Antibiotic resistance reservoirs : the cases of sponge and human gut microbiota
Versluis, Dennis - \ 2016
Wageningen University. Promotor(en): Hauke Smidt, co-promotor(en): Mark van Passel; Detmer Sipkema. - Wageningen : Wageningen University - ISBN 9789462579057 - 197
antibiotic resistance - reservoirs - intestinal microorganisms - luffa - forest soils - sediment - escherichia coli - penicillium - faecal examination - antibioticaresistentie - reservoirs - darmmicro-organismen - luffa - bosgronden - sediment - escherichia coli - penicillium - fecesonderzoek
One of the major threats to human health in the 21st century is the emergence of pathogenic bacteria that are resistant to multiple antibiotics, thereby limiting treatment options. An important route through which pathogens become resistant is via acquisition of resistance genes from environmental and human-associated bacteria. Yet, it is poorly understood to what extent and by what mechanisms these so-called reservoirs contribute to emerging resistance. Therefore, the work described in this thesis focussed on generating novel insights into different niches as sources of resistance, with a particular focus on the human gut microbiota as well as on microbial communities associated with marine sponges, especially because the latter have been described as one of the richest sources of bioactive secondary metabolites, including a broad range of antimicrobials. Cultivation-based methods were complemented with culture-independent approaches in order to study bacterial taxa that are not readily cultivated.
Using metatranscriptomics it was found that clinically relevant antibiotic resistance genes are expressed in a broad range of environmental niches including human, mouse and pig gut microbiota, sea bacterioplankton, a marine sponge, forest soil and sub-seafloor sediment. The diversity of resistance gene transcripts differed greatly per niche indicating that the environment contains a rich reservoir of functional resistance that could be accessible by pathogens. Even though resistance gene expression might be linked to the presence of natural antibiotics, we did not detect expression of the corresponding secondary metabolite biosynthesis clusters.
Thirty-one antibiotic-resistant bacteria, amongst which three belonging to potentially novel Flavobacteriaceae spp., were isolated from the Mediterranean sponges Aplysina aerophoba, Corticium candelabrum and Petrosia ficiformis. Isolates were identified in a high throughput manner by double-barcoded 16S rRNA gene amplicon sequencing. Furthermore, analysis of sponge tissue-derived bacterial biomass growing on agar media showed that many novel bacterial taxa can still be isolated by conventional cultivation methods. Genomic DNA from the 31 antibiotic resistant bacteria was interrogated with respect to the presence of active resistance genes by functional metagenomics. In addition, we also screened metagenomic libraries prepared from DNA directly isolated from sponge tissue in order to circumvent the need for cultivation. In total, 37 unique resistance genes were identified, and the predicted gene products of 15 of these shared <90% amino acid identity with known gene products. One resistance gene (blaPSV-1), which was classified into a new β-lactamase family, was found to be exclusive to the marine specific genus Pseudovibrio. These findings raised questions as to the functional roles of these genes in sponges, but more importantly, the functionality of these genes in E. coli shows that they can potentially be harnessed by phylogenetically distinct bacteria in other environments, including human pathogens. As such, it is a wake-up call as to the significance of marine resistance reservoirs.
Pseudovibrio, a genus of α-Proteobacteria, was studied in more detail by comparative genomics as it comprises bacteria that potentially play a role as sponge symbionts and marine hubs of antibiotics resistance. Based on gene content, members of the genus Pseudovibrio were found to cluster by sponge sampling location indicating geographic speciation. Furthermore, Pseudovibrio spp. isolated from sponges near the Spanish coast clustered by sponge, suggesting host-specific colonization or adaptation. Strong support for Pseudovibrio spp. forming symbiotic relations with sponges came from the presence of a plethora of (predicted) conserved symbiosis-related functions in their genomes.
A final study aimed to isolate novel antibiotic resistant reservoir species from the human gut microbiota using a targeted approach. Faecal samples from hospitalized patients that received Selective Digestive Decontamination (SDD), a prophylactic treatment with a cocktail of different antibiotics (tobramycin, polymyxin E, amphotericin B and cefotaxime), were inoculated anaerobically on agar media, after which bacterial biomass was analysed by 16S rRNA gene amplicon sequencing. Six novel taxa were identified that, based on their growth on media supplemented with the SDD antibiotics, could serve as clinically relevant reservoirs of antibiotic resistance. For one of these six taxa a member was obtained in pure culture by targeted isolation. The abundance of antibiotic resistant uncultivated taxa in the human gut microbiota warrants further research as to their potential roles in resistance dissemination.
In conclusion, this thesis provides deeper insights into different environmental niches as reservoirs of antibiotic resistance. The results can serve to prime and inspire future research.
Terug naar de basis
Willems, Arno ; Schreppers, Harrie ; Jans, Rino ; Klingen, Simon ; Ouden, J. den; Schoonderwoerd, Henny ; Wijdeven, Sander ; Staak, Erik van der - \ 2016
Vakblad Natuur Bos Landschap 13 (2016)127. - ISSN 1572-7610 - p. 40 - 41.
bosbeheer - houtachtige planten - duurzaamheid (sustainability) - bosgronden - bodemuitputting - bosecologie - voedingsstoffenbalans - verzuring - bodemverdichting - mechanisatie - forest administration - woody plants - sustainability - forest soils - soil exhaustion - forest ecology - nutrient balance - acidification - soil compaction - mechanization
Als bosbeheerders gaan we er prat op dat we het begrip duurzaamheid hebben uitgevonden. Dat is inderdaad iets om trots op te zijn en bewijst dat we als sector gewend zijn ver vooruit te kijken en te denken. Het is echter de vraag of we onze bossen nog wel volgens de principes van duurzaamheid beheren. Met name over de mogelijke uitputting van de bodem en de invloed van de exploitatie op de bodem bestaan veel vragen waarvan de antwoorden niet voor het oprapen liggen. Op 17 mei 2016 ging de Studiekring van de KNBV terug naar de basis: de bosbodem.
Legacies of Amazonian dark earths on forest composition, structure and dynamics
Quintero Vallejo, E.M. - \ 2015
Wageningen University. Promotor(en): Frans Bongers; Lourens Poorter, co-promotor(en): Marielos Pena Claros; T. Toledo. - Wageningen : Wageningen University - ISBN 9789462574267 - 168
bossen - bosgronden - bosdynamiek - bodemvruchtbaarheid - botanische samenstelling - soortensamenstelling - plantengemeenschappen - amazonia - bolivia - forests - forest soils - forest dynamics - soil fertility - botanical composition - species composition - plant communities - amazonia - bolivia
Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation, expansion and retreat of human populations have not always been obvious in those ecosystems, leaving sometimes weak and overlooked imprints in the landscape. An example of one of these inconspicuous alterations are the modifications in the soil known as Amazonian Dark Earths (ADE) or ‘terra preta’ (black earth in Portuguese), which are the product of the accumulation of residuals from permanent or semi-permanent human inhabitation. They are named after the black color of the soils, which is a consequence of the accumulation of charcoal pieces and organic matter in the soil. These soils also contain higher levels of phosphorous, calcium (mainly originated from bone residuals), and nitrogen that increase fertility of the naturally poor soils, thus favouring agricultural practices. Amazonian Dark Earths are distributed in Brazil, Bolivia, Colombia, and Peru, and it is estimated that they could occupy 3% of the area of the Amazon basin.
With the decrease in human population in the Americas after the encounter with European colonists, sites where ADE had been formed were abandoned and the vegetation recovered. So far, the effects of ADE on old growth forest had not been widely examined and we are just starting to understand the consequences of past human inhabitation on forest composition and structure. In my thesis, I evaluated the effects of ADE on the forest that has re-grown after abandonment by indigenous people in the La Chonta forest, situated at the southern edge of the Amazon basin, in Bolivia. First, I assessed the magnitude of the changes in the soil as a consequence of human occupation. Then, I studied how soil changes affected plant species composition in the forest understory, forest structure and forest dynamics, and finally I determined how seedlings of tree species respond to anthropogenic changes in soil properties.
Detailed information on soil characteristics and its heterogeneity in the landscape is needed to evaluate the effects of soil on the vegetation. Soil heterogeneity in some sites in the Amazon basin can be increased by the presence of ADE. Therefore, I did detailed soil surveys that allowed me to understand the relationship between past human occupation and alteration in the concentration of soil nutrients. I found that natural soils in the southern Amazonian forest are more fertile than their Central and Eastern Amazon counterparts. Past human presence in the area resulted in soil enrichment, due to increases in the concentration of phosphorus, calcium, potassium, and increases in soil pH. Thus, with this information I could test specific hypothesis about the effects of soil fertility on the vegetation that occurs in these sites.
In the Amazonian forest in general, soil characteristics influences the composition of understory angiosperm herbs, ferns and palm species. Thus, increases in soil fertility in ADE could affect the distribution of understory angiosperm herbs, ferns and palm species. I evaluated the effect of ADE on composition, richness and abundance of understory species (ferns, angiosperm herbs, and palms). I correlated soil variables associated with ADE, such as Ca, P, and soil pH, with species composition, richness and abundance. I found that the presence of ADE created a gradient in soil nutrients and pH, which changed the composition of understory species, especially of ferns and palms. Additionally, the higher nutrient concentration and the more neutral pH on ADE soils were associated with a decrease in the richness of fern species. I therefore conclude that the current composition of the understory community in La Chonta is a reflection of past human modification of the soil.
Soil heterogeneity drives forest structure and forest dynamics across the Amazon region, but at a local scale the role of soils on forest dynamics is not well understood. The study of Amazonian Dark Earths (ADE) opens an opportunity to test how increases in soil fertility could affect forest structure and dynamics at local scales. I evaluated the effect of ADE on forest attributes, such standing basal area, tree liana infestation and successional composition, defined by the relative presence of pioneers, to shade tolerant species in the forest. I also evaluated the effect of ADE on individual components of forest dynamics: basal area growth, recruitment, and mortality. Surprisingly, I found that these fertile ADE affected only few forest attributes and components of forest dynamics. Soil pH was one of the edaphic variables that significantly explained forest structure and dynamics. A higher soil pH increased recruitment of intermediate-sized trees (with stem diameter between 20 and 40 cm) and decreased mortality of large trees (stem diameter > 40 cm). The most important effect of pH, however, was on initial basal area and successional composition, which directly affected growth in basal area of intermediate-sized trees.
Increases in soil nutrients can drive plant responses promoting higher growth rates and lower mortality. Plants respond to soil nutrient availability through a suite of traits, by adjusting their biomass allocation patterns, morphology, tissue chemistry and physiology, which allow them successful establishment and regeneration. The higher amount of nutrients found on ADE compared to natural soils could improve the growth of tropical tree species. I studied the effect of ADE on seedling growth, morphology and physiology in a greenhouse experiment with seedlings of 17 tree species from La Chonta. I found that seedlings did not invest more in roots in non-ADE (to take up scarce soil resources) but they invested in leaves and leaf area in ADE (to enhance light capture), although this did not lead to faster growth rate. Tree species responded differently to an increase in soil Ca concentration, which was 2.4 times higher in ADE than in non-ADE soils. Some species seemed to suffer from Ca toxicity as indicated by higher seedling mortality on ADE; others suffered from nutrient imbalance; whereas other species increased their leaf Ca, P and N concentrations in ADE. Only for this latter group of nutrient accumulators, there was a positive relationship between leaf Ca concentration and the growth rates of seedlings. Contrary to expectations, ADE did not lead to increased seedling growth. The ability of plants to colonize patches of ADE might depend on plant responses to increased soil Ca and their capacity to regulate internal tissue calcium to balance nutrition.
