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1.
Anette Amtmann Ibrahim Ahmed Petra Zahner-Rimmel Adam Mletzko Lisa Katharina Jordan Martin Oberle Helmut Wedekind Jürgen Christian Sven Michael Bergmann Anna Maria Becker 《Journal of fish diseases》2020,43(2):185-195
In a search for alternative, environmentally friendly and effective disinfecting agents, a commercially available protease—Neutrase®—was tested in this work for inactivation of koi herpesvirus (KHV) and of viral haemorrhagic septicaemia virus (VHSV). For comparison, the stability of these viral pathogens in similar configurations at various pH values and concentrations of peracetic acid or quicklime, typically used for disinfection, was tested. Therefore, virus suspensions were incubated with various concentrations of different agents for 24 hr and the titre of the remaining infectious particles was determined by virus titration. Furthermore, the treatment of both viruses, with the agents at concentrations that were previously appointed as effective, was also examined in the presence of solid material (quartz sand). All procedures investigated in this study, including the protease treatment, were able to reduce the titre of KHV and VHSV below the detection limit of the titration. Although further studies are necessary, this is the first report of the application of a protease for the inactivation of the selected fish pathogens, demonstrating the great potential of the latter for disinfection. 相似文献
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Helmut Brandl 《Small-Scale Forestry》2006,5(1):145-159
Today the Black Forest is an internationally renowned tourist region in Germany. For centuries the Black Forest remained as
a low mountain range regarded as not suitable for settlement due to its unfavourable climatic conditions and difficult terrain.
Clearing the dense forests and settlement therefore started at a historically late stage compared to other regions of Germany,
about 1000 years ago. Due to the special conditions in this area, the structure of the settlement had to be quite different
to those landscapes with more favourable conditions for agriculture. A single-farm settlement developed, farms situated 200
to 400 m away from each other, surrounded by meadows, agricultural land and forests and owned by the farmer’s family. This
structure has remained in some areas until today; in other areas different types of settlement took place, and great changes
occurred during history. A special type of agroforestry — a slash-and-burn-management of forests — also took place 150 to
200 years ago. 相似文献
5.
Ohne Zusammenfassung 相似文献
6.
Thomas?HolstEmail author Helmut?Mayer Dirk?Schindler 《European Journal of Forest Research》2004,123(1):13-28
Within the framework of an interdisciplinary project on the effects of climate and forest management on beech-dominated deciduous forests (Swabian Jura, south-western Germany), forest meteorological investigations are carried out to analyse the influences of exposure and canopy density on the microclimate within various beech stands (Fagus sylvatica L.). This second paper of the series Microclimate within beech stands focuses on the thermal conditions that exist mainly in the near-surface layer at different test plots. They were analysed by air temperature, Ta, (at 1.5 m a.g.l) and soil temperature, Ts, at six depths measured continuously in the period 1999–2003. The main results can be summarized as follows. (1) The thermal situation within the beech stands described by Ta depended primarily on the turbulent air-mass exchange conditions which were based on the slope-specific energy balance of the forest floor and advective heat fluxes. (2) The thermal situation within the soil described by Ts at 3 and 20 cm depth was governed by the molecular heat transport. Therefore, the heating and cooling rates of Ts were always lower than for Ta. Higher Ta and Ts values for the test plots on the SW slope showed that the thermal conditions within the beech stands depended primarily on the exposure. (3) Based on slope-specific differences of daily extremes of Ta and Ts at 3 cm depth between the silviculturally treated and control plots, the influence of the more pronounced height growth of the understorey vegetation under the near-surface thermal conditions could be clearly verified for the NE slope.Abbreviations PAR Photosynthetically active radiation - PAI Plant area index - LAI Leaf area index 相似文献
7.
Richter Jana Baltruschat Helmut Kabrodt Kathrin Schellenberg Ingo 《植物病害和植物保护杂志》2011,118(3-4):109-118
Journal of Plant Diseases and Protection - The importance of herbal plants is evident in the prevalent use as flavoring ingredients in food. However, meeting the growing demand for organic grown... 相似文献
8.
