Natürlicher gehalt und anthropogene anreicherung von Schwermetallen in den Sedimenten von Elbe, Eider, Trave und Schwentine     

Rudolf Lichtfuß  Gerhard Brümmer 《CATENA》1981,8(3-4)

The sediments of four rivers in Northern Germany were analysed for heavy metals. 371 sediment samples were taken from 24 investigation sites of the rivers Elbe, Eider, Trave and Schwentine and from North Sea tidal flat areas. Within each investigation site strong positive relationships exist between the heavy metal contents and the contents of the fine size fractions < 2 μm and < 20 μm of the sediments. To compare the metal contents in the sediments from different areas, differences in grain size were eliminated by computing the metal contents for a clay content of 25% by means of regression equations.The fluvial sediments at a few inland investigation sites, as well as the tidal flat sediments are not detectably polluted with heavy metals. Their metal contents could be used as background values for computing enrichment factors of polluted fluvial deposits.Sediments from the river Elbe in and upstream of the port of Hamburg, and from some parts of the rivers Eider and Trave near industrial and densely populated districts, are highly enriched with heavy metals. The highest enrichment factors are for Hg 85, Cd 56, Pb 37, Cu 34, Zn 29, As 19, Cr 6, Ni 4 and Co 3 times the background values.The ecological importance of the heavy metal contents in the sediments is discussed.  相似文献   

Simplified N fertilization strategies for winter wheat. Part 1: plants: compensation capacity of modern wheat varieties     

Thomas Makary  Rudolf Schulz  Torsten Müller  Carola Pekrun 《Archives of Agronomy and Soil Science》2020,66(6):847-857

ABSTRACT

Winter wheat in northwestern Europe is often fertilized with several doses of calcium-ammonium-nitrate (CAN). For economy, farmers fertilize using a combination of N-doses. Here, we examined the necessity of N splitting (1–3) and application timing in experiments conducted in 2010 using a one-factorial fully randomized block design, and in 2011–2012 using a two-factorial split-plot design (four replicates). The study site, in southwestern Germany, had silty loam soil, and modern cultivars (2010: one cultivar, 2011–2012: three cultivars) with different genetic abilities to develop the yield components of interest were tested. A late first or single N application at stage BBCH 29/31 did not lead to differences in grain yields or protein contents compared to three N applications. However, a single N application at stage BBCH 25/27 resulted in a reduced protein content. Yield component development did not significantly differ among the cultivars. Early N application increased plant density but not yield. In two years, low plant densities were compensated by higher numbers of kernels per spike. Hence, under the tested conditions, the number of N applications could be reduced, as the high compensation ability of modern cultivars allows N fertilization consisting of two or even one application.  相似文献   

Methods for evaluating human impact on soil microorganisms based on their activity,biomass, and diversity in agricultural soils   总被引：10，自引：0，他引：10  

Rainer Georg Joergensen  Christoph Emmerling 《植物养料与土壤学杂志》2006,169(3):295-309

The present review is focused on microbiological methods used in agricultural soils accustomed to human disturbance. Recent developments in soil biology are analyzed with the aim of highlighting gaps in knowledge, unsolved research questions, and controversial results. Activity rates (basal respiration, N mineralization) and biomass are used as overall indices for assessing microbial functions in soil and can be supplemented by biomass ratios (C : N, C : P, and C : S) and eco‐physiological ratios (soil organic C : microbial‐biomass C, qCO₂, qN_min). The community structure can be characterized by functional groups of the soil microbial biomass such as fungi and bacteria, Gram‐negative and Gram‐positive bacteria, or by biotic diversity. Methodological aspects of soil microbial indices are assessed, such as sampling, pretreatment of samples, and conversion factors of data into biomass values. Microbial‐biomass C (µg (g soil)^–1) can be estimated by multiplying total PLFA (nmol (g soil)^–1) by the F_PLFA‐factor of 5.8 and DNA (µg (g soil)^–1) by the F_DNA‐factor of 6.0. In addition, the turnover of the soil microbial biomass is appreciated as a key process for maintaining nutrient cycles in soil. Examples are briefly presented that show the direction of human impact on soil microorganisms by the methods evaluated. These examples are taken from research on organic farming, reduced tillage, de‐intensification of land‐use management, degradation of peatland, slurry application, salinization, heavy‐metal contamination, lignite deposition, pesticide application, antibiotics, TNT, and genetically modified plants.  相似文献   

Mycorrhizal colonization and lead distribution in root tissues of Norway spruce seedlings     

Georg Jentschke  Eberhard Fritz  Petra Marschner  Christine Rapp  Volkmar Wolters  Douglas L. Godbold 《植物养料与土壤学杂志》1997,160(2):317-321

Non-inoculated spruce seedlings (Picea abies Karst.) and spruce seedlings colonized with Lactarius rufus Fr., Pisolithus tinctorius Coker & Couch or Paxillus involutus Fr. were grown for 35 or 37 weeks in a microcosm system on two types of natural forest humus differing in Pb content. Using X-ray microanalysis, the distribution and content of Pb in the tissues of mycorrhizal and non-mycorrhizal root tips were compared. No significant difference in the Pb contents of root cortex cell walls of non-mycorrhizal and seedlings colonized by Lactarius rufus, Pisolithus tinctorius, or indigenous mycorrhizal fungi (mainly Tylospora sp.) was found. However, in root tips of seedlings colonized by Paxillus involutus, due to a higher binding capacity for cations, the Pb content in cell walls of the root cortex were higher than in non-mycorrhizal roots. Pb contents in cell walls of the cortex of mycorrhizal and non-mycorrhizal roots were 3 times higher in plants growing in humus with a high Pb content than in plants growing in humus with a low Pb content. It is concluded that increasing contents of Pb in the organic matter may lead to an increased loading of the apoplast with Pb. The mycobionts tested in this investigation did not exclude Pb from root tissues.  相似文献   