In summary, in this southern Amazon forest the increased soil nutrient concentrations are a legacy of the humans that inhabited the area. This nutrient addition caused changes in understory species composition and decreased fern species richness and had modest effects on forest structure and dynamics. Increases in nutrients, specifically Ca, can cause positive and negative responses of tree species, resulting in potentially long term effects on the tree species composition of the forest.
Methane, Carbon Dioxide and Nitrous Oxide Fluxes in Soil Profile under a Winter Wheat-Summer Maize Rotation in the North China Plain
Wang, Y.Y. ; Hu, C.S. ; Ming, H. ; Oenema, O. ; Schaefer, D.A. ; Dong, W.X. ; Zhang, Y.M. ; Li, X.X. - \ 2014
PLoS ONE 9 (2014)6. - ISSN 1932-6203
forest soils - co2 efflux - gas emissions - n2o fluxes - ch4 - respiration - temperature - mitigation - diffusion - slurry
The production and consumption of the greenhouse gases (GHGs) methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) in soil profile are poorly understood. This work sought to quantify the GHG production and consumption at seven depths (0-30, 30-60, 60-90, 90-150, 150-200, 200-250 and 250-300 cm) in a long-term field experiment with a winter wheat-summer maize rotation system, and four N application rates (0; 200; 400 and 600 kg N ha(-1) year(-1)) in the North China Plain. The gas samples were taken twice a week and analyzed by gas chromatography. GHG production and consumption in soil layers were inferred using Fick's law. Results showed nitrogen application significantly increased N2O fluxes in soil down to 90 cm but did not affect CH4 and CO2 fluxes. Soil moisture played an important role in soil profile GHG fluxes; both CH4 consumption and CO2 fluxes in and from soil tended to decrease with increasing soil water filled pore space (WFPS). The top 0-60 cm of soil was a sink of atmospheric CH4, and a source of both CO2 and N2O, more than 90% of the annual cumulative GHG fluxes originated at depths shallower than 90 cm; the subsoil (>90 cm) was not a major source or sink of GHG, rather it acted as a 'reservoir'. This study provides quantitative evidence for the production and consumption of CH4, CO2 and N2O in the soil profile.
Production-ecological modelling explains the difference between potential soil N mineralisation and actual herbage N uptake
Rashid, M.I. ; Goede, R.G.M. de; Brussaard, L. ; Bloem, J. ; Lantinga, E.A. - \ 2014
Applied Soil Ecology 84 (2014). - ISSN 0929-1393 - p. 83 - 92.
winter-wheat fields - nitrogen mineralization - organic-matter - food webs - grassland soils - forest soils - community - manure - earthworms - management
We studied two different grassland fertiliser management regimes on sand and peat soils: above-ground application of a combination of organic N-rich slurry manure and solid cattle manure (SCM) vs. slit-injected, mineral N-rich slurry manure, whether or not supplemented with chemical fertiliser (non-SCM). Measurements of field N mineralisation as estimated from herbage N uptake in unfertilised plots were compared with (i) potential N mineralisation as determined from a standard laboratory soil incubation, (ii) the contribution of groups of soil organisms to N mineralisation based on production-ecological model calculations, and (iii) N mineralisation calculated according to the Dutch fertilisation recommendation for grasslands. Density and biomass of soil biota (bacteria, fungi, enchytraeids, microarthropods and earthworms) as well as net plant N-uptake were higher in the SCM input grasslands compared to the non-SCM input grasslands. The currently used method in Dutch fertilisation recommendations underestimated actual soil N supply capacity by, on average, 102 kg N ha-1 (202 vs. 304 kg ha-1 = 34%). The summed production-ecological model estimate for N mineralisation by bacteria, fungi, protozoa, and enchytraeids was 87–120% of the measured potential soil N mineralisation. Adding the modelled N mineralisation by earthworms to potential soil N mineralisation explained 98–107% of the measured herbage N uptake from soil. For all grasslands and soil biota groups together, the model estimated 105% of the measured net herbage N uptake from soil. Soil biota production-ecological modelling is a powerful tool to understand and predict N uptake in grassland, reflecting the effects of previous manure management and soil type. The results show that combining production ecological modelling to predict N supply with existing soil N tests using aerobic incubation methods, can add to a scientifically based improvement of the N fertilisation recommendations for production grasslands.
The rhizosphere selects for particular groups of acidobacteria and verrucomicrobia
Nunes da Rocha, U. ; Plugge, C.M. ; George, I. ; Elsas, J.D. van; Overbeek, L.S. van - \ 2013
PLoS ONE 8 (2013)12. - ISSN 1932-6203
16s ribosomal-rna - bacterial community structure - hitherto-uncultured bacteria - allium-porrum rhizosphere - soil microbial community - phylum acidobacteria - gen. nov. - subdivision 1 - forest soils - diversity
There is a lack in our current understanding on the putative interactions of species of the phyla of Acidobacteria and Verrucomicrobia with plants. Moreover, progress in this area is seriously hampered by the recalcitrance of members of these phyla to grow as pure cultures. The purpose of this study was to investigate whether particular members of Acidobacteria and Verrucomicrobia are avid colonizers of the rhizosphere. Based on previous work, rhizosphere competence was demonstrated for the Verrucomicrobia subdivision 1 groups of Luteolibacter and Candidatus genus Rhizospheria and it was hypothesized that the rhizosphere is a common habitat for Acidobacteria subdivision 8 (class Holophagae). We assessed the population densities of Bacteria, Verrucomicrobia subdivision 1 groups Luteolibacter and Candidatus genus Rhizospheria and Acidobacteria subdivisions 1, 3, 4, 6 and Holophagae in bulk soil and in the rhizospheres of grass, potato and leek in the same field at different points in time using real-time quantitative PCR. Primers of all seven verrucomicrobial, acidobacterial and holophagal PCR systems were based on 16S rRNA gene sequences of cultivable representatives of the different groups. Luteolibacter, Candidatus genus Rhizospheria, subdivision 6 acidobacteria and Holophaga showed preferences for one or more rhizospheres. In particular, the Holophaga 16S rRNA gene number were more abundant in the leek rhizosphere than in bulk soil and the rhizospheres of grass and potato. Attraction to, and colonization of, leek roots by Holophagae strain CHC25 was further shown in an experimental microcosm set-up. In the light of this remarkable capacity, we propose to coin strain CHC25 Candidatus Porrumbacterium oxyphilus (class Holophagae, Phylum Acidobacteria), the first cultured representative with rhizosphere competence
Improving national-scale carbon stock inventories using knowledge on land use history
Schulp, C.J.E. ; Verburg, P.H. ; Kuikman, P.J. ; Nabuurs, G.J. ; Olivier, J.G.J. ; Vries, W. de; Veldkamp, T. - \ 2013
Environmental Management 51 (2013)3. - ISSN 0364-152X - p. 709 - 723.
soil organic-carbon - landscape units - regional-scale - forest soils - belgium - dynamics - database - france - europe
National-scale inventories of soil organic carbon (SOC) and forest floor carbon (FFC) stocks have a high uncertainty. Inventories are often based on the interpolation of sampled information, often using a number of covariables to help such interpolation. The rationale for the choice of these covariables is not always documented, despite the fact that many local-scale studies have identified the factors explaining spatial variability of SOC and FFC stocks. These studies indicate, among others the importance of long-term land use history. Despite this, information on the effects of land use history has never been used to explain variability of carbon stocks in national-scale inventories. We designed an alternative method to improve national-scale inventories of SOC and FCC for the Dutch sand area that takes stock of the findings of detailed case studies. Determinants for SOC and FFC stocks derived from landscape-scale case studies were used to map national-scale spatial variability and to calculate national totals. The resulting national-scale spatial distribution was compared with the SOC stock map from the current Dutch greenhouse gas inventory. Using land use history to explain SOC variability decreased the error of the SOC stock estimate in 60 % of the area. The error in FFC stocks decreased in half of the forest area after including soil fertility, tree species, and forest age as explanatory factors. Estimates with reduced uncertainty will make land use and land management a more attractive and acceptable mitigation option to reduce emissions of greenhouse gases for the LULUCF sector.
Variation in soil carbon stocks and their determinants across a precipitation gradient in West Africa
Saiz, G. ; Bird, M.I. ; Domingues, T.F. ; Schrodt, F. ; Schwartz, M. ; Veenendaal, E.M. - \ 2012
Global Change Biology 18 (2012)5. - ISSN 1354-1013 - p. 1670 - 1683.
land-use change - organic-matter - biotic controls - cycle feedback - savanna soils - forest soils - sequestration - texture - senegal - stabilization
We examine the influence of climate, soil properties and vegetation characteristics on soil organic carbon (SOC) along a transect of West African ecosystems sampled across a precipitation gradient on contrasting soil types stretching from Ghana (15°N) to Mali (7°N). Our findings derive from a total of 1108 soil cores sampled over 14 permanent plots. The observed pattern in SOC stocks reflects the very different climatic conditions and contrasting soil properties existing along the latitudinal transect. The combined effects of these factors strongly influence vegetation structure. SOC stocks in the first 2 m of soil ranged from 20 Mg C ha-1 for a Sahelian savanna in Mali to over 120 Mg C ha-1 for a transitional forest in Ghana. The degree of interdependence between soil bulk density (SBD) and soil properties is highlighted by the strong negative relationships observed between SBD and SOC (r2 > 0.84). A simple predictive function capable of encompassing the effect of climate, soil properties and vegetation type on SOC stocks showed that available water and sand content taken together could explain 0.84 and 0.86 of the total variability in SOC stocks observed to 0.3 and 1.0 m depth respectively. Used in combination with a suitable climatic parameter, sand content is a good predictor of SOC stored in highly weathered dry tropical ecosystems with arguably less confounding effects than provided by clay content. There was an increased contribution of resistant SOC to the total SOC pool for lower rainfall soils, this likely being the result of more frequent fire events in the grassier savannas of the more arid regions. This work provides new insights into the mechanisms determining the distribution of carbon storage in tropical soils and should contribute significantly to the development of robust predictive models of biogeochemical cycling and vegetation dynamics in tropical regions.
Estimating nitrogen fluxes at the European scale by upscaling INTEGRATOR model outputs from selected sites
Reinds, G.J. ; Heuvelink, G.B.M. ; Hoogland, T. ; Kros, J. ; Vries, W. de - \ 2012
Biogeosciences 9 (2012)11. - ISSN 1726-4170 - p. 4527 - 4536.
no emissions - forest soils - n2o
A comparison was made between upscaled model results of nitrogen (N) fluxes to air and water from 450 sites within the EU27 and results derived for the entire EU27 area using the model INTEGRATOR. The 450 sites were selected using stratified random sampling, dividing the EU27 into 150 strata and selecting three sites at random within each stratum. The strata were based on important environmental factors influencing N fluxes. Hierarchical divisive cluster analysis was used to reduce the numerous combinations of environmental factors to the required total of 150, such that the heterogeneity of environmental factors within strata was as small as possible. Modelled NH3, N2O and NOx emissions and N leaching/runoff obtained were scaled up from the 450 sites to the entire EU27 and were within 10% of results obtained by running the model for the whole of the EU27. This implies that a reliable estimate of N fluxes for EU27can be made by upscaling results of the 450 selected sites suggesting that dramatic reductions in computation time can be achieved without substantial deterioration of results.
