstract
    • The pathogenic fungus Rhizoctonia solani causes major economic losses for potato producers in Sweden. Producers, as well as extension officers, have reported possible increases in severity of R. solani when free-living plant-parasitic nematodes are present and active. The aim of this study was to investigate possible interactions and spatial correlations between root-lesion nematodes (Pratylenchus spp.), stubby-root nematodes (Trichodoridae) and the severity of stem canker caused by the fungus R. solani under field conditions. Nematodes in the genus' Globodera were also included after finding high numbers of these potato cyst nematode juveniles in the samples. Soil samples were taken in eight potato fields, located in the middle part of Sweden, with observed outbreaks of soil-borne stem canker caused by R. solani. Grading of stem canker and soil collections for nematode extraction were performed along transects starting from the centre of field patches with observed stem canker. There was no difference in the number of nematodes within the patches for any of the investigated nematode taxa, but the severity of stem canker was higher on plants graded in the centre of the patches compared to those graded in the margins. In addition, there was a spatial correlation between R. solani and stubby-root nematodes as well as potato cyst nematodes, but not for root-lesion nematodes. These results show that there is an interaction between plant-parasitic nematodes and R. solani in the field and this knowledge is of importance for future decisions of appropriate management methods. (C) 2017 The Authors. Published by Elsevier B.V.
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16.
  • 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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17.
  • Campbell, Colin (författare)
  • The arbuscular mycorrhizal fungus Glomus hoi can capture and transfer nitrogen from organic patches to its associated host plant at low temperature
  • 2011
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 48, s. 102-105
  • Tidskriftsartikel (refereegranskat)abstract
    • Arbuscular mycorrhizal fungi have been suggested to be of potential benefit in achieving sustainable agriculture systems. However, there is conflicting information on the degree to which arbuscular mycorrhizal fungi (AMF) can grow and function at soil temperatures typical of temperate regions. To resolve this conflict we grew Plantago lanceolata L inoculated with Glomus hoi (UY 110) in microcosm units maintained at 12/10 degrees C (day/night). The microcosms had two compartments, one planted and one not. The root-free compartment contained either an organic ((15)N:(13)C labelled milled shoot material) or a sand patch. When permitted access, G. hoi proliferated hyphae extensively in the organic patch material. Plant (15)N content was a simple function of length density of extra-radical mycelium (ERM) in the patch and c. 6% of host plant N was derived from the patch. These results indicate that G. hoi not only grew at these realistic soil temperatures, but also conferred a nutritional benefit to its host. (C) 2011 Elsevier B.V. All rights reserved.
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18.
  • Castaño Soler, Carles (författare)
  • Contrasting fungal functional groups influence nutrient cycling across four Japanese cool-temperate forest soils
  • 2024
  • Ingår i: Applied Soil Ecology. - 0929-1393 .- 1873-0272. ; 198
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding soil dynamics and nutrient cycling is crucial for the sustainable management of Japanese forests covering 70 % of the national land area. These forests are dominated by tree species with contrasting traits, influencing soil dynamics differently. We investigated how changes in soil characteristics across different forest stands shift in composition and functioning of fungal communities. Four different forest stands dominated by two different mycorrhizal types were selected: Fagus crenata and Larix kaempferi, representing ectomycorrhizal (ECM) types, and Cryptomeria japonica and Robinia pseudoacacia, representing arbuscular mycorrhizal (AM) types. In total, 62 composite topsoil samples from two depths were analyzed for their physicochemical properties and fungal communities were profiled by DNA sequencing. Ectomycorrhizal fungi dominated soils of Fagus crenata and Larix kaempferi forests, while fungal saprotrophs were more abundant in Cryptomeria japonica and Robinia pseudoacacia forests. Forest stand type rather than soil depth determined the composition and structure of soil fungal communities. Soil pH was positively correlated with abundances of saprotrophic fungi (P < 0.05) and negatively with ECM fungi. Soil C:N ratio was positively correlated, and nitrate was negatively correlated with relative abundances of root -associated fungi, primarily ECM fungi. No links between C nor N stocks with fungal guilds were found across the dataset. Observed links between soil C:N ratio and relative abundances of rootassociated fungi and saprotrophs stress the importance of these guilds for influencing nutrient cycling economy across contrasting forest types. The lack of correlation between fungal communities and soil C and N stocks suggests distinct mechanisms driving stocks in these soils.
