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1.
Stabilization mechanisms of organic matter in four temperate soils: Development and application of a conceptual model 总被引:2,自引:0,他引:2
Margit von Lützow Ingrid Kögel‐Knabner Bernard Ludwig Egbert Matzner Heinz Flessa Klemens Ekschmitt Georg Guggenberger Bernd Marschner Karsten Kalbitz 《植物养料与土壤学杂志》2008,171(1):111-124
Based on recent findings in the literature, we developed a process‐oriented conceptual model that integrates all three process groups of organic matter (OM) stabilization in soils namely (1) selective preservation of recalcitrant compounds, (2) spatial inaccessibility to decomposer organisms, and (3) interactions of OM with minerals and metal ions. The model concept relates the diverse stabilization mechanisms to active, intermediate, and passive pools. The formation of the passive pool is regarded as hierarchical structured co‐action of various processes that are active under specific pedogenetic conditions. To evaluate the model, we used data of pool sizes and turnover times of soil OM fractions from horizons of two acid forest and two agricultural soils. Selective preservation of recalcitrant compounds is relevant in the active pool and particularly in soil horizons with high C contents. Biogenic aggregation preserves OM in the intermediate pool and is limited to topsoil horizons. Spatial inaccessibility due to the occlusion of OM in clay microstructures and due to the formation of hydrophobic surfaces stabilizes OM in the passive pool. If present, charcoal contributes to the passive pool mainly in topsoil horizons. The importance of organo‐mineral interactions for OM stabilization in the passive pool is well‐known and increases with soil depth. Hydrophobicity is particularly relevant in acid soils and in soils with considerable inputs of charcoal. We conclude that the stabilization potentials of soils are site‐ and horizon‐specific. Furthermore, management affects key stabilization mechanisms. Tillage increases the importance of organo‐mineral interactions for OM stabilization, and in Ap horizons with high microbial activity and C turnover, organo‐mineral interactions can contribute to OM stabilization in the intermediate pool. The application of our model showed that we need a better understanding of processes causing spatial inaccessibility of OM to decomposers in the passive pool. 相似文献
2.
We aimed to find critical spatial distances (as an input quantity for the Knox's test) using geostatistical methods. The spatiotemporal data set included all individual-chamois cases of scabies observed in Styrian chamois populations in 137 of 2837 game preserves in Styria (a province in the south of Austria) over the time period between 1952 and 1998. Theoretical variogram models were fitted to empirical variograms, which were calculated for cycles of 5 years. The unit of analysis was the mean quadratic deviation between individual-chamois cases of scabies. The "range" (which represents the transition from the state in which spatial correlation exists to the state in which there is absence of spatial correlation) was used as an indicator for the critical spatial distance for the Knox's test. The critical distances for the 5-year cycles varied between 10.8 and 16.0 km. If the time of observation is not considered, the critical "overall" distance amounted to 13.5 km. 相似文献
3.
4.
An integrative approach of organic matter stabilization in temperate soils: Linking chemistry,physics, and biology 总被引:1,自引:0,他引:1
Ingrid Kögel‐Knabner Klemens Ekschmitt Heinz Flessa Georg Guggenberger Egbert Matzner Bernd Marschner Margit von Lützow 《植物养料与土壤学杂志》2008,171(1):5-13
With this topical issue, we present the work of the Priority Program 1090 of the German Research Foundation (“Deutsche Forschungsgemeinschaft DFG”): “Soils as a source and sink for CO2 – mechanisms and regulation of organic matter stabilisation in soils”. This introduction gives an overview on the sites investigated and the major research approaches, including a glossary of major terms used in the field of soil organic matter research. We point out the advantages of integration of data from a broad field of different soil‐science disciplines and the progress achieved by application and combination of new analytical methods describing the quality and turnover of soil organic matter. 相似文献
5.