Scientific arguments for net carbon increase in soil organic matter in Dutch forests
Mol, J.P. ; Wyngaert, I.J.J. van den; Vries, W. de - \ 2012
Wageningen : Alterra (Alterra-report 2324) - 32
organisch bodemmateriaal - bosgronden - bossen - koolstofvastlegging - nederland - soil organic matter - forest soils - forests - carbon sequestration - netherlands
If reporting of emissions associated with Forest Management becomes obligatory in the next commitment period, the Netherlands will try to apply the 'not-a-source' principle to carbon emissions from litter and soil in land under Forest Management. To give a scientific basis for the principle of carbon stock change being 'not-a-source', a review is first made of the methods and arguments of other countries and the acceptance or disapproval by UNFCCC experts. Second, we investigated whether available Dutch datasets and literature information confirm the claim that Dutch forest soils are not a carbon source. This review indeed showed convincing arguments for soil being a carbon sink in the Netherlands under forest management, based on a combination of (i) measurements in Loobos, (ii) literature on soil carbon increases based on repeated measurement in comparable areas, (iii) N retention assessments, assuming that the soil C/N ratio stays constant, (iv) European scale modelling approaches on soil carbon changes including the Netherlands and (v) argumentation from expected changes in climate and N deposition in the Netherlands, combined with the results from meta-analysis and modelling.
Specific features of the ecological functioning of urban soils in Moscow and Moscow oblast
Vasenev, V.I. ; Ananyeva, N.D. ; Makarov, O.A. - \ 2012
Eurasian Soil Science 45 (2012)2. - ISSN 1064-2293 - p. 194 - 205.
microbial biomass carbon - land-use change - organic-carbon - metabolic quotient - forest soils - arable soils - ecosystems - ratios - qco2
Urban soils (constructozems) were studied in Moscow and several cities (Dubna, Pushchino, and Serebryanye Prudy) of Moscow oblast. The soil sampling from the upper 10-cm-thick layer was performed in the industrial, residential, and recreational functional zones of these cities. The biological (the carbon of the microbial biomass carbon, Cmic and the microbial (basal) respiration, BR) and chemical (pHwater and the contents of Corg, heavy metals, and NPK) indices were determined in the samples. The ratios of BR to Cmic (the microbial respiration quotient, qCO2) and of Cmic to Corg were calculated. The Cmic varied from 120 to 738 µg C/g soil; the BR, from 0.39 to 1.94 µg CO2-C/g soil per hour; the Corg, from 2.52 to 5.67%; the qCO2, from 1.24 to 5.28 µg CO2-C/mg Cmic/g soil per h; and the Cmic/Corg, from 0.40 to 1.55%. Reliable positive correlations were found between the Cmic and BR, the Cmic and Cmic/Corg, and the Cmic and Corg values (r = 0.75, 0.95, and 0.61, respectively), as well as between the BR and Cmic/Corg values (r = 0.68). The correlation between the Cmic/Corg and qCO2 values was negative (r = -0.70). The values of Cmic, BR, Corg, and Cmic/Corg were found to correlate with the ammonium nitrogen content. No correlative relationships were revealed between the determined indices and the climatic characteristics. The principal component analysis described 86% of the variances for all the experimental data and clearly subdivided the locations of the studied soil objects. The ANOVA showed that the variances of Cmic, Corg, and BR are controlled by the site location factor by 66, 63, and 35%, respectively. The specificity of the functioning of the anthropogenic soils as compared with their natural analogues was clearly demonstrated. As shown in this study, measurable biological indices might be applied to characterize the ecological, environmental-regulating, and productive functions of soils, including urban soils
Natural and fire-induced soil water repellency in a Portugese Shrubland
Stoof, C.R. ; Moore, D. ; Ritsema, C.J. ; Dekker, L.W. - \ 2011
Soil Science Society of America Journal 75 (2011)6. - ISSN 0361-5995 - p. 2283 - 2295.
coarse-textured soils - forest soils - pine forests - hydrological behavior - eucalyptus-globulus - spatial variability - prescribed fire - sandy soil - hydrophobicity - moisture
Post-fire land degradation is often attributed to fire-induced soil water repellency, despite the fact that soil water repellency is a natural phenomenon in many soils and is therefore not necessarily caused by fire. To improve our understanding of the role of soil water repellency in causing fire-induced land degradation, a long-term monitoring study was performed in which the temporal variation of topsoil water repellency (0–2.5-cm depth) was captured in a Portuguese shrubland before and after fire between November 2007 and March 2010. In addition, similarities and dissimilarities between changes following burning and clipping were assessed in a plot experiment. Soil water repellency appeared to be the rule rather than the exception, both before and after fire, and was strongly related to soil moisture and organic matter content. Surprisingly, despite the low soil temperatures during the fire (60°C) and the lack of direct soil moisture changes, fire significantly increased the persistence of soil water repellency (the water drop penetration time). Vegetation removal by burning and clipping played a key role in determining post-fire water repellency in litter and at the soil surface and considerably reduced the time needed to both develop and eliminate water repellency of the litter and surface soil. Where pre-fire (or “natural”) soil water repellency is abundant, an increase in erosion after fire cannot be solely caused by soil water repellency. Nevertheless, fire-induced removal of the protective canopy cover may increase the hydrologic significance of soil water repellency in burned landscapes
Effects of soil oven-drying on concentrations and speciation of trace metals and dissolved organic matter in soil solution extracts of sandy soils
Koopmans, G.F. ; Groenenberg, J.E. - \ 2011
Geoderma 161 (2011)3-4. - ISSN 0016-7061 - p. 147 - 158.
m calcium-chloride - phosphorus solubility - ion activity - agricultural soils - heavy-metals - forest soils - water - binding - carbon - copper
Weak salt extracts can be used to assess the availability of trace metals for leaching and uptake by soil organisms and plants in soil. Before extraction, the International Organization for Standardization recommends to dry soils in an oven at a temperature of 40 °C. Effects of soil oven-drying on different fractions of dissolved organic matter (DOM) and the effect thereof on total concentrations and speciation of trace metals in weak salt extracts have, however, not been quantified yet. In this study, free metal concentrations and DOM speciation were determined in 2 mM Ca(NO3)2 extracts obtained from twelve field-contaminated soils in their field-moist state and after drying at 40 °C. Free metal concentrations were measured with the Donnan Membrane Technique. DOM was fractioned into humic acid (HA), fulvic acid (FA), and hydrophilic (Hy) compounds. Soil oven-drying led to significant increases in the concentrations of total DOM and total dissolved Cu and Ni. For the measurement of total dissolved Cu and Ni concentrations, it is, therefore, better to use field-moist soils. The release of Hy compounds was mainly responsible for the increase in DOM, which accounted for 64 to 77% of the increase in total dissolved organic carbon. Soil oven-drying left the free Cd2+, Cr3+, Cu2+, Ni2+, and Zn2+ concentrations unchanged. Both field-moist and oven-dried soils can, therefore, be used for the measurement of free metal concentrations. Free Cd2+, Cu2+, Ni2+, and Zn2+ concentrations were predicted very well for both field-moist and oven-dried soils using ORCHESTRA, which includes the NICA-Donnan model. However, poor predictions were obtained for Cr3+, for which better NICA parameters need to be derived. --------------------------------------------------------------------------------
Quantifying impacts of nitrogen use in European agriculture on global warming potential.
Vries, W. de; Kros, J. ; Reinds, G.J. ; Butterbach-Bahl, K. - \ 2011
Current Opinion in Environmental Sustainability 3 (2011)5. - ISSN 1877-3435 - p. 291 - 302.
greenhouse-gas inventory - c-n-p - forest soils - carbon sequestration - oxide emissions - climate-change - n2o budget - deposition - methane - management
This paper summarizes current knowledge on the impacts of changes of nitrogen (Nr) use in agriculture on the global warming potential (GWP) by its impact on carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) emissions from agricultural and terrestrial nonagricultural systems and from aquatic and marine ecosystems. Ranges in ‘N induced exchange factors’, giving responses of CO2–C, N2O–N and CH4–C exchange per kg N input, are presented for all ecosystems. Using these factors, a quantification is made of CO2, N2O and CH4 exchange (emissions or uptake) induced by the use of Nr in agriculture at European scale for the year 2000. This includes: (i) direct impacts in the agricultural systems due to Nr inputs by fertilizer and manure and NH3 deposition and (ii) indirect impacts due to Nr leaching and NH3 deposition caused by agriculture on terrestrial, aquatic and marine ecosystems. Results show that the increase in GWP caused by elevated N2O emission due to Nr use in agriculture is completely counteracted by elevated carbon sequestration in nonagricultural systems. Nr effects on biodiversity, eutrophication and human health, however, need to be considered when considering the overall impacts of Nr use in agriculture.
Predicting soil N mineralization: Relevance of organic matter fractions and soil properties.
Ros, G.H. ; Hanegraaf, M.C. ; Hoffland, E. ; Riemsdijk, W.H. van - \ 2011
Soil Biology and Biochemistry 43 (2011)8. - ISSN 0038-0717 - p. 1714 - 1722.
nitrogen mineralization - microbial biomass - chemical methods - grassland soils - forest soils - indexes - availability - carbon - respiration - temperature
Distinct extractable organic matter (EOM) fractions have been used to assess the capacity of soils to supply nitrogen (N). However, substantial uncertainty exists on their role in the N cycle and their functional dependency on soil properties. We therefore examined the variation in mineralizable N and its relationship with EOM fractions, soil physical and chemical properties across 98 agricultural soils with contrasting inherent properties and management histories. Mineralizable N was determined by aerobic incubation at 20 °C and optimum moisture content for 20 weeks. We used multivariate statistical modelling to account for multi-collinearity, an issue generally overlooked in studies evaluating the predictive value of EOM fractions. Mineralization of N was primarily related to the size of OM pools and fractions present; they explained 78% of the variation in mineralizable N whereas other soil variables could explain maximally 8%. Both total and extractable OM expressed the same soil characteristic from a mineralization perspective; they were positively related to mineralizable N and explained a similar percentage of the variation in mineralizable N. Inclusion of mineralizable N in fertilizer recommendation systems should be based on at least one OM variable. The most appropriate EOM fraction can only be identified when the underlying mechanisms are known; regression techniques are not suitable for this purpose. Combination of single EOM fractions is not likely to improve the prediction of mineralizable N due to high multi-collinearity. Inclusion of texture-related soil variables or variables reflecting soil organic matter quality may be neglected due to their limited power to improve the prediction of mineralizable N.
