Major problems of organic farming – experience transmission

As a very particular agricultural system organic farming encounters many problems. Some of these problems are common to several countries where organic farming is applied. On that ground it might be useful to compare condition and levels of organic farming in more countries, find its common problems and thanks to experience transmission try to eliminate some of these problems preventively. Mutual comparison of organic farming in the Czech Republic with organic farming in Austria and actual conditions assessment provide to determine main problems of organic farming in both countries. Within the framework of analysis of organic farming several general problems of organic farming in both countries were defined, e. g. lower yields and higher costs per production unit or legislative restrictions. At the same time for the Czech republic were defined major problems related to agricultural and socioekonomic differences (e. g. dual characteristics of farm size, high share of imported bioproduction) and for Austria (high prices of bioproducts, lower rate of conversion to organic farming) and proposed suitable solutions based on experience of partnership country. If the number of partnership countries with differentially developed organic farming was broaden and there was defined common problems and aims for organic farming in general it might be a very important step for simplification and acceleration of its development

Differences in the Morphological Characteristics of the Land Races of the Soft and Emmer Wheat in Relation to the Modern Varieties

For the organic farmers there is important question which varieties of wheat are right for organic farming in Less Favoured Areas. Modern varieties of wheat are bred in the conditions of conventional (high imput) farming. That is why the organic farmers asked about the suitability of land races of soft wheat (Triticum aestivum L.) or different species like emmer wheat grown in the past (Triticum dicoccum SCHUEBL). The paper results from the study of fourty land races, two intermediate and ten modern varieties of soft wheat in comparison to ten land races of emmer wheat at two locations in the Czech Republic. We evaluated tuft shape, length of plant, length and width of flag leaf, length and density of spike and awnedness. The modern varieties of soft wheat are characterised by a high level of uniformity. Their tuft shape is erect or semi-erect and length of plant is 60-70 cm, it does not rise the weed competitiveness. On the other hand, they have a medium or long flag leaf whose width is narrow or medium. Length of spike is medium or long. On the other hand, emmer wheat land races have the same tuft shape as forgoing modern varieties. Length of plant (89-119 cm) is the positive aspect of the weed competitiveness. Their flag leaf is narrow, but it is compesated by its length. The spike is shorter than the spike of modern varieties of soft wheat, but it is effectivelly compensated by an increased density. Intermediate wheat land races are characterised by looselly spreading tuft shape which puts the weeds down, but on the other hand, it favours the mildew because of the microclimate of soil. Its flag leaf is very short and narrow. Length of spike is medium and it is lax dense. The group of land races of soft wheat is characterised by a high diversity. The tuft shape is most frequently semi-erect. The length of plant varies from 60 to 120 cm, it usually ranges from 90 to 110 cm. Flag leaf is usually long or very long, but its width is very narrow or narrow. The spike is often long, but lax dense. Some of the evaluated varieties of landraces are proved to be suitable for organic farming from the point of view of the morphological characteristics

EFFICIENCY OF PRODUCTION ON ARABLE LAND IN ORGANIC AND CONVENTIONAL FARMING

One of the most evident difference between conventional and organic farming is yield height. Differences predominantly depend on the crop species and the major drop in yield when organic farming comes in the period of conversion, lower variability feature low-input species. Combination of factors defines overall yield distinction between conventionally and organically grown crops. Even if the organic farming reaches lower yields, differences in costs and prices of products have very strong positive effect on it´s efficiency, which could be even higher when compared to conventional farming

Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect

The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies

With increasing site quality asymmetric competition and mortality reduces Scots pine (Pinus sylvestris L.) stand structuring across Europe

Heterogeneity of structure can increase mechanical stability, stress resistance and resilience, biodiversity and many other functions and services of forest stands. That is why many silvicultural measures aim at enhancing structural diversity. However, the effectiveness and potential of structuring may depend on the site conditions. Here, we revealed how the stand structure is determined by site quality and results from site-dependent partitioning of growth and mortality among the trees. We based our study on 90 mature, even-aged, fully stocked monocultures of Scots pine (Pines sylvestris L.) sampled in 21 countries along a productivity gradient across Europe. A mini-simulation study further analyzed the site-dependency of the interplay between growth and mortality and the resulting stand structure. The overarching hypothesis was that the stand structure changes with site quality and results from the site-dependent asymmetry of competition and mortality.First, we show that Scots pine stands structure across Europe become more homogeneous with increasing site quality. The coefficient of variation and Gini coefficient of stem diameter and tree height continuously decreased, whereas Stand Density Index and stand basal area increased with site index.Second, we reveal a site-dependency of the growth distribution among the trees and the mortality. With increasing site index, the asymmetry of both competition and growth distribution increased and suggested, at first glance, an increase in stand heterogeneity. However, with increasing site index, mortality eliminates mainly small instead of all-sized trees, cancels the size variation and reduces the structural heterogeneity.Third, we modelled the site-dependent interplay between growth partitioning and mortality. By scenario runs for different site conditions, we can show how the site-dependent structure at the stand level emerges from the asymmetric competition and mortality at the tree level and how the interplay changes with increasing site quality across Europe.Our most interesting finding was that the growth partitioning became more asymmetric and structuring with increasing site quality, but that the mortality eliminated predominantly small trees, reduced their size variation and thus reversed the impact of site quality on the structure. Finally, the reverse effects of mode of growth partitioning and mortality on the stand structure resulted in the highest size variation on poor sites and decreased structural heterogeneity with increasing site quality. Since our results indicate where heterogeneous structures need silviculture interventions and where they emerge naturally, we conclude that these findings may improve system understanding and modelling and guide forest management aiming at structurally rich forests

Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect

The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies.Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effectpublishedVersio

Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect

The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies

Processo do projecto IMOA- International Museum of Astronomy en Deserto Atacama, Chile

As vertentes prática e teórica presentes nesta dissertação interligam-se através do processo de pesquisa e investigação em torno da problemática da construção de edifícios públicos implantados em territórios desabitados, paisagens naturais (tais como deserto e território montanhoso), ou qualquer área vazia despovoada no planeta - um objecto artificial num ambiente natural.A conclusão e os resultados apresentados sob a forma de texto e correspondente portefólio gráfico complementam-se. Os aspectos e as considerações necessários para a colocação do "Novo" edifício no "Antigo" ambiente natural pré-existente encontram-se divididos em três capítulos, de acordo com os aspectos visuais e geométricos.Percepção e impressão do "Novo" objecto encontram-se fortemente relacionadas com a direcção e distância da observação, as características da paisagem e os elementos naturais presentes, culminando numa desejável relação entre edifício e natureza.O estudo e a pesquisa teórica aplicam-se no exercício prático que serve como