  •  
19.
  • Cederlund, Harald, et al. (författare)
  • Soil carbon quality and nitrogen fertilization structure bacterial communities with predictable responses of major bacterial phyla
  • 2014
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 84, s. 62-68
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural practices affect the soil ecosystem in multiple ways and the soil microbial communities represent an integrated and dynamic measure of soil status. Our aim was to test whether the soil bacterial community and the relative abundance of major bacterial phyla responded predictably to long-term organic amendments representing different carbon qualities (peat and straw) in combination with nitrogen fertilization levels and if certain bacterial groups were indicative of specific treatments. We hypothesized that the long-term treatments had created distinctly different ecological niches for soil bacteria, suitable for either fast-growing copiotrophic bacteria, or slow-growing oligotrophic bacteria. Based on terminal-restriction fragment length polymorphism of the 16S rRNA genes from the total soil bacterial community and taxa-specific quantitative real-time PCR of seven different groups, all treatments significantly affected the community structure, but nitrogen fertilization was the most important driver for changes in the relative abundances of the studied taxa. According to an indicator species analysis, the changes were largely explained by the decline in the relative abundances of Acidobacteria, Gemmatimonadetes and Verrucomicrobia with nitrogen fertilization. Conditions more favourable for copiotrophic life strategies were indicated in these plots by the decreased metabolic quotient, i.e. the ratio between basal respiration rate and soil biomass. Apart from the Alphaproteobacteria that were significantly associated with peat, no taxa were indicative of organic amendment in general. However, several significant indicators of both peat and straw were identified among the terminal restriction fragments suggesting that changes induced by the organic amendments were mainly manifested at a lower taxonomical level. Our findings strengthen the proposition that certain higher bacterial taxa adapt in an ecologically coherent way in response to changes induced by fertilization. (C) 2014 Elsevier B.V. All rights reserved.
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20.
  • De Marco, Anna, et al. (författare)
  • Shifts in soil chemical and microbial properties across forest chronosequence on recent volcanic deposits
  • 2021
  • Ingår i: Agriculture, Ecosystems & Environment. Applied Soil Ecology. - : Elsevier. - 0929-1393 .- 1873-0272. ; 161
  • Tidskriftsartikel (refereegranskat)abstract
    • Afforestation of new unconsolidated volcanic deposits is a practice used to stabilize barren areas and enhance the accumulation of organic matter in the developing soil. Changes in soil carbon (C) and nitrogen (N) pools, including the soluble and microbial fractions, within the first decades since afforestation have been poorly investigated. Therefore the objective of the present study was to investigate how key C and N pools vary in litter and soil of four forests planted on barren volcanic deposits from recent Mount Vesuvius eruptions. We examined three forest stands (40, 70 and 100 years old) afforested with Stone pine (Pinus pinea L.) and a 40-year old forest of Black pine (Pinus nigra Arn.). As a baseline of C and N pools prior to afforestation, data from treeless sites were included in the study. Both the inputs with litter fall and soil C and N stocks increased with forest age in the Stone pine stands. In the mineral soil, C concentration per gram soil dry weight and C:N ratio increased with age from treeless sites to the oldest forest. Microbial biomass C and fungal biomass as a fraction of organic carbon (OC) and respiration per unit OC (an index of organic matter mineralization potential) decreased significantly with stand age. The results suggest that a main driver of C accumulation in the mineral soil is the decline with increasing stand age of the microbial fraction of organic matter and its activity. The comparison between the two pine species revealed that litter production was more abundant in the Black pine than in the even-aged, 40-year-old, Stone pine stand; moreover Black pine litter was more acidic and had a higher stable residue than Stone pine litter. Therefore a different pattern of C sequestration occurs with a higher C stock in the organic layers and a lower C stock in the mineral soil of Black pine compared to Stone pine.
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21.