Eckhardt P Fuchs K Kornberger B Köfer J 《Berliner und Münchener tier?rztliche Wochenschrift》2010,123(11-12):468-476
Over a period of 22 months 13 official meat inspection authorities examined a number of 152 520 swine at an Austrian slaughterhouse for pathologic-anatomic changes (five parameters). Of those veterinarians whose reliability in the recording of findings was a given, the results were analysed by employing a mathematical model which assessed whether the activities of 25 attending veterinarians and 223 farmers actually lead to an improvement of animal health in their livestock. Mild pneumonia was registered in 14.5% of swine; no attending veterinarians had any influence whatsoever on the occurrence of this parameter. Farmers' activities improved animal health on two farms (0.9%), six farms of origin (2.69%) showed significantly lower findings than the average of all farms. Pleurisy was ascertained in 22% of all slaughter pigs. Through measures taken, four attending veterinarians (16%) caused a reduction of incidents, two works managers (0.9%) made worse, six farmers (2.69%) improved animal health of their live stock. Seven farmers (3.14%) showed significantly (p < 0.05) higher, 28 farms (12.6%) lower prevalence. Pericarditis affected 4.5% of the animals in question. On all farms of origin the condition of health remained unchanged by measures taken by veterinarians. On two farms (0.9%) the influence exercised by farmers led to a deterioration of the health of swine, six businesses (2.69%) showed higher, one (0.45%) lower prevalence than on average. 6.2% of swine showed white spots. Attending veterinarians did not influence this parameter at all. With preventive measures taken five farms (2.24%) showed less, three farms (1.35%) higher prevalence by the end of the 22 month term. Mange concerned 2.2% of all slaughter pigs. The activities of one veterinarian (4%) caused the number of incidents to double; on six farms (2.69%) a significantly higher prevalence was registered. Whatever influence exercised, the status of health of slaughter pigs remained unchanged throughout the duration of the study. 相似文献
6.
Deutz A Fuchs K Schuller W Nowotny N Auer H Aspöck H Stünzner D Kerbl U Klement C Köfer J 《Berliner und Münchener tier?rztliche Wochenschrift》2003,116(7-8):306-311
The aim of this study was to investigate the seroprevalences to zoonotic pathogens in hunters, to propose preventive measures and to obtain more information about the occurrence of zoonotic pathogens in local wild animal populations. From 146 male and 3 female hunters originating from the south-eastern Austrian federal states of Styria and Burgenland blood samples were taken and anamnestic data were obtained using a questionnaire. The serological investigations included the following viral, bacterial and parasitic zoonotic agents or zoonoses, respectively (antibody-seroprevalences in brackets): encephalomyocarditis virus (EMCV, 15%), Puumala-Hantavirus (10%), Newcastle Disease virus (NDV, 4%), borreliosis (IgG 42%, IgM 7%), brucellosis (1%), chlamydiosis (3%), ehrlichiosis (IgG 15%, IgM 3%), leptospirosis (10%), tularaemia (3%), Q fever (0%), Echinococcus multilocularis/E. granulosus (5%/11%), toxocariasis (17%). Out of a control group of 50 persons (urban population, no hunters) only one person was found to be seropositive for Toxocara canis and NDV and four for EMCV, all other results were negative in the control group. The high seroprevalences especially to Borrelia burgdorferi s.l., Ehrlichia spp., Leptospira interrogans, E. granulosus, E. multilocularis, encephalomyocarditis virus and Puumala virus demonstrate that hunters are particularly exposed to zoonotic pathogens. It should also be noted that one hunter was seropositive for Brucella abortus and five exhibited antibodies to Francisella tularensis. In these cases, as well as in the cases of the 15 seropositives for Leptospira interrogans, the suspected source of infection may--besides rodents--also include wild boars and brown hares. The infections with NDV and Chlamydophila psittaci may be traced back to contact with certain species of birds (potential risk: aviaries). For Hantaviruses, rodents are considered to be the main source of human infections. 相似文献
7.
Effect of historic landscape change on the genetic structure of the bush-cricket Metrioptera roeseli
Stephanie I. J. Holzhauer Klemens Ekschmitt Anna-Christine Sander Jens Dauber Volkmar Wolters 《Landscape Ecology》2006,21(6):891-899
This study investigates the impact of past and present landscape structure on the current genetic structure of the bush-cricket
Metrioptera roeseli (Orthoptera, Tettigoniidae) in a rural landscape in Germany. Assuming that land-use types, such as grassland, arable land
and forest, as well as linear structures, mainly roads, differentially affect the connectivity of the bush-cricket's habitat
and therefore migration and gene flow, we correlated landscape parameters between sampling locations as derived from GIS-maps
with genetic similarities between individual bush-crickets as estimated by RAPD-PCR. Fifty bush-crickets were sampled with
distances between sampling locations varying between 15 m and 2 km. Corresponding landscape configurations were recorded in
8 years between 1945 and 1998. Landscape configuration 50 years ago appeared to have influenced the present genetic structure
of the bush-cricket (R
2 = 0.18). Crossing roads and land use other than grassland along the transect between sampling locations tended to decrease
genetic similarity, whereas grassland and parallel roads tended to increase genetic similarity between bush-crickets. Following
shifts in land use during 1953–1973 the correlation between landscape and present genetic structure decreased gradually. Our
study suggests that it needs time for the landscape to build a visible effect on the genetic structure of the bush-cricket
population, and that this effect cannot be detected if the landscape changes faster than the genetic structure responds to
it. 相似文献
8.
