Soil Structure,its Development and its Implications for Properties and Processes in Soils - a synopsis based on recent research in Germany

In a synoptic way the development of soil structure and its effects on processes in soils are treated, referring on more recent results of investigations in Germany. It is outlined that development of structure is an absolutely primary part of soil development which basically consists of the phenomena of loosening-versus-compaction and heterogenisation-versus-homogenisation. The process of aggregation is described together with its abiotic and biotic mechanisms and its consequences for the pore system and the processes which are influenced by it. A number of examples is given for the wide variety of mechanisms, chemisms and biologic processes which are influenced by soil structure and its change.     

Zur Provenienz Kiefernsamens

Ohne Zusammenfassung     

Ersch?pft sich die Forstwirtschft im Nutzen-Kosten-Dergleichen

Ohne Zusammenfassung     

Die taubenzecke,Argas reflexus,als plageerreger in menschlichen wohnungen

Ohne Zusammenfassung Mit 1 Abbildung.     

Keeping a cool head: honeybee thermoregulation

At high ambient temperatures, honeybees regulate head teriperature by evaporative cooling of regurgitated honeycrop contents. Thoracic temperature is secondarily stabilized as heat flows from thorax to head by means of passive conduction and physiological facilitation resulting from accelerated blood flow. The mechanism permits flight at the extraordinarily high ambient temperature of 46 degrees C without overheating the head and thorax despite prodigious amounts of heat produced as a by-product of flight metabolism. In contrast, at low ambient temperatures, thoracic rather than head temperature is regulated; no liquid is regurgitated, and the head is heated passively by conduction both in flight and while stationary.     

Luminescent colloidal silicon suspensions from porous silicon

A procedure for generating colloidal suspensions of Si that exhibit luminescence, attributed to quantum confinement effects, is described. Samples of n- or p-type Si that have been electrochemically etched to form porous Si can be ultrasonically dispersed into methylene chloride, acetonitrile, methanol, toluene, or water solvents, forming a suspension of fine Si particles that luminesce. Transmission electron microscopy analyses show that the Si particles have irregular shapes, with diameters ranging from many micrometers to nanometers. Luminescent, composite polystyrene/Si films can be made by the addition of polystyrene to a toluene suspension of the Si nanoparticles and casting of the resulting solution onto a glass slide.     

Carnivorous fungi from Cretaceous amber

Carnivorous fungi dating back to the age of the dinosaurs have been found fossilized in circa-100-million-year-old amber. The fossil fungi used hyphal rings as trapping devices and are preserved together with their prey, small nematodes. The excellent preservation in amber allowed comparison with extant groups: On the basis of the mode of ring formation and the dimorphic mode of life, the fossils cannot be assigned to any recent carnivorous fungus, providing evidence that different groups occupied this ecological niche in the Cretaceous and that trapping devices were developed independently multiple times in the course of Earth history.     

Alley coppice—a new system with ancient roots

Context

Current production from natural forests will not satisfy future world demand for timber and fuel wood, and new land management options are required.

Aims

We explore an innovative production system that combines the production of short rotation coppice in wide alleys with the production of high-value trees on narrow strips of land; it is an alternative form of alley cropping which we propose to call ‘alley coppice’. The aim is to describe this alley coppice system and to illustrate its potential for producing two diverse products, namely high-value timber and energy wood on the same land unit.

Methods

Based on a comprehensive literature review, we compare the advantages and disadvantages of the alley coppice system and contrast the features with well-known existing or past systems of biomass and wood production.

Results

We describe and discuss the basic aspects of alley coppice, its design and dynamics, the processes of competition and facilitation, issues of ecology, and areas that are open for future research.

Conclusion

Based on existing knowledge, a solid foundation for the implementation of alley coppice on suitable land is presented, and the high potential of this system could be shown.