Helmut Saucke Britta Schultz Rainer Wedemeyer Nadine Liebig Olaf Zimmermann Peter Katz 《Gesunde Pflanzen》2011,63(4):183-189
The cabbage whitefly,Aleyrodes proletella, has developed to a key pest in brassica vegetable crops throughout Germany. In a 3-year project we investigated a biotechnical approach employing netting (0.8?×?0.8 mm meshsize) in combination with the native parasitoidEncarsia tricolor in an inoculative-inundative approach in organic Brussels sprouts under field conditions. In small scale plot experiments continuous netting from transplanting in May till October alone reduced whitefly larval densities by 77 % at peak infestation in all years. Remaining whitefly infestation under net was associated with the necessity of temporary net removal for the purpose of mechanical weeding, which caused primary whitefly infestation. Release of mass rearedE. tricolour under net at the first signs of larval infestation significantly increasedA. proletella-parasitation and reduced infestation compared to netted controls without release. Furthermore, at highest dosage in 2009,E. tricolor had a significant enhancing effect on raw yield and the quality level of marketable yield. Additional on-farm experiments without netting in 2008 and 2009 confirmed the control potential ofE. tricolor. Although the most important project mile stones have been achieved, namely (a)E. tricolour-establishment under net and in the open field, (b) enhanced parasitation corresponding with pest density decline and (c) a positive impact on yield and quality parameters, further research will be necessary. The focus should be on the initial infestation period, optimizing the timing, frequency and required dosage. 相似文献
9.
Sibylle K. Hassler Beate Zimmermann Michiel van BreugelJefferson S. Hall Helmut Elsenbeer 《Forest Ecology and Management》2011,261(10):1634-1642
Landscapes in the humid tropics are undergoing a continuous change in land use. Deforestation is still taking its toll on forested areas, but at the same time more and more secondary forests emerge where formerly agricultural lands and pastures are being abandoned. Regarding soil hydrology, the extent to which secondary succession can recover soil hydrological properties disturbed by antecedent deforestation and pasture use is yet poorly understood. We investigated the effect of secondary succession on saturated hydraulic conductivity (Ks) at two soil depths (0-6 and 6-12 cm) using a space-for-time approach in a landscape mosaic in central Panama. The following four land-use classes were studied: pasture (P), secondary forest of 5-8 years of age (SF5), secondary forest of 12-15 years of age (SF12) and secondary forest of more than 100 years of age (SF100), each replicated altogether four times in different micro-catchments across the study region. The hydrological implications of differences in Ks in response to land-use change with land use, especially regarding overland flow generation, were assessed via comparisons with rainfall intensities.Recovery of Ks could be detected in the 0-6 cm depth after 12 years of secondary succession: P and SF5 held similar Ks values, but differed significantly (α = 0.05) from SF12 and SF100 which in turn were indistinguishable. Variability within the land cover classes was large but, due to sufficient replication in the study, Ks recovery could be detected nonetheless. Ks in the 6-12 cm depth did not show any differences between the land cover classes; only Ks of the uppermost soil layer was affected by land-use changes. Overland flow - as inferred from comparisons of Ks with rainfall intensities - is more likely on P and SF5 sites compared to SF12 and SF100 for the upper sample depth; however, generally low values at the 6-12 cm depth are likely to impede vertical percolation during high rainfall intensities regardless of land use.We conclude that Ks can recover from pasture use under secondary succession up to pre-pasture levels, but the process may take more than 8 years. In order to gain comprehensive understanding of Ks change with land use and its hydrological implications, more studies with detailed land-use histories and combined measurements of Ks, overland flow, precipitation and throughfall are essential. 相似文献
10.
Helmut Brandl 《Small-Scale Forestry》2011,10(2):135-147
This paper documents the development of the Accountancy Network in farm and small-scale forests in Baden-Württemberg, Germany,
from its inception until today. The main emphasis of the paper is to describe the experiences stemming from the establishment
of the network and running it for more than 30 years. The paper discusses the historical developments and their motivations.
It points out the positive and negative factors which influenced the development. Statistical and accounting issues are described
as examples of conflicts between scientific exactness and practicability and the respective solutions are presented. The reasons
for the network’s establishment, including its legal framework, how it was established and arising problems and difficulties
along with general information, results and its main benefits are the topics of the paper. The main idea of the network was
to obtain economic figures which were trustworthy and would meet the requirements of the users. Farmers were interested in
obtaining key data about their situation so they could manage their forests in a better way. The decision-makers in administrative
and political arenas were interested in better information on the economic situation of this type of private forestry. These
requirements necessitated statistical representativeness and the application of accounting principles similar to those of
industrial enterprises. This design has been successful; the financial results obtained have been judged as useful by all
groups who where interested in the figures. Therefore, the network will continue. 相似文献