Ilja Sonnemann Hülya Dogan Annette Klein Barbara Pieper Klemens Ekschmitt Volkmar Wolters 《植物养料与土壤学杂志》1999,162(4):385-391
The effect of increasing nematode abundance on microbial biomass and activity in a temperate grassland soil was investigated in a microcosm experiment. The experiment lasted for 33 days. The natural nematode diversity, as well as relevant aspects of the spatial heterogeneity of the soil microhabitat in a 80 m2 sampling area were maintained in the microcosms. No correlation was found between nematode abundance and microbial biomass (CFE) or ergosterol content (as a measure of active fungal biomass). However, a doubling of nematode abundance reduced CO2 production by 11 % and increased bacterial substrate utilization (BIOLOG) by 18 %. A possible explanation is that fungal activity was strongly reduced at higher nematode density, overcompensating the simultaneous increase in bacterial activity. The results show that the nematode community in a grassland soil is capable of causing a considerable shift in soil microbial activities towards an increased bacterial metabolism, overriding the spatial heterogeneity of the soil habitat and the taxonomic diversity of the community itself, and thereby producing functional effects relevant at spatial scales that far exceed the activity domains of the organisms involved. 相似文献
9.
Earthworm effects on the use of C sources by microorganisms: Non-linear response to temperature alteration 总被引:1,自引:0,他引:1
A microcosm was used to study the effect of the endogeic earthworm Aporrectodea caliginosa (Savigny) on the use of C by microorganisms in a calcareous beech forest soil and its dependence on temperature (5–25%C). Inclusion of 14C-labelled beech leaf litter made it possible to differentiate between C use by litter-colonizing microflora and by autochthonous soil microflora. The effect of temperature on the soil microbial biomass 12C was confined to a significant increase at 15 and 20°C. The size of the 14C-labelled microbial biomass, in contrast, was positively correlated with temperature. The 12C mineralization increased exponentially with temperature. The relationship between 14C mineralization and temperature, in contrast, followed a logistic curve. Significant main effects of A. caliginosa were confined to 12C mineralization, reflecting an increase in 12CO2–C production in the earthworm treatments. The earthworm effects on 12CO2–C production and on 14C incorporation of the microflora were not linear. The effect of A. caliginosa on 12CO2–C production was most pronouned at intermediate temperatures. It is concluded that temperature alterations affect the microbial use of different C sources in different ways and that the temperature effects can be significantly modified by endogeic earthworms. 相似文献
10.
Thomas K. Gottschalk Tim Diekötter Klemens Ekschmitt Bernd Weinmann Friedrich Kuhlmann Tobias Purtauf Jens Dauber Volkmar Wolters 《Landscape Ecology》2007,22(5):643-656
Agricultural management is a major factor driving the change of faunal richness in anthropogenic landscapes. Thus, there is
an urgent need to develop tools that allow decision-makers to understand better intended and unintended effects of agricultural
policy measures on biodiversity. Here we demonstrate the potential of such a tool by combining a socio-economic model with
the biodiversity model GEPARD to forecast the response of bird and carabid species richness to two scenarios of agricultural
subsidies: (1) subsidies based on production levels and prices and (2) direct income support that is independent of production
levels. We focussed on farmland of the Lahn-Dill area, Germany, as an example of European regions with low intensity farming.
GEPARD predicts faunal richness and is based on multi-scaled resource-selection functions. Under both scenarios the area of
predicted losses in species richness of birds and carabids was larger than the area of predicted gains in species richness.
However, the area with predicted losses of avian richness was smaller under the direct income support scenario than under
the production-based subsidy scenario, whereas the area with predicted losses of carabid species richness was smaller under
the production-based subsidy scenario than under the direct income support. Yet locally, richness gains of up to four species
were predicted for carabids under both scenarios. We conclude that the sometimes contrasting and heterogeneous responses of
birds and carabids at different localities suggest the need for spatially targeted subsidy schemes. With the help of the GIS-based
approach presented in this study, prediction maps on potential changes in local and regional species richness can be easily
generated. 相似文献