Comparison of land nitrogen budgets for European agriculture by various modeling approaches
Vries, W. de; Leip, A. ; Reinds, G.J. ; Lesschen, J.P. ; Bouwman, A.F. - \ 2011
Environmental Pollution 159 (2011)11. - ISSN 0269-7491 - p. 3254 - 3268.
no emissions - forest soils - n2o - inventory - ecosystems - balances - losses - fields - carbon - water
A comparison of nitrogen (N) budgets for the year 2000 of agro-ecosystems is made for the EU 27 countries by four models with different complexity and data requirements, i.e. INTEGRATOR, IDEAg, MITERRA and IMAGE. The models estimate a comparable total N input in European agriculture, i.e. 23.3–25.7 Mton N yr-1, but N uptake varies more, i.e. from 11.3 to 15.4 Mton N yr-1 leading to total N surpluses varying from 10.4 to 13.2 Mton N yr-1. The estimated overall variation at EU 27 is small for the emissions of ammonia (2.8–3.1 Mton N yr-1) and nitrous oxide (0.33–0.43 Mton N yr-1), but large for the sum of N leaching and runoff (2.7–6.3 Mton N yr-1). Unlike the overall EU estimates, the difference in N output fluxes between models is large at regional scale. This is mainly determined by N inputs, differences being highest in areas with high livestock density.
Effecten van verzuring op bodemleven en stikstofstromen in bossen : verkenning van mogelijkheden voor herstelmaatregelen
Kemmers, R.H. - \ 2011
Wageningen : Alterra (Alterra-rapport 2204) - 42
verzuring - bodemchemie - bodembiodiversiteit - bosgronden - stikstofbalans - stikstofkringloop - ecologisch herstel - acidification - soil chemistry - soil biodiversity - forest soils - nitrogen balance - nitrogen cycle - ecological restoration
Dit rapport geeft een samenvatting van de resultaten van de analyses van het bodemleven, de stikstofstromen en bodemcondities over een brede range van bosgronden. In dit rapport staat de vraag centraal of door verzuring de relatie tussen ondergrondse en bovengrondse biodiversiteit via de N-kringloop is beinvloed. De conclusie is dat door verzuring de activiteit van bacterien (protozoa) en regenwormen is afgenomen en die van schimmels, nematoden en potwormen is toegenomen. Hierdoor is een verschuiving opgetreden in de stikstofbalans van N-immobilisatie naar netto N-mineralisatie. Hiervan profiteren opportunistische soorten in de ondergroei door het extra N-aanbod om te zetten in biomassa waardoor kritischer soorten worden benadeeld. Herstelmaatregelen moeten gericht zijn op herstel van de N-balans tussen bovengronds en ondergronds leven in de richting van een grotere N-retentie door het bodemleven. Hierin kan via het beheer worden gestuurd.
SOMPROF: A vertically explicit soil organic matter model
Braakhekke, M.C. ; Beer, M. ; Hoosbeek, M.R. ; Kruijt, B. ; Kabat, P. - \ 2011
Ecological Modelling 222 (2011)10. - ISSN 0304-3800 - p. 1712 - 1730.
temperature sensitivity - carbon dynamics - atmospheric co2 - climate-change - forest soils - elevated co2 - turnover - respiration - transport - decomposition
Most current soil organic matter (SOM) models represent the soil as a bulk without specification of the vertical distribution of SOM in the soil profile. However, the vertical SOM profile may be of great importance for soil carbon cycling, both on short (hours to years) time scale, due to interactions with the soil temperature and moisture profile, as well as on long (years to centuries) time scale because of depth-specific stabilization mechanisms of organic matter. It is likely that a representation of the SOM profile and surface organic layers in SOM models can improve predictions of the response of land surface fluxes to climate and environmental variability. Although models capable of simulating the vertical SOM profile exist, these were generally not developed for large scale predictive simulations and do not adequately represent surface organic horizons. We present SOMPROF, a vertically explicit SOM model, designed for implementation into large scale ecosystem and land surface models. The model dynamically simulates the vertical SOM profile and organic layer stocks based on mechanistic representations of bioturbation, liquid phase transport of organic matter, and vertical distribution of root litter input. We tested the model based on data from an old growth deciduous forest (Hainich) in Germany, and performed a sensitivity analysis of the transport parameters, and the effects of the vertical SOM distribution on temporal variation of heterotrophic respiration. Model results compare well with measured organic carbon profiles and stocks. SOMPROF is able to simulate a wide range of SOM profiles, using parameter values that are realistic compared to those found in previous studies. Results of the sensitivity analysis show that the vertical SOM distribution strongly affects temporal variation of heterotrophic respiration due to interactions with the soil temperature and moisture profile.
Simulation of daily Nitrous Oxide emissions from managed peat soils
Stolk, P.C. ; Hendriks, R.F.A. ; Jacobs, C.M.J. ; Duyzer, J. ; Moors, E.J. ; Groenigen, J.W. van; Kroon, P.S. ; Schrier-Uijl, A.P. ; Veenendaal, E.M. ; Kabat, P. - \ 2011
Vadose Zone Journal 10 (2011)1. - ISSN 1539-1663 - p. 156 - 168.
covariance flux measurements - n2o emissions - water-flow - grazed grasslands - model development - rainfall events - co2 exchange - forest soils - new-zealand - denitrification
Simulation of emissions of the greenhouse gas N2O from agricultural land is still a challenge. This is mainly due to its high temporal variability, with low background emissions and a few transient peaks. In this study, a first attempt was made to simulate observations of N2O fluxes with a daily time step from managed peat soils. We used a new N2O module added to the extensively tested hydrological–biogeochemical model combination SWAP-ANIMO, hypothesizing that accurate simulation of the controlling factors would imply accurate simulation of the dynamics of the N2O emissions as well. We used daily N2O emission data from three sites in the Netherlands, with complementary data on soil moisture, mineral N content, and soil N2O concentration. Simulation of soil moisture, mineral N, and N2O concentration was reasonable to good. Still, simulation of the daily N2O emissions was poor, with model efficiencies
Assessing denitrification and N leaching in a field with organic amendments
Radersma, S. ; Smit, A.L. - \ 2011
NJAS Wageningen Journal of Life Sciences 58 (2011)1-2. - ISSN 1573-5214 - p. 21 - 29.
nitrate vulnerable zone - paper-mill sludge - crop yields - nitrogen mineralization - plant residues - barley straw - forest soils - decomposition - management - release
Denitrification and leaching of nitrogen (N) from agriculture are a loss of nutrients to farmers and sources of pollution to water and air, and should therefore be minimized. In a field experiment on loamy soil, denitrification and N leaching were measured after late summer incorporation of fodder radish residues with or without paper pulp as N-immobilizing organic material. A set of relatively simple methods were used to measure and calculate denitrification and N leaching during the first two weeks after application and during the rest of the winter period. The methods were acetylene inhibition of nitrification, anion-exchange resin, the mineralization model MINIP, and inorganic-N balance calculations. Paper pulp increased N immobilization after the first day of application throughout the winter. This led to a 63–70% reduction in N losses compared with the sole fodder radish field and with the control. Denitrification was highest in the sole fodder radish treatment, at 65% of its total N losses. N leaching during the winter period was highest in the control, at 70% of its total N losses. This N was mainly liberated by mineralization of soil organic matter after ploughing in late summer. The application of paper pulp plus fodder radish did not affect sugar beet yields in the next year. The methodology for determining leaching and denitrification enabled the assessment of differences among treatments. It showed clearly that paper pulp strongly reduced N losses on this type of soil. The anion resin method that was used to measure leaching during the winter period showed clear and consistent differences between treatments, but may need additional calibration before fully relying on the absolute amounts of N leached
Dynamics of dissolved and extractable organic nitrogen upon soil amendment with crop residues
Ros, G.H. ; Hoffland, E. - \ 2010
Soil Biology and Biochemistry 42 (2010)12. - ISSN 0038-0717 - p. 2094 - 2101.
microbial biomass - mineralizable nitrogen - agricultural soils - salt-solutions - forest soils - matter - carbon - n-15 - electroultrafiltration - fractions
Dissolved organic nitrogen (DON) is increasingly recognized as a pivotal pool in the soil nitrogen (N) cycle. Numerous devices and sampling procedures have been used to estimate its size, varying from in situ collection of soil solution to extraction of dried soil with salt solutions. Extractable organic N (EON) not only consists of DON but contains also compounds released from soil biomass and desorbed organic matter. There is no consensus whether DON or EON primarily regulates N mineralisation in soil, and their contribution to N mineralisation has not been quantified simultaneously. We evaluated three sampling procedures on their ability to determine the dynamic of dissolved organic N pools. The three procedures were the determination of DON in 1) soil solution collected by centrifugation, and the determination of EON in 2) a 0.01 M CaCl2 extract of field moist or 3) dried soil. We added unlabeled leek and 15N-labeled ryegrass residues to a loamy sandy soil to create a temporarily increase in DON and EON, to stimulate microbial activity, and to test whether the source and dynamics of the three pools differ. We also tested whether the flow of N through DON or EON was associated with the production of inorganic N using 15N isotope tracing. Sampling procedures significantly affected the amount, but not the dynamics and origin of the three organic N pools. DON and EON (determined on field-moist and dried soils) showed all a significant increase upon crop amendment and returned to their background concentrations within 10 to 30 days. The fraction of DON and EON originating from the crop residue slightly decreased over 138 days and was not different for DON and EON. Field moist extraction of a loamy sandy soil with 0.01 M CaCl2 gave a reliable estimate of the concentration of in situ dissolved organic N. In contrast, extraction of dried soil significantly increased EON compared to DON. The agreement in dynamics, 15N enrichment and C-to-N ratio’s indicate that dissolved and extracted organic N have a similar role in N mineralisation. Our results also suggest that they make a minor contribution to N mineralisation; changes in the turnover rate of EON were not associated with changes in the net N mineralisation rate
Oliebollen in de zomer
Roobeek, K. - \ 2010
Nature Today 2010 (2010)14-07.
bosecologie - rhizina undulata - bedreigde soorten - bosgronden - bodemflora - flora - ecologisch herstel - forest ecology - rhizina undulata - endangered species - forest soils - soil flora - flora - ecological restoration
De oliebolzwam is een typische brandplekpaddenstoel die nu ondanks de grote droogte en hitte bij Schoorl te vinden is. Vroeger algemeen voorkomend als de koffievuurtjeszwam, is het nu in Nederland een bedreigde soort.
Air pollution impacts on European forest soils: steady-state and dynamic modelling
Reinds, G.J. - \ 2009
Wageningen University. Promotor(en): Rik Leemans, co-promotor(en): Wim de Vries; M. Posch. - [S.l.] : S.n. - ISBN 9789085855200 - 223
bodemchemie - bosgronden - ecosystemen - stikstof - europa - luchtverontreiniging - verzuring - zure regen - klimaatverandering - modelleren - soil chemistry - forest soils - ecosystems - nitrogen - europe - air pollution - acidification - acid rain - climatic change - modeling
Zure regen heeft in Europa geleid tot verzuring van bodems en oppervlaktewater. In bosbodems nam de buffercapaciteit af en de bossen werden gevoeliger voor stress als gevolg van, bijvoorbeeld, verstoorde nutriëntenbalansen veroorzaakt door een teveel aan stikstof in de bodem. Deze overmaat aan stikstof veroorzaakte ook veranderingen in natuurlijke vegetaties (meer stikstofminnende soorten). In oppervlaktewater zijn duidelijke schadelijke effecten waargenomen als gevolg van verzuring: in de jaren 70 en 80 trad, vooral in Scandinavië, grote sterfte op onder gevoelige vissoorten. Overmaat aan stiktof leidde lokaal tot eutrofiëring van oppervlaktewater. Kritische depositieniveaus worden meestal berekend met een computermodel dat de bodemverzuring simuleert. Er zijn vele bodemverzuringsmodellen ontwikkeld, maar de meeste daarvan zijn alleen toegepast op puntlocaties en/of regio’s en bovendien zijn de modellen zelden gecalibreerd op grote, regionale datasets. Het doel van dit proefschrift was om (a) na te gaan of beschikbare gegevens uit Europese bosmonitoringsprogramma’s kunnen worden gebruikt om een eenvoudig bodemverzuringsmodel te calibreren (b) op basis van de calibratie na te gaan hoe onzeker de modeluitkomsten zijn en of deze onzekerheid door modelcalibratie afneemt (c) het model toe te passen op Europa en Noord Azië en (d) vast te stellen of de afname van zure depositie leidt to herstel van bodemverzuring in Europa en na te gaan of klimaatverandering daar een invloed op heeft
Effect of temporal resolution on N2O emission inventories in Dutch fen meadows
Nol, L. ; Heuvelink, G.B.M. ; Vries, W. de; Kros, J. ; Moors, E.J. ; Verburg, P.H. - \ 2009
Global Biogeochemical Cycles 23 (2009). - ISSN 0886-6236 - 15
distikstofmonoxide - broeikasgassen - emissie - schattingen - laagveengronden - veenweiden - regen - nederland - nitrous oxide - greenhouse gases - emission - estimates - fen soils - peat grasslands - rain - netherlands - nitrous-oxide emissions - fertilizer application rate - greenhouse-gas emissions - pasture simulation-model - pnet-n-dndc - managed grasslands - field validation - forest soils - nitric-oxide - peat soil
Most countries use a 1-year-resolution emission factor approach (Tier 1 or 2) to estimate terrestrial N2O emissions as part of their national greenhouse gas inventory. Little attention has so far been paid to the effect of the temporal resolution of the approach (e.g., day, season, and year) on N2O emission estimates. The effect of lumping temporal variation can be very large because of daily or seasonal variations of processes causing N2O emissions. Therefore, we compared annual N2O emissions from a model with daily time steps (DNDC) with those of a model with annual time steps (INITIATOR). Emissions were simulated for two intensively managed grassland plots in the Dutch fen meadow landscape. Annual N2O emissions from the investigated grasslands were sensitive to rainfall distribution within the year, especially to summer rainfall. We recommend that Tier 2 N2O emission estimates for intensively managed grasslands on peat soils in the temperate climate zone are adjusted for relative summer rainfall
Habitat type-based bioaccumulation and risk assessment of metal and As contamination in earthworms, beetles and woodlice
Vermeulen, F. ; Brink, N.W. van den; Havé, H. D'; Mubiana, V.K. ; Blust, R. ; Bervoets, L. ; Coen, W. De - \ 2009
Environmental Pollution 157 (2009)11. - ISSN 0269-7491 - p. 3098 - 3105.
hedgehog erinaceus-europaeus - spatial-distribution - forest soils - heavy-metals - trace-metals - accumulation - pollution - spectrometry - floodplain - microwave
The present study investigated the contribution of environmental factors to the accumulation of As, Cd, Cu, Pb and Zn in earthworms, beetles and woodlice, and framed within an exposure assessment of the European hedgehog. Soil and invertebrate samples were collected in three distinct habitat types. Results showed habitat-specific differences in soil and invertebrate metal concentrations and bioaccumulation factors when normalized to soil metal concentration. Further multiple regression analysis showed residual variability (habitat differences) in bioaccumulation that could not be fully explained by differences in soil metal contamination, pH or organic carbon (OC). Therefore, the study demonstrated that in bioaccumulation studies involving terrestrial invertebrates or in risk assessment of metals, it is not sufficient to differentiate habitat types on general soil characteristics such as pH and/or OC alone. Furthermore, simple generic soil risk assessments for Cd and Cu showed that risk characterization was more accurate when performed in a habitat-specific way. Our study provided essential insights into habitat-specific accumulation patterns with respect to factors influencing metal bioaccumulation, BAFs, and site-specific risk assessment
Extractable and dissolved soil organic nitrogen - A quantitative assessment
Ros, G.H. ; Hoffland, E. ; Kessel, C. van; Temminghoff, E.J.M. - \ 2009
Soil Biology and Biochemistry 41 (2009)6. - ISSN 0038-0717 - p. 1029 - 1039.
common arable topsoils - 0.01 m cacl2 - microbial biomass - n-mineralization - norway spruce - agricultural soils - forest soils - sandy soils - seasonal-changes - pastoral soils
Extractable Organic N (EON) or Dissolved Organic Nitrogen (DON) pools are often analyzed to predict N mineralisation, N leaching, and to evaluate agricultural (nutrient) management practices. Size and characteristics of both pools, however, are strongly influenced by methodology. Quantifying the influence of methodology can increase the accuracy of soil tests to predict N mineralisation, improve model simulations, and can help to quantify the contribution of the EON and DON pools to soil N cycling. We estimated the relative impact of methodological, management, and environmental factors on EON and DON, using a meta-analysis approach based on 127 studies. Our results indicate that the EON and DON pools are neither similar in size nor controlled by the same factors. The influence of factors controlling EON generally decreased in the order of methodology (¿10¿2400%), followed by environment (¿11¿270%) and management (¿16¿77%). DON concentrations were primarily controlled by management factors: different land use and fertilisation caused a variation of 37¿118%. Seasonal variations in DON concentrations were generally smaller than variations in EON, suggesting that high mineralisation and sorption rates buffer DON. The large range in EON as affected by different methodology emphasizes the importance of using appropriate and standardized methods for the determination of EON. The determination of DON can be useful to estimate leaching losses. EON, however, can be used to assess the impact of soil management practices on the turnover rate of labile soil organic matter pools
Soil development on Late Quaternary river terraces in a high montane valley in Bhutan, Eastern Himalayas
Tshering Dorji, ; Caspari, T. ; Bäumler, R. ; Veldkamp, A. ; Jongmans, A.G. ; Kado Tshering, ; Tsheten Dorji, ; Baillie, I. - \ 2009
Catena 78 (2009)1. - ISSN 0341-8162 - p. 48 - 59.
forest soils - climate - history - chronosequences - evolution - cations - fungi
We examined the geochemistry and micromorphology of the soils on a suite of morphologically well-defined and visually distinct fluvial terraces, up to 40 m elevation above the current riverbed, at Thangbi in the upper Bumthang Valley, Bhutan. The alluvia forming each of the terraces are lithologically and structurally similar, with shallow or moderately deep, clast-free sandy loam overbank deposits capping deep clast-supported beds of rounded boulders and interstitial sand. The topsoils on the 40 m terrace have more silt than those on the lower terraces. The soils are interpreted mainly as a monoclinal post-incisive chronosequence. Features that indicate progressive pedogenesis with increasing elevation include subsoil rubefaction, crystallinity of free Fe sesquioxides, and weathering of susceptible primary minerals, such as biotite and hornblende. However other soil attributes show no systematic trends and the overall impression is of limited pedogenesis, even in the soils on the higher terraces. We examine possibilities that the immaturity of the soils is due to pedogenic rejuvenation by post-incision additions to the soil parent materials.
The effect of naturally acidified irrigation water on agricultural volcanic soils. The case of Asembagus, Java, Indonesia
Los, A.M.D. ; Vriend, S.P. ; Bergen, M.J. ; Gaans, R.F.M. - \ 2008
Journal of Geochemical Exploration 96 (2008)1. - ISSN 0375-6742 - p. 53 - 68.
mine tailings - forest soils - acidification - netherlands - deposition - aluminum - elements - sulfate - river - iron
Acid water from the Banyuputih river (pH similar to 3.5) is used for the irrigation of agricultural land in the Asembagus coastal area (East Java, Indonesia), with harmful consequences for rice yields. The river water has an unusual composition which is caused by seepage from the acidic Kawah Ijen crater lake into the river. This unique irrigation setting allows the study of soil acidification in situ. This paper assesses the effects of volcanogenically contaminated irrigation water on the chemical properties of the agricultural soils. The changes in soil properties were evaluated by comparing samples taken from the topsoil and sub-soil (1-3 m depth) from areas irrigated with acid water and areas irrigated with neutral water. The field survey thus resulted in four soil categories. Bulk soil composition, organic matter content, moisture content and particle size distribution were determined. Reactive phases were quantified with the selective extractions 1 M KCl, 0.1 M Na-pyrophosphate and 0.2 M acid ammonium oxalate (AAO). By comparing the four soil categories it is shown that the use of the naturally polluted irrigation water has had a large influence on the chemical composition of the topsoil. The composition of the soil solution has changed over the entire investigated soil profile. Furthermore the acid irrigation water has strongly modified the composition of the reactive phases, extracted as KCl, pyrophosphate, and AAO extractable elements, and also the bulk soil composition has been significantly modified. Overall this has resulted in the net dissolution of some elements and the net precipitation of others. The changes in the reactive phases and bulk soil composition are only apparent in the topsoil (0-20 cm) but not in the deeper soil.
Zieke bodem zorgt voor lelijk bos
Kemmers, R.H. - \ 2008
Kennis Online 2008 (2008)nov. - p. 3 - 3.
natuurbescherming - bodem - biologische bodemactiviteit - achteruitgang, bossen - bosecologie - bosgronden - natuur - nature conservation - soil - biological activity in soil - forest decline - forest ecology - forest soils - nature
Op de bosgrond onder de bomen zouden allerhande mossen, bloemen en kruiden moeten kunnen groeien. In Nederland lijdt de kwaliteit van de ondergroei echter al enkele decennia onder verzuring, vermesting en verdroging. Natuurbeheerders doen hun best om de schade te herstellen, maar de genomen maatregelen hebben nog onvoldoende effect. De gewenste planten komen pas terug als de basis goed is: de bodem
Critical loads of metals and other trace elements to terrestrial environments.