  • Dimitrova Mårtensson, Linda-Maria (författare)
  • Perennial cereal grain cultivation: Implication on soil organic matter and related soil microbial parameters
  • 2022
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 174
  • Tidskriftsartikel (refereegranskat)abstract
    • Novel perennial grains in agriculture have the potential of providing soil ecosystem services and boosting plant-soil microbial relationships via increasing soil organic matter (SOM). Hence, we evaluated the implication of perennial intermediate wheatgrass agroecosystems (+/− alfalfa intercrop) in contrast to organic and conventional rotation systems on SOM and related soil microbial parameters. Soil samples were obtained from perennial intermediate wheatgrass (IWG), sole (IWG-SC) or intercropped with alfalfa (IWG-IC), as well as organic (ORG-A) and conventional (CON-A) rotation systems of annual wheat. Soil samples were taken in two depths (0–30 cm and 30–60 cm) and analyzed for total and fractionated soil organic C (SOC), microbial biomass C and N (MBC and MBN), basal microbial respiration (Rb), potential enzyme activities related to C and N cycling (Cellobiohydrolase (CBH), Leucine-aminopeptidase (LAP)), and abundance of functional genes related to N cycling (amoA, nifH) and 16S rRNA genes. Despite the lack of fertilization in the IWG systems, SOC concentration and the amount of C in the particulate organic matter were higher in the 30–60 cm depth of IWG systems than ORG-A and CON-A. Higher MBN and LAP activities were observed in the 0–30 cm depth of ORG-A than both IWG and CON-A. Mass specific CBH activities and metabolic quotient qCO2 were lower in the 30–60 cm depth of IWG systems, implying reduced C losses and high C use efficiency in these systems. Similarly, we observed higher amounts of 16S rRNA in the 30–60 cm depth of IWGs than ORG-A and CON-A. Hence, IWG systems increased SOC and microbial biomass and activities in the 30–60 cm depth than ORG-A and CON-A. However, the more diverse IWG (+ alfalfa intercrop) did not increase microbial biomass and activities than IWG monoculture. Our study provides a reflection of how perennial grain agroecosystems, in conjunction with organic rotation systems, induce a positive influence on SOC and microbial activities than CON-A. It further suggested that perennial grain cultivation goes beyond the reach of organic farming dominated by annual crops to induce SOC and support relevant soil microbial functions in subsoils.
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22.
  • 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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23.
  • 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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24.
  • 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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25.
  • 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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26.
  • Friberg, Hanna, et al. (författare)
  • Contribution of anecic and epigeic earthworms to biological control of Fusarium graminearum in wheat straw
  • 2021
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 166
  • Tidskriftsartikel (refereegranskat)abstract
    • Earthworms have proved to contribute to plant health indirectly, by improvement of soil physical and chemical properties, as well as directly, through suppression of plant pathogens. Fusarium Head Blight, caused primarily by Fusarium graminearum, is one of the most important cereal diseases, with severe detrimental effects on yield and grain quality worldwide, and significant effect on grain safety due to the accumulation of mycotoxins produced by the fungus. Earthworms could reduce the residue-borne inoculum density of F. graminearum through different mechanisms, including direct competition by residue consumption, growth inhibition caused by the earthworm coelomic fluid, mechanical disruption of fungal hyphae, and burying crop residue which reduce the chances for the fungus to release spores for head infection. Thus, the aim of this study was to assess the effects of anecic and epigeic earthworms on wheat straw and on F. graminearum inoculum. For this, PVC cylinders (microcosms 14.5 cm diameter, 30 cm height) were filled with moist soil mix, wheat straw was evenly distributed on the soil surface (inoculated with Fusarium, soil microorganisms or sterile) and three earthworm species (Aporrectodea longa, Lumbricus rubellus or Lumbricus terrestris) were tested. Since the response of earthworms may change according to conditions of soil moisture and food availability, two different experiments were arranged. The first Experiment represented a sub-optimal situation for earthworms regarding soil moisture and feeding conditions, which was obtained by scarce watering of the microcosms with a consequent decrease in soil water content during incubation, and by not adding cow manure as supplementary food source. In the second experiment, soil was enriched with cow manure as feed for the earthworms and soil moisture was maintained above 25%. Results from qPCR analysis revealed that F. graminearum inoculum on straw was reduced to undetectable amounts by L. rubellus and A. longa when the feeding conditions were limited, while no significant differences compared with the control without earthworms were found when earthworms had high food availability (alpha = 0.05). Straw coverage on soil surface was reduced by L. rubellus (epigeic) in both experiments (p < 0.0001), while A. longa (anecic) just did so under optimal conditions. L. terrestris (anecic), only tested under optimal conditions, reduced soil cover significantly more than the other two species (p < 0.0001). Negative effect of this fungus was not observed on the studied earthworms. Both anecic and epigeic earthworms tested showed potential to contribute to biological control of F. graminearum in wheat straw. This control may occur by reducing straw on surface, reducing the pathogen inoculum on straw, or both, depending on the environmental conditions and their response according to their ecological group and species. The possibilities to optimize earthworm capacity for biological control of fungal diseases in practical agriculture, under changing weather and organic matter supply conditions, are discussed.