Importance of reservoirs for the conservation of freshwater molluscs in a tropical urban landscape     

Reuben Clements  Lian Pin Koh  Rudolf Meier 《Biological conservation》2006,128(1):136-146

Freshwater species and ecosystems are gravely imperiled, particularly within urban landscapes of tropical Asia. In one of the region’s most urbanized landscapes (i.e., Singapore), we determined: (1) the importance of six different habitats (i.e., catchment reservoirs, estuarine reservoirs, forest streams, rural streams, ponds and monsoon canals) for conserving the diversity of freshwater molluscs; (2) key environmental factors (e.g., pH) affecting molluscan distribution; (3) important biogeographical determinants (e.g., area) of molluscan richness within each habitat; and (4) the habitat affinities of introduced species. High sampling saturation was achieved at most study habitats with minimal sampling effort, suggesting that the utilization of molluscs as bioindicators can expedite freshwater conservation initiatives. Estuarine reservoirs (6.0 ± 2.0) had the highest molluscan richness, vis-à-vis catchment reservoirs, forest streams, rural streams, ponds and monsoon canals (3.0 ± 1.5; 0; 3.3 ± 2.0; 1.8 ± 0.5 and 3.5 ± 0.5 respectively). Both reservoir types possessed species compositions distinct from other habitats and contained majority (76%) of the sampled species. Reservoirs therefore serve to conserve the bulk of local freshwater malacofauna, especially if they are maintained at near-neutral pH levels (i.e., ∼7.3) and contain large substrates (i.e., rocks). Area was the best predictor of molluscan richness across all habitats, implying that larger freshwater habitats require higher conservation priorities than smaller ones. Introduced (non-native) species (e.g., Pomacea canaliculata) had high affinities for reservoirs, which are in need of monitoring to curb population expansions. The interminable growth of human settlements urgently requires a reconciliatory approach, which includes the ecologically-sound design and management of modified habitats to complement reserves in sustaining native freshwater species.  相似文献   

The problem of pretreatment and unintentional variations in the fumigation-extraction method for time-course measurements in the field     

Torsten Mueller  Momoh F. E. Lavahun  Rainer Georg Joergensen  Brunk Meyer 《Biology and Fertility of Soils》1996,22(1-2):167-170

A control soil stored at 4°C was analyzed 38 times by fumigation-extraction during a period of 11 months to correct for variations caused by the analytical procedure. The difference in extractable C between fumigated and unfumigated samples oscillated around the average without a positive or negative trend. When data from contemporaneously extracted field samples were corrected with control soil data the variations were lowered. The deviations between corrected and uncorrected biomass C values had maxima of ±12%. Data obtained for seven dates using pre-extraction, wet-sieving, and centrifuging were compared with data obtained by the conventional procedure without any pretreatment. A negative difference from data obtained without pretreatment was found when the soil water content was decreased to 6%. The largest positive difference (+38%) was found in May during the period of highest root growth.  相似文献   

Resistenzeigenschaften im Gersten- und Weizensortiment Gatersleben     

Ilse Nover  Rudolf Mansfeld 《Genetic Resources and Crop Evolution》1959,7(1):29-36

Ohne Zusammenfassung  相似文献   

Babesia microti (Piroplasmida: Babesiidae) in nymphal Ixodes ricinus (Acari: Ixodidae) in the Czech Republic     

Rudolf I  Golovchenko M  Sikutová S  Rudenko N  Grubhoffer L  Hubálek Z 《Folia parasitologica》2005,52(3):274-276

A total of 350 nymphs of the common tick Ixodes ricinus (Linnaeus, 1758) were collected in an endemic focus of Lyme borreliosis (South Moravia, Czech Republic) and examined for the presence of the protozoan Babesia microti (Fran?a, 1909) by polymerase chain reaction (PCR), using primers specific for the B. microti gene encoding small subunit rRNA. The assay revealed five positive pools (out of 70 pools examined); the corresponding prevalence rate was about 1.5%. Sequence analysis of the PCR products confirmed their 100% homology with that of B. microti. The study represents the first evidence of B. microti in ixodid ticks in the Czech Republic.  相似文献   

Epidemiological investigations of bovine Chorioptes mange in Germany     

Beck W  Pfister K  Weiland G 《Berliner und Münchener tier?rztliche Wochenschrift》2005,118(3-4):128-133

Chorioptic mange in cattle has long been recognised as a common external parasitosis in livestock. In order to evaluate the economic importance of Chorioptes bovis-mange, the seasonal prevalence in several types of husbandry in the states of Germany, location of clinical skin symptoms, procedure of diagnosis, influence on milk or meat production, and treatment especially in dairy farming, 1190 German large animal practicioners have been asked by questionnaires from which 367 responded. This paper gives an update on important epidemiological investigations on bovine chorioptic mange due to this inquiry. Since more than one third of the questioned veterinarians see tail mange often, it is of high importance for farm cattle. Chorioptes mange mainly occurs in dairy cattle stocks, and has especially negative effects on milk production and meat productivity. For treatment of this external parasitosis mainly macrocyclic lactons and pyrethroids are used.  相似文献   

Racing, ornamental and city pigeons carry shiga toxin producing Escherichia coli (STEC) with different Shiga toxin subtypes, urging further analysis of their epidemiological role in the spread of STEC     

Grossmann K  Weniger B  Baljer G  Brenig B  Wieler LH 《Berliner und Münchener tier?rztliche Wochenschrift》2005,118(11-12):456-463

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