Lofts, S. ; Chapman, P. ; Dwyer, R. ; McLaughlin, M. ; Schoeters, I. ; Sheppard, S. ; Adams, W. ; Alloway, B. ; Antunes, P. ; Campbell, P. ; Davies, B. ; Degryse, F. ; Vries, W. de; Groenenberg, J.E. - \ 2007
Environmental Science and Technology 41 (2007)18. - ISSN 0013-936X - p. 6326 - 6331.
forest soils - heavy-metals - cadmium - copper - balances - quality - risk
Effecten van het generieke milieubeleid op het terugdringen van de verzuring en het herstel van natuurwaarden in multifunctionele bossen op arme zandgronden
Kemmers, R.H. ; Dobben, H.F. van; Wamelink, G.W.W. - \ 2007
Wageningen : Alterra (Alterra-rapport 1531) - 83
zandgronden - bosgronden - bosschade - vegetatie - emissie - stikstof - verzuring - herstel - bodembiologie - meervoudig gebruik - bossen - nederland - milieubeleid - ecosystemen - natuurwaarde - sandy soils - forest soils - forest damage - vegetation - emission - nitrogen - acidification - rehabilitation - soil biology - multiple use - forests - netherlands - environmental policy - ecosystems - natural value
Via beschikbare gegevens is geëvalueerd of het generiek milieubeleid sinds 1990 heeft geleid tot terugdringen van de verzuring en vermesting en op herstel van natuurwaarden van Multifunctionele bossen. Als basis voor de evaluatie zijn bodem- en vegetatiegegevens van ca. 200 opstanden uit het meetnet ‘Vitaliteit en Verdroging’ geanalyseerd. Zowel het bodemchemisch als het vegetatiekundig onderzoek bevestigt dat er in multifunctionele bossen sprake is van een licht herstel van de zuurgraad en een daling van ammoniumgehalten. Er is nog steeds sprake van een voortgezette strooiselaccumulatie, waarschijnlijk als gevolg van een weinig actief bodemleven.
Selective depletion of organic matter in mottled podzol horizons
Buurman, P. ; Schellekens, J.F.P. ; Fritze, H. ; Nierop, K.G.J. - \ 2007
Soil Biology and Biochemistry 39 (2007)2. - ISSN 0038-0717 - p. 607 - 621.
chromatography mass-spectrometry - forest soils - chemical characterization - microbial communities - c-13 nmr - pyrolysis - decomposition - acids - biomass - fungi
Some well-drained podzols on quartz sands in the Netherlands and neighbouring Belgium and Germany show mottling in all horizons due to selective removal of organic matter. Phospholipid analysis and morphology of the mottles suggests that this removal is due to a combination of bacteria, fungi, and actinomycetes. Investigation by pyrolysis-GC/MS of organic matter in the depleted zones as compared to their surroundings indicates (1) selective decay of relatively palatable components, (2) residual accumulation of aliphatic biopolymers such as cutan and suberan that produce alkanes, alkenes and methylketones upon pyrolysis, and (3) accumulation of microbial polysaccharides and N-containing compounds. Although the selective organic matter decay in the depleted mottles is similar to the process that causes degradation of organic matter at the top of the B-horizon and its conversion to an E-horizon, the essential difference is that, while decay at the E¿B-horizon transition in podzols is governed by the presence or absence of aluminium and iron, the micro flora that is responsible for the decay mottles acts independently from metal concentrations.
Total soil C and N sequestration in a grassland following 10 years of free air CO2 enrichment
Kessel, C. van; Boots, B. ; Graaff, M.A. de; Harris, D. ; Blum, H. ; Six, J. - \ 2006
Global Change Biology 12 (2006)11. - ISSN 1354-1013 - p. 2187 - 2199.
elevated atmospheric co2 - trifolium-repens l - organic-matter - carbon-dioxide - lolium-perenne - n-15-labeled fertilizer - litter quality - nitrogen pools - forest soils - plant
Soil C sequestration may mitigate rising levels of atmospheric CO2. However, it has yet to be determined whether net soil C sequestration occurs in N-rich grasslands exposed to long-term elevated CO2. This study examined whether N-fertilized grasslands exposed to elevated CO2 sequestered additional C. For 10 years, Lolium perenne, Trifolium repens, and the mixture of L. perenne/T. repens grasslands were exposed to ambient and elevated CO2 concentrations (35 and 60 Pa pCO(2)). The applied CO2 was depleted in delta C-13 and the grasslands received low (140 kg ha(-1)) and high (560 kg ha(-1)) rates of N-15-labeled fertilizer. Annually collected soil samples from the top 10 cm of the grassland soils allowed us to follow the sequestration of new C in the surface soil layer. For the first time, we were able to collect dual-labeled soil samples to a depth of 75 cm after 10 years of elevated CO2 and determine the total amount of new soil C and N sequestered in the whole soil profile. Elevated CO2, N-fertilization rate, and species had no significant effect on total soil C. On average 9.4 Mg new C ha(-1) was sequestered, which corresponds to 26.5% of the total C. The mean residence time of the C present in the 0-10 cm soil depth was calculated at 4.6 +/- 1.5 and 3.1 +/- 1.1 years for L. perenne and T. repens soil, respectively. After 10 years, total soil N and C in the 0-75 cm soil depth was unaffected by CO2 concentration, N-fertilization rate and plant species. The total amount of N-15-fertilizer sequestered in the 0-75 cm soil depth was also unaffected by CO2 concentration, but significantly more N-15 was sequestered in the L. perenne compared with the T. repens swards: 620 vs. 452 kg ha(-1) at the high rate and 234 vs. 133 kg ha(-1) at the low rate of N fertilization. Intermediate values of N-15 recovery were found in the mixture. The fertilizer derived N amounted to 2.8% of total N for the low rate and increased to 8.6% for the high rate of N application. On average, 13.9% of the applied N-15-fertilizer was recovered in the 0-75 cm soil depth in soil organic matter in the L. perenne sward, whereas 8.8% was recovered under the T. repens swards, indicating that the N-2-fixing T. repens system was less effective in sequestering applied N than the non-N-2-fixing L. perenne system. Prolonged elevated CO2 did not lead to an increase in whole soil profile C and N in these fertilized pastures. The potential use of fertilized and regular cut pastures as a net soil C sink under long-term elevated CO2 appears to be limited and will likely not significantly contribute to the mitigation of anthropogenic C emissions.
Effect of land use on the composition of soil organic matter in density and aggregate fractions as revealed by solid-state 13C NMR spectroscopy
Helfrich, M. ; Ludwig, B. ; Buurman, P. ; Flessa, H. - \ 2006
Geoderma 136 (2006)1-2. - ISSN 0016-7061 - p. 331 - 341.
chemical-composition - humic substances - forest soils - carbon - cultivation - residues - dynamics - plant - cpmas
Changes in soil organic carbon (SOC) contents with soil cultivation have been investigated extensively, but information on the influence of land use changes on the chemistry of soil organic matter (SOM) and SOM fractions is scarce. To make a contribution in this context, we sampled silty soils under different land use (spruce forest (Ah horizon, 0-7 cm), continuous maize cropping (Ap horizon, 0¿30 cm), and grassland (Ah horizon, 0-10 cm)) as well as the organic layer (L, Of, and Oh) of the forest floor and collected plant materials from the three sites. Separation of SOM density fractions (free particulate organic matter, occluded particulate organic matter, and mineral-associated organic matter) and water-stable aggregate size fractions of the surface soils was performed in order to follow changes in the chemical composition of SOM in physical soil fractions using CPMAS 13C NMR spectroscopy and to determine land use effects on the chemistry of SOM fractions. The CPMAS 13C NMR spectra showed that maize litter had the highest content of O-alkyl-C and the lowest content of alkyl-C, aryl-C and carbonyl-C compared with the plant material from the spruce stand and the grassland. The forest litter had the largest content of aromatic and alkyl-C. Decomposition of spruce litter in the humus layer resulted in a decreasing O-alkyl-C content and an increasing alkyl-C content. The SOM of the acid forest soil consisted mainly of particulate organic matter (POM) with a high content of spruce litter-derived alkyl-C. The SOC stocks in the grassland and maize soil were dominated by mineral-associated SOM which contained relatively larger proportions of aryl and carbonyl-C. The decrease of the SOC concentration induced by cultivation resulted in a relative accumulation of aromatic C structures in the mineral-bound SOM. In all soils, the free POM had a smaller proportion of alkyl-C and a larger proportion of O-alkyl-C than the POM occluded in aggregates. The mean age of the SOM in the density fractions of the maize soil increased with increasing aromaticity in the order free POM
Fungal/bacterial ratios in grassland with contrasting nitrogen management
Vries, F.T. de; Hoffland, E. ; Eekeren, N.J.M. van; Brussaard, L. ; Bloem, J. - \ 2006
Soil Biology and Biochemistry 38 (2006)8. - ISSN 0038-0717 - p. 2092 - 2103.
soil microbial communities - clover trifolium-repens - arbuscular mycorrhizal fungi - bacterial biomass ratios - ryegrass lolium-perenne - white clover - organic-matter - upland grassland - forest soils - leucine incorporation
It is frequently hypothesised that high soil fungal/bacterial ratios are indicative for more sustainable agricultural systems. Increased F / B ratios have been reported in extensively managed grasslands. To determine the shifts in fungal/bacterial biomass ratio as influenced by grassland management and to find relations with nitrogen leaching potential, we sampled a two-year-old field experiment at an organic experimental farm in the eastern part of The Netherlands. The effect of crop (grass and grass-clover), N application rate (0, 40, 80, 120 kg N ha- 1) and manure type (no manure, farm yard manure and slurry) on the F / B ratio within three growing seasons was tested, as well as relations with soil and crop characteristics, nitrate leaching and partial N balance. Biomass of fungi and bacteria was calculated after direct counts using epifluorescence microscopy. Fungal and bacterial biomass and the F / B ratio were higher in grass than in grass-clover. The F / B ratio decreased with increasing N application rate and multiple regression analysis revealed a negative relationship with pH. Bacterial activity (measured as incorporation of [3H]thymidine and [14C]leucine into bacterial DNA and proteins) showed the exact opposite: an increase with N application rate and pH. Leaching increased with N application rate and was higher in grass-clover than in grass. Partial N balance was more positive at a higher N application rate and showed an inverse relationship with fungal biomass and F / B ratio. We conclude that the fungal/bacterial biomass ratio quickly responded to changes in management. Grasslands with higher N input showed lower F / B ratios. Grass-clover had a smaller fungal biomass and higher N leaching than grass. In general, a higher fungal biomass indicated a lower nitrogen leaching and a more negative partial N balance (or smaller N surplus), but more observations are needed to confirm the relationship between F / B ratio and sustainability.
Simplified denitrification models: overview and properties
Heinen, M. - \ 2006
Geoderma 133 (2006)3-4. - ISSN 0016-7061 - p. 444 - 463.
nitrous-oxide evolution - management model - winter-wheat - forest soils - potential denitrification - generalized-model - rainfall events - empirical-model - water-quality - n2o emissions
This paper reviews simplified process models for denitrification. More than fifty models were considered. The majority of these (simple) models are based on potential denitrification-either measured as a soil's property or computed from organic C dynamics-or consider denittification as a first-order decay process. As it is generally accepted that environmental soil conditions affect the denitrification process, reduction functions are used. Although denitrification is truly driven by the non-availability of oxygen, most authors argue that oxygen dynamics in soil is hard to simulate (or to measure). Therefore, water content is used as a complementary for oxygen diffusion. The higher the water content, the less oxygen will be present. Other factors that influence denitrification are nitrate-nitrogen content, soil temperature and soil acidity (pH). The availability of easily decomposable organic carbon determines the value of potential denitrification or the first-order decay rate constant. Although there seems to be consensus about the mathematical formulation of the simple process model, the shapes of the reduction functions differ largely between the models, especially for the water content reduction function. From a sensitivity analysis it follows that the model is most sensitive to the parameters of the water content reduction function, indicating that these parameters and the water content must be determined with great accuracy.
Effect of ectomycorrhizal fungi on the uptake of Ca, Mg and Al by Pinus sylvestris under aluminium toxicity
Schöll, L. van; Keltjens, W.G. ; Hoffland, E. ; Breemen, N. van - \ 2005
Forest Ecology and Management 215 (2005)1-3. - ISSN 0378-1127 - p. 352 - 360.
norway spruce seedlings - fungus suillus-variegatus - picea-abies seedlings - paxillus-involutus - mineral-nutrition - rigida seedlings - nutrient-uptake - critical loads - organic-acids - forest soils
Aluminium toxicity has been considered an important factor in forest decline. In earlier pot experiments, ectomycorrhizal tree seedlings were reported to have higher growth rates than non-mycorrhizal seedlings under aluminium toxicity. In this paper, we test that if this is caused by exclusion of Al and higher uptake of Ca and Mg by the ectomycorrhizal roots. Pinus sylvestris seedlings, grown for 3 months on a semi-hydroponic system, were continuously drip-irrigated with nutrient solution, containing 0 or 1.5 mM Al. The seedlings were non-mycorrhizal or colonized by ectomycorrhizal fungal species from a podzol soil. The presence of 1.5 mM Al in solution significantly decreased the dry weights of needles and roots compared to the control, and increased mycorrhizal colonization. Yet growth was not affected by mycorrhizal colonization. Concentrations of Al in the needles were significantly higher at 1.5 mM Al in solution than at 0 mM Al, and significantly higher in ectomycorrhizal seedlings than in non-mycorrhizal seedlings. Concentrations of Ca and Mg in the needles were significantly lower at 1.5 mM Al in solution than at 0 mM Al, but were not affected by ectomycorrhizal colonization. In conclusion, ectomycorrhizal colonization did not mitigate aluminium toxicity in our semi-hydroponic system. We suggest that better growth of soil-grown ectomycorrhizal tree seedlings compared to non-mycorrhizal tree seedlings should be explained by improved uptake of immobile nutrients such as P through a better soil exploration by the external mycelium or by detoxification of Al by organic anions excreted by the fungi
Podzolisation and soil organic matter dynamics
Buurman, P. ; Jongmans, A.G. - \ 2005
Geoderma 125 (2005)1-2. - ISSN 0016-7061 - p. 71 - 83.
methylation-mass spectrometry - podzol formation - southern queensland - chemical properties - size fractions - forest soils - bh horizons - aluminum - carbon - podzolization
Present models of podzolisation emphasize the mobilization and precipitation of dissolved organic matter. together with Al(-silicates) and Fe. Such models cannot explain the dominance of pellet-like organic matter in most boreal podzols and in well-drained podzols outside the boreal zone, and the discrepancy between the chemistry of percolating organic matter (DOC) and the organic matter accumulated in well-drained podzol-B horizons. The present paper offers an amended podzolisation theory, in which relative contribution of illuviated organic matter and root litter together with organic matter dynamics provide an explanation for the large variation in podzol morphology, It is suggested that fast organic matter dynamics as occurs on nutrient-rich parent materials in the boreal zone causes small accumulation of organic matter, mainly derived from roots. In such soils. the colors of Fe components dominate in the B horizon. Slow organic matter dynamics, as occurs on nutrient-poor parent materials and under hydromorphic circumstances, favors large organic matter accumulations in the B horizon. and a larger abundance of DOC-derived organic matter coatings. The latter group includes tropical podzols. (C) 2004 Elsevier B.V. All rights reserved.
Decomposition of 14C-labeled roots in a pasture soil exposed to 10 years of elevated CO2
Groenigen, C.J. van; Gorissen, A. ; Six, J. ; Harris, D. ; Kuikman, P.J. ; Groenigen, J.W. van; Kessel, C. van - \ 2005
Soil Biology and Biochemistry 37 (2005)3. - ISSN 0038-0717 - p. 497 - 506.
atmospheric carbon-dioxide - organic-matter dynamics - trifolium-repens l - microbial biomass - lolium-perenne - forest soils - tallgrass prairie - litter quality - fine roots - turnover
The net flux of soil C is determined by the balance between soil C input and microbial decomposition, both of which might be altered under prolonged elevated atmospheric CO2. In this study, we determined the effect of elevated CO2 on decomposition of grass root material (Lolium perenne L.). 14C-labeled root material, produced under ambient (35 Pa pCO2) or elevated CO2 (70 Pa pCO2) was incubated in soil for 64 days. The soils were taken from a pasture ecosystem which had been exposed to ambient (35 Pa pCO2) or elevated CO2 (60 Pa pCO2) under FACE-conditions for 10 years and two fertilizer N rates: 140 and 560 kg N ha¿1 year¿1. In soil exposed to elevated CO2, decomposition rates of root material grown at either ambient or elevated CO2 were always lower than in the control soil exposed to ambient CO2, demonstrating a change in microbial activity. In the soil that received the high rate of N fertilizer, decomposition of root material grown at elevated CO2 decreased by approximately 17% after incubation for 64 days compared to root material grown at ambient CO2. The amount of 14CO2 respired per amount of 14C incorporated in the microbial biomass (q14CO2) was significantly lower when roots were grown under high CO2 compared to roots grown under low CO2. We hypothesize that this decrease is the result of a shift in the microbial community, causing an increase in metabolic efficiency. Soils exposed to elevated CO2 tended to respire more native SOC, both with and without the addition of the root material, probably resulting from a higher C supply to the soil during the 10 years of treatment with elevated CO2. The results show the importance of using soils adapted to elevated CO2 in studies of decomposition of roots grown under elevated CO2. Our results further suggest that negative priming effects may obscure CO2 data in incubation experiments with unlabeled substrates. From the results obtained, we conclude that a slower turnover of root material grown in an `elevated-CO2 world¿ may result in a limited net increase in C storage in ryegrass swards.
Mapping coastal vegetation using an expert system and hyperspectral imagery
Schmidt, K.S. ; Skidmore, A.K. ; Kloosterman, E.H. ; Oosten, H. van; Kumar, L. ; Janssen, J.A.M. - \ 2004
Photogrammetric Engineering and Remote Sensing 70 (2004)6. - ISSN 0099-1112 - p. 703 - 715.
forest soils - salt-marshes - gis
Mapping and monitoring salt marshes in the Netherlands are important activities of the Ministry of Public Works (Rijkswaterstaat). The Survey Department (Meetkundige Dienst) produces vegetation maps using aerial photographs. However, it is a time-consuming and expensive activity. The accuracy of the conventional vegetation map derived using aerial photograph interpretation (API) is estimated to be approximately 43%. An alternative method is demonstrated that uses an expert system to combine airborne hyperspectral imagery with terrain data derived from radar altimetry. The accuracy of the vegetation map generated by the expert system increased to 66%. When hyperspectral imagery alone was used to classify coastal wetlands, an accuracy of 40% was achieved - comparable to the accuracy of the API-derived vegetation map. An analysis of the efficiency of the proposed expert system showed that the speed of map production is increased by using the new method. This means that digital image classification using the expert system is an objective and repeatable method superior to the conventional API method.
De bodemgesteldheid van bosreservaten in Nederland; deel 9 bosreservaat Leyduin-Vinkenduin (NH), bosreservaat Bunderbos (L), bosreservaat Ossenbos (G), bosreservaat Heloma- en Bleekerspolder(Fr), bosreservaat Achter de Voort (Ov), bosreservaat De Slikken van Flakkee (Z)
Mekkink, P. - \ 2004
Wageningen : Alterra (Alterra-rapport 60.9) - 88
beschermde bossen - bossen - bosgronden - bodemkarteringen - geologie - humus - bodemwater - nederland - bodemprofielen - kaarten - reserved forests - forests - forest soils - soil profiles - soil surveys - geology - humus - soil water - maps - netherlands
In de bosreservaten Leyduin-Vinkenduin, Bunderbos, Ossenbos, Heloma- en Bleekerspolder, Achter de Voort en Slikken van Flakkee komen Tertiaire, Pleistocene en Holocene afzettingen voor. Het zijn veengronden, moerige gronden, zandgronden, rivierkleigronden en lössgronden met daarin vlietveengronden, vlierveengronden, broekeerdgronden, veldpodzolgronden, haarpodzolgronden, vorstvaaggronden, duinvaaggronden, vlakvaaggronden, leekeerdgronden, ooivaaggronden en poldervaaggronden. De gronden komen voor met grondwatertrap Ia, IIa, IIb, IIIa, IIIb, IVu, Vao, Vbd, VIo en VId, VIId en VIIId. De verbreiding van de bodemeenheden en grondwatertrappen is bij de bosreservaten Leyduin-Vinkenduin, Bunderbos, Ossenbos en Achter de Voort weergegeven op een bodem- en grondwatertrappenkaart, schaal 1 : 5000. Mede onder invloed van het gevoerde beheer en het vegetatietype en hebben zich terrestrische en semiterrestrische humusprofielen ontwikkeld met een ectorganisch en een endorganisch deel. De profielopbouw en de opbouw van de strooisellaag zijn beschreven en in een database vastgelegd
Aluminium concentration versus the base cation to aluminium ratio as predictors for aluminium toxicity in Pinus sylvestris and Picea abies seedlings
Schöll, L. van; Keltjens, W.G. ; Hoffland, E. ; Breemen, N. van - \ 2004
Forest Ecology and Management 195 (2004)3. - ISSN 0378-1127 - p. 301 - 309.
norway spruce seedlings - gleditsia-triacanthos l - critical loads - root-growth - forest soils - calcium - magnesium - plants - inhibition - resistance
Aluminium (Al) toxicity is considered an important factor in forest deterioration caused by soil acidification. A ratio of base cations (BC) to Al in the soil solution lower than 1 is widely used as an indicator for potentially adverse effects on tree health. In our view, the validity of the assumptions underlying the use of the BC:AI ratio as an indicator for Al toxicity in trees has never been evaluated properly. Here, we evaluate the importance of the base cations Ca and Mg in counteracting Al toxicity. Pinus sylvestris and Picea abies seedlings were grown on nutrient solution with a range of Al (0-0.25-0.5-1-2 mM) and base cation (0.25-0.5-2 mM) concentrations, giving BC:Al ratios of 1 at different levels of Al. Increasing concentrations of Al in solution caused growth reductions, which could not be counteracted by increasing concentrations of BC in solution with P. sylvestris and only partly counteracted with P. abies. Increased concentrations of Al in solution decreased the concentrations in shoot and root of both Ca and Mg, while increased concentrations of BC in solution increased tissue concentrations of BC. Growth reductions were, however, not a result of BC deficiencies, as growth reduction already occurred in tree seedlings that maintained adequate concentrations of Ca and Mg. All growth and uptake variables measured showed a higher or equal correlation with the absolute concentrations of Al or Al + BC in solution than with the BC:Al ratio. We conclude that Al toxicity is determined solely by the concentration of Al in solution. Shoot growth decreased significantly as dissolved Al increased at a constant BC:Al ratio of 1. In P. abies, but not in P. sylvestris, dissolved BC can positively affect uptake of BC and growth, which might partly alleviate the toxic effects of Al. Our results show that the mechanistic explanation for the effect of the BC:Al ratio is insufficient to describe Al toxicity. Care should be taken when using models based on the BC:AI ratio to predict the effect of Al on tree growth. (C) 2004 Elsevier B.V. All rights reserved.
Bodem, humus en vegetatie onder verschillende loofboomsoorten op de stuwwal bij Doorwerth
Hommel, P.W.F.M. ; Waal, R.W. de - \ 2004
Wageningen : Alterra (Alterra-rapport 920) - 66
bossen - vegetatie - humus - tilia - ligstro - bosgronden - plantensuccessie - nederland - relaties - veluwe - bodem-plant relaties - natuurgebieden - forests - vegetation - humus - tilia - litter - forest soils - plant succession - netherlands - relationships - veluwe - soil plant relationships - natural areas
Dit rapport gaat in op de relatie tussen loofboomsoort, humus en ondergroei op een zwak lemige stuwwalbodem bij Doorwerth (Gelderland). Er werden opstanden vergeleken van linde, esdoorn, haagbeuk, eik en beuk. Onder invloed van het `rijke¿, goed verterende bladstrooisel van linde, esdoorn en haagbeuk bleek een ontwikkeling in de richting van een `rijker¿ bostype op gang te zijn gekomen. Alleen onder linde was echter binnen 40 jaar een goed ontwikkelde, soortenrijke Carpinion-vegetatie met meerdere oud-bossoorten ontstaan. De vegetatieontwikkeling onder linde lijkt wel sterk afhankelijk te zijn van de hoeveelheid licht die tot de bosbodem weet door te dringen.
De bodemgesteldheid van bosreservaten in Nederland; deel 8 bosreservaat Liefstinghsbroek
Mekkink, P. - \ 2003
Wageningen : Alterra (Alterra-rapport 60.8) - 50
bosgronden - beschermde bossen - bodemkarteringen - humus - grondwater - bodemprofielen - nederland - kaarten - groningen - forest soils - reserved forests - soil surveys - maps - humus - groundwater - soil profiles - netherlands - groningen
In het Groningse bosreservaat Liefstinghsbroek komen pleistocene fluvioperiglaciale afzettingen en dekzanden uit de Formatie van Twente en holocene afzettingen uit de Formatie van Singraven voor. Het zijn zandgronden en kleigronden met daarin veldpodzolgronden, laarpodzolgronden, gooreerdgronden, beekeerdgronden, broekeerdgronden en leekeerdgronden. De gronden komen voor met grondwatertrap Ia, IIa, IIb, IIIa, IIIb, Vao en Vbo,VIo en VId. De verbreiding van de bodemeenheden en grondwatertrappen is weergegeven op de bodem- en grondwatertrappenkaart, schaal 1 : 5000. Mede onder invloed van het gevoerde beheer en het vegetatietype hebben zich terrestrische en semi-terrestrische humusprofielen ontwikkeld met een ectorganisch en een endorganisch deel. De profielopbouw en de opbouw van de strooisellaag zijn beschreven en op tape vastgelegd.
De bodemgesteldheid van bosreservaten in Nederland; deel 7 bosreservaat Grootvenbos
Mekkink, P. - \ 2003
Wageningen : Alterra (Alterra-rapport 60.7) - 50
bosgronden - beschermde bossen - bodemkarteringen - humus - grondwater - bodemprofielen - nederland - kaarten - noord-brabant - forest soils - reserved forests - soil surveys - maps - humus - groundwater - soil profiles - netherlands - noord-brabant
In het Brabantse bosreservaat Grootvenbos komen pleistocene afzettingen uit de Formatie van Twente en holocene afzettingen uit de Formatie van Griendtsveen voor. Het zijn gedeeltelijk afgegraven hoogvenen met daarin vlietveengronden en vlierveengronden. De gronden komen voor met grondwatertrap wIa, wIIa, IIb, IIIb, Vao en Vbo. De verbreiding van de bodemeenheden en grondwatertrappen is weergegeven op de bodem- en grondwatertrappenkaart, schaal 1 : 5000. De dikte van het veen is, evenals de aard van de ondergrond, weergegeven op de veendiktekaart. Mede onder invloed van het gevoerde beheer en het vegetatietype hebben zich semi-terrestrische humusprofielen ontwikkeld met een ectorganisch en een endorganisch deel. Er komen boseerdmoders, veeneerdmodersmoerhydromullmoders, bosmesimors en gliedemesimors voor. De profielopbouw en de opbouw van de strooisellaag zijn beschreven en op tape vastgelegd.
Effects of elevated CO2 and N deposition on CH4 emissions from European mires
Silvola, J. ; Saarnio, S. ; Foot, J. ; Sundh, I. ; Greenup, A. ; Heijmans, M.M.P.D. ; Ekberg, A. ; Mitchell, E.P. ; Breemen, N. van - \ 2003
Global Biogeochemical Cycles 17 (2003)2 - 1068. - ISSN 0886-6236 - p. 37 - 1-37-12.
atmospheric carbon-dioxide - methane emissions - boreal mire - raised co2 - northern peatlands - water-table - nitrogen deposition - bog vegetation - forest soils - temperature
 Methane fluxes were measured at five sites representing oligotrophic peatlands along a European transect. Five study plots were subjected to elevated CO2 concentration (560 ppm), and five plots to NH4NO3 (3 or 5 g N yr(-1)). The CH4 emissions from the control plots correlated in most cases with the soil temperatures. The depth of the water table, the pH, and the DOC, N and SO4 concentrations were only weakly correlated with the CH4 emissions. The elevated CO2 treatment gave nonsignificantly higher CH4 emissions at three sites and lower at two sites. The N treatment resulted in higher methane emissions at three sites (nonsignificant). At one site, the CH4 fluxes of the N-treatment plots were significantly lower than those of the control plots. These results were not in agreement with our hypotheses, nor with the results obtained in some earlier studies. However, the results are consistent with the results of the vegetation analyses, which showed no significant treatment effects on species relationships or biomass production.
Bodemontwikkeling en nutriënten in het Smoddebos
Kemmers, R.H. ; Mekkink, P. - \ 2003
Wageningen : Alterra (Alterra-rapport 739) - 37
bossen - beschermde bossen - bosgronden - bodemprofielen - humus - bodemchemie - voedingsstoffen - nederland - overijssel - twente - forests - reserved forests - forest soils - soil profiles - humus - soil chemistry - nutrients - netherlands - overijssel - twente
Het Smoddebos (Ov) is een rijk bossysteem op keileemgrond met Gt V. In een transsect door een vochtig en een droog bosgedeelte is het humusprofiel beschreven en bodemchemisch onderzocht. De zuur/basen- en de voedingstoestand van de bodem zijn bepalend voor het humusvormtype en kunnen worden verklaard uit een lokaal infiltratie-kwelsysteem. Middenop de rabatten komen matig zure, ijzerarme en matig voedelrijke standplaatsen voor. Langs de greppels zijn basen- en ijzerrijkere condities aanwezig met een goede vertering van organische stof en voedselrijkere omstandigheden. In het droge transsect II is het effect van begreppeling vrijwel afwezig, is de bodem zeer zuur en voedselarmer. In transsect I is een natuurlijk proces van verzuring gaande, terwijl in transsect II de zure omstandigheden zijn ontstaan door grondbewerking. De koolstof-, stikstof- en fosforvoorraad in de transsecten bedraagt gemiddeld resp. 9,8-14,2 kg, 0,91-1,02 kg en 87-110 g per m2. Door bevloeiing in het verleden is de koolstof- en fosforvoorraad in de bodem van transsect II significant groter dan in die van transsect I. Binnen de transsecten varieert de voorraad sterk.
Rijke bossen op arme bodems; alternatieve boomsoortenkeuze verhoogt soortenrijkdom ondergroei op verzuringgevoelige gronden
Hommel, P.W.F.M. ; Waal, R.W. de - \ 2003
Landschap : tijdschrift voor landschapsecologie en milieukunde 20 (2003)4. - ISSN 0169-6300 - p. 193 - 204.
bodemchemie - humus - bosgronden - bodemaciditeit - habitats - bosstrooisel - bostypen - bosopstanden - soil chemistry - humus - forest litter - forest soils - soil acidity - habitats - forest types - forest stands
Aanplant van gemengde opstanden, hoogdunning, creëren van open plekken, bosbegrazing, 'niets-doen' en dood hout laten liggen: het zijn allemaal maatregelen die bijdragen aan een gevarieerder bosecosysteem. In dit artikel wordt aangegeven dat een alternatieve boomsoortensamenstelling hier een extra dimensie aan kan toevoegen
Assessment of the dynamics in nitrogen and carbon sequestration of European forest soils
Vries, W. de; Salm, C. van der; Reinds, G.J. ; Dise, N.B. ; Gundersen, P. ; Erisman, J.W. ; Posch, M. - \ 2003
Wageningen : Alterra (Alterra-rapport 818) - 147
koolstof - stikstof - bosgronden - uitspoelen - depositie - beoordeling - modellen - bossen - europa - carbon - nitrogen - forest soils - leaching - deposition - assessment - models - forests - europe
This report describes the major result of a research project that focused on the assessment of the dynamics in nitrogen and carbon sequestration of European forest soils by estimation of the: (i) retention or release of nitrogen species for selected Intensive Monitoring plots by comparing the input, based on measurements of throughfall and bulk deposition, with the soil output, obtained by multiplying soil solution concentration measurements with modelled soil water fluxes and (ii) carbon sequestration by relating the N and C dynamics in soils by the soil C/N ratio. Major results are that: (i) N leaching and sequestration is influenced by the soil C/N ratio in the organbic layer, (ii) C sequestration in forest soils on a European scale is much less than C sequetration due to forest growth and (iii) the impact of N deposition on soil N leaching is fast but the impact on changes in soil C/N ratio is small.
Oude lindenbossen op Jutland; referentiebeelden voor bosontwikkeling in Nederland?
Hommel, P.W.F.M. ; Waal, R.W. de; Spek, T. - \ 2003
Nederlands Bosbouwtijdschrift (2003)2. - ISSN 0028-2057 - p. 13 - 21.
bossen - bosbomen - tilia - bosecologie - opstandsstructuur - opstandskenmerken - ecosystemen - plantenecologie - vegetatie - botanische samenstelling - bosgronden - onderlaag - bosstrooisel - bodemvorming - denemarken - forests - forest trees - tilia - forest ecology - stand structure - stand characteristics - ecosystems - plant ecology - vegetation - botanical composition - forest soils - understorey - forest litter - soil formation - denmark
In het kader van het Alterra-onderzoeksproject 'boomsoortkeuze op verzuringsgevoelige bodem' werden in Jutland vijf lindenbossen bezocht, die als referentiebeeld kunnen fungeren voor bosecosystemen op de Nederlandse pleistocene zandgronden. De winterlinde kan hier een belangrijke rol spelen in de ontwikkeling van natuur- en multifunctionele bossen. Een beschrijving van de bosgebieden, met vooral aandacht voor de relatie boomsoort-strooisellaag-ondergroei, hydrologie, verjonging en vraat, 'verbeuking' en menging