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27.
  • 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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28.
  • 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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29.
  • 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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30.
  • 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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31.
  • 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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32.
  • Hedwall, Per-Ola, et al. (författare)
  • Forest density and edge effects on soil microbial communities in deciduous forests across Europe
  • 2022
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 179
  • Tidskriftsartikel (refereegranskat)abstract
    • Forest fragmentation increases the proportion of edge area and this, in turn, induces changes in forest structure, species composition and microclimate. These factors are also strongly determined by the forest management regime. Although the interactive effects of edges and density on forest plant communities have been extensively studied, little is known about the response of the belowground communities. Here we investigated the variation of soil microbiota in 45 deciduous broadleaved forests along a latitudinal gradient from Italy to Norway at a continental scale across Europe. Phospholipid fatty acid (PLFA) and neutral lipid fatty acid (NLFA) were used to map the microbial community in the forest edge and interior across three forest densities (dense, intermediate, open forest). Microbial community composition was only affected by forest edge effects and not by forest density. We did not find any interaction effects between forest density and distance-to-edge. Arbuscular mycorrhizal fungi (AMF) were significantly more abundant in edges and Gram-negative bacteria more abundant in interiors, respectively. The microbial community composition was closely related to soil pH, soil potassium and nitrogen, texture (percent sand) and soil temperature. Soil pH was positively correlated with the saprotrophic fungi and potassium was positively correlated with Gram-negative bacteria but negatively correlated with Actinobacteria. In sum, we reveal the notable effects of forest edges on the soil AMF abundance. This result indicated that AMF could possess a stronger affinity with species growing in the edges, which may help to improve plant perfor-mance under hostile conditions herein.
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33.
  • 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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34.
  • Hodkinson, ID, et al. (författare)
  • Functional ecology of soil organisms in tundra ecosystems: towards the future
  • 1999
  • Ingår i: APPLIED SOIL ECOLOGY. - : ELSEVIER SCIENCE BV. - 0929-1393. ; 11:2-3, s. 111-126
  • Tidskriftsartikel (refereegranskat)abstract
    • The need to understand the functional linkages between Arctic/alpine soil communities and the major soil processes is stressed. Soil organisms are classified into broad functional groups and it is suggested that the functional success of any organism can
  •  
35.
  • 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.
  •  
36.
  • 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.
  •  
37.
  • 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.
  •  
38.
  • Jensen, Erik Steen (författare)
  • Effects of digestate from anaerobically digested cattle slurry and plant materials on soil microbial community and emission of CO2 and N2O
  • 2013
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 63, s. 36-44
  • Tidskriftsartikel (refereegranskat)abstract
    • Anaerobic digestion of animal manure and crop residues may be employed to produce biogas as a climate-neutral source of energy and to recycle plant nutrients as fertilizers. However, especially organic farmers are concerned that fertilizing with the digestates may impact the soil microbiota and fertility because they contain more mineral nitrogen (N) and less organic carbon (C) than the non-digested input materials (e.g. raw animal slurry or fresh plant residues). Hence, an incubation study was performed where (1) water, (2) raw cattle slurry, (3) anaerobically digested cattle slurry/maize, (4) anaerobically digested cattle slurry/grass-clover, or (5) fresh grass-clover was applied to soil at arable realistic rates. Experimental unites were sequentially sampled destructively after 1, 3 and 9 days of incubation and the soil assayed for content of mineral N, available organic C, emission of CO2 and N2O, microbial phospholipid fatty acids (biomass and community composition) and catabolic response profiling (fiinctional diversity). Fertilizing with the anaerobically digested materials increased the soil concentration of NO3- ca. 30-40% compared to when raw cattle slurry was applied. Grass-clover contributed with four times more readily degradable organic C than the other materials, causing an increased microbial biomass which depleted the soil for mineral N and probably also O-2. Consequently, grass-clover also caused a 10 times increase in emissions of CO2 and N2O greenhouse gasses compared to any of the other treatments during the 9 days. Regarding microbial community composition, grass-clover induced the largest changes in microbial diversity measures compared to the controls, where raw cattle slurry and the two anaerobically digested materials (cattle slurry/maize, cattle slurry/grass-clover) only induced minor and transient changes. (C) 2012 Elsevier B.V. All rights reserved.
  •  
39.
  • Kardol, Paul (författare)
  • Climate change effects on soil microarthropod abundance and community structure
  • 2011
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 47, s. 37-44
  • Tidskriftsartikel (refereegranskat)abstract
    • Our data demonstrate how simultaneously acting climate change factors can affect the structure of soil microarthropod communities in old-field ecosystems. Overall, changes in soil moisture content, either as direct effect of changes in precipitation or as indirect effect of warming or elevated [CO2], had a larger impact on microarthropod communities than did the direct effects of the warming and elevated [CO2] treatments. Moisture-induced shifts in soil microarthropod abundance and community composition may have important impacts on ecosystem functions, such as decomposition, under future climatic change. (c) 2010 Elsevier B.V. All rights reserved.
  •  
40.
  • Kardol, Paul (författare)
  • Lycium barbarum L. (goji berry) monocropping causes microbial diversity loss and induces Fusarium spp. enrichment at distinct soil layers
  • 2021
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 168
  • Tidskriftsartikel (refereegranskat)abstract
    • The high salt-and drought-tolerance of Lycium barbarum L. (goji berry) makes the plant suitable for cultivation in the arid and semi-arid regions of northwest China. However, monocropping of L. barbarum has caused severe issues, including increasing plant disease incidents and declining goji berry productivity. The negative impacts of L. barbarum monocropping on the soil health over time remain unclear. We investigated the temporal shifts in soil properties and microbial community diversity in the top (0-20 cm) and subsoils (20-40 cm) of L. barbarum fields across a 20-year age sequence and the adjacent control fields at two independent research sites in Ningxia, China. Our results show that L. barbarum monocropping leads to accumulation of total organic C, N, P, and available N stocks, but simultaneously caused secondary soil salinization and soil pH declination. The community alpha-diversity indices and the dissimilarities in community compositions of bacteria and fungi generally decline with the increase in stand age at both soil depths. Co-occurrence analysis found a decreased complexity of network structure with stand development, indicating that monocropping would profoundly disrupt the potential interactions among soil microbes. The phytopathogenic fungi Fusarium spp. progressively prevailed in soils of L. barbarum fields. The structural equation modeling further demonstrates that the variation in bacterial community composition directly explained the increase in the absolute abundance of Fusarium spp. The results infer an essential role of soil bacterial assemblages in the biocontrol of Fusarium wilt of L. barbarum under mono cropping. Together, our results suggest that secondary soil salinization, loss of soil microbial diversity, and buildup of fungal phytopathogens, particularly in subsoils, are major threats to the soil health of L. barbarum field. An in-depth understanding of these threats to soil quality could help develop sustainable cropping management for L. barbarum.
  •  
41.
  • 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.
  •  
42.
  • Krab, Eveline J., et al. (författare)
  • Northern peatland Collembola communities unaffected by three summers of simulated extreme precipitation
  • 2014
  • Ingår i: Agriculture, Ecosystems & Environment. Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 79, s. 70-76
  • Tidskriftsartikel (refereegranskat)abstract
    • Extreme climate events are observed and predicted to increase in frequency and duration in high-latitudeecosystems as a result of global climate change. This includes extreme precipitation events, which maydirectly impact on belowground food webs and ecosystem functioning by their physical impacts and byaltering local soil moisture conditions.We assessed responses of the Collembola community in a northern Sphagnum fuscum-dominatedombrotrophic peatland to three years of experimentally increased occurrence of extreme precipitationevents. Annual summer precipitation was doubled (an increase of 200 mm) by 16 simulated extremerain events within the three months growing season, where on each occasion 12.5 mm of rain was addedwithin a few minutes. Despite this high frequency and intensity of the rain events, no shifts in Collemboladensity, relative species abundances and community weighted means of three relevant traits (moisturepreference, vertical distribution and body size) were observed. This strongly suggests that the peatlandCollembola community is unaffected by the physical impacts of extreme precipitation and the short-termvariability in moisture conditions. The lack of response is most likely reinforced by the fact that extremeprecipitation events do not seem to alter longer-term soil moisture conditions in the peat layers inhabitedby soil fauna.This study adds evidence to the observation that the biotic components of northern ombrotrophicpeatlands are hardly responsive to an increase in extreme summer precipitation events. Given the importance of these ecosystems for the global C balance, these findings significantly contribute to the currentknowledge of the ecological impact of future climate scenarios. (C) 2014 Elsevier B.V. All rights reserved.
  •  
43.
  • 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.
  •  
44.
  • Lagerlöf, Jan, et al. (författare)
  • Land-use intensification and agroforestry in the Kenyan highland: Impacts on soil microbial community composition and functional capacity
  • 2014
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 82, s. 93-99
  • Tidskriftsartikel (refereegranskat)abstract
    • This study investigates microbial communities in soil from sites under different land use in Kenya. We sampled natural forest, forest plantations, agricultural fields of agroforestry farms, agricultural fields with traditional farming and eroded soil on the slopes of Mount Elgon, Kenya. We hypothesised that microbial decomposition capacity, biomass and diversity (1) decreases with intensified cultivation; and (2) can be restored by soil and land management in agroforestry. Functional capacity of soil microbial communities was estimated by degradation of 31 substrates on Biolog EcoPlates (TM). Microbial community composition and biomass were characterised by phospholipid fatty acid (PLFA) and microbial C and N analyses. All 31 substrates were metabolised in all studied soil types, i.e. functional diversity did not differ. However, both the substrate utilisation rates and the microbial biomass decreased with intensification of land use, and the biomass was positively correlated with organic matter content. Multivariate analysis of PLFA and Biolog EcoPlate (TM) data showed clear differences between land uses, also indicated by different relative abundance of PLFA markers for certain microorganism groups. In conclusion, our results show that vegetation and land use control the substrate utilisation capacity and microbial community composition and that functional capacity of depleted soils can be restored by active soil management, e. g. forest plantation. However, although 20-30 years of agroforestry farming practises did result in improved soil microbiological and chemical conditions of agricultural soil as compared to traditional agricultural fields, the change was not statistically significant. (C) 2014 Elsevier B. V. All rights reserved.
  •  
45.
  • Lagerlöf, Jan, et al. (författare)
  • Potential side effects of biocontrol and plant-growth promoting Bacillus amyloliquefaciens bacteria on earthworms
  • 2015
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 96, s. 159-164
  • Tidskriftsartikel (refereegranskat)abstract
    • After 1-2 months, survival, growth and reproduction of the earthworms were recorded. We found no effect of the treatments as compared to control without BA amendments. We conclude that the use of high doses of BA with concentrations at the same magnitude as maximally expected when the bacteria are used as PGPR and BCA, is not harmful to the soil dwelling earthworms tested in this project. Further studies of the ecological effects of PGPR and BCA bacteria on other non-target soil organisms are encouraged. The development of sustainable agricultural systems, where ecosystem services are optimized, has to be aided by a deeper knowledge of the combined effect of bacteria and earthworms on the promotion of plant health. (C) 2015 Elsevier B.V. All rights reserved.
  •  
46.
  • 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.
  •  
47.
  • Löbmann, Michael, et al. (författare)
  • The occurrence of pathogen suppressive soils in Sweden in relation soil biota, soil properties, and farming practices
  • 2016
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 107, s. 57-65
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite more than 50 years of research and their great potential for sustainable pest management, pathogen suppressive soils remain poorly understood. We conducted a study on suppression of root rot disease symptoms associated with Pythium ultimum in untreated and heat-sterilized soil from ten southern Swedish farms with six different cropping and management regimes. Physical and chemical soil properties, soil nematodes belonging to different trophic guilds, and the predominant soil oomycetes were analyzed for their potential as indicators of soil suppressiveness. Six of the ten sampled soils were suppressive to P. ultimum disease symptoms. Suppressive or conducive properties of the soils from sites with permanent soil cover were related to the presence of live soil biota, while soils from sites with interrupted soil cover had suppressive or conducive effects unrelated to live soil biota. In soils with biologically conducive effects, soils had high or low cation nutrient content, while biologically suppressive soils had intermediate nutrient levels. No relationship was found between disease symptoms and the soil nematode trophic community or the predominant soil oomycetes. Permanent soil cover and a balanced nutrient supply were correlated with biologically suppressive effects on P. ultimum disease symptoms. (C) 2016 The Authors. Published by Elsevier B.V.
  •  
48.
  • 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.
  •  
49.
  • Malmström, Anna, et al. (författare)
  • Do burned areas recover from inside? An experiment with soil fauna in a heterogeneous landscape
  • 2012
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 59, s. 73-86
  • Tidskriftsartikel (refereegranskat)abstract
    • The post-fire soil faunal communities are formed both by animals having survived the fire and by colonizers from the surrounding landscape. The relative impact of these processes is largely affected by fire intensity. However, with the same fire intensity, the severity of the fire and, thus, the survival of soil animals could vary depending on environmental heterogeneity. We hypothesized that much fewer soil animals would survive the same fire intensity on shallow, dry soils than on deep, moist soils. To clarify the impact of soil depth and moisture on animal survival after fire, we conducted a burning experiment in the laboratory. Soil samples containing indigenous populations of soil fauna were taken along two transects from the top, slope and foot of two respective rocky outcrops within a mixed coniferous forest in Central Sweden. Half of the samples were burnt and half were left unburnt. Burning depth varied between 24 mm (soils from the top of the gradient) to 12 mm (slope and foot soils) indicating a difference in flammability. The proportion of animals surviving fire seemed to be fairly independent of burning depth (42 to 62% survival rate). Contribution of eggs which survived fire in the soil to the overall animal abundance restoration was negligible (1–3%). A multi-trophic approach resulted in different sensitivity estimates to artificial burning of various parameters. Abundance and biomass of all fauna groups studied was more sensitive to fire than species richness. Collembolans and macrofauna predators were the groups most tolerant to fire, while oribatid mites and macrofaunal detritivores showed higher mortality after the fire treatment. Despite a more pronounced alteration of the components of soil food-web by burning in the lowland Sphagnum plots, they may be important as refugia, especially for more slowly moving soil-dwelling macro- and microarthropods
  •  
50.
  • Malmström, Anna, et al. (författare)
  • Dynamics of soil meso- and macrofauna during a 5-year period after clear-cut burning in a boreal forest
  • 2009
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 43, s. 61-74
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to determine effects of clear-cutting and prescribed clear-cut burning on the abundance and diversity of soil meso- and macrofauna during the early (0-5 years) recovery/recolonisation phase. A 115-year-old stand of mixed Pinus sylvestris and Picea abies in central Sweden was clear-cut in March 1999. Injune 1999, two plots on the clear-cut were burnt and two plots were left unburnt according to an experimental design with two blocks. Two plots of adjacent uncut forest were used as controls. The burning combusted the ground vegetation and the upper half of the 6-cm thick organic layer. In comparison with the unburnt clear-cut, burning decreased the abundances of Collembola, Protura, Mesostigmata, Araneae and Diptera larvae throughout the 5-year period, whereas Enchytraeidae, Lumbricidae, Oribatida, Prostigmata, Astigmata and Tardigrada decreased immediately after the fire but showed tendencies of recovery. Burning also decreased species richness. The majority of the species still absent after 5 years was surface-living species. Even animals with good ability to disperse (Diptera, Coleoptera and Araneae) had not recovered, which indicates a change of habitat or lack of food. Clear-cut burning was particularly detrimental to fungivores and predators, whereas microbidetritivores and herbivores were less affected. Prescribed burning, which is considered to increase aboveground biodiversity, dramatically reduced the soil fauna species richness for at least 5 years and did not add any species to those already present in the forest or clear-cut. (C) 2009 Elsevier B.V. All rights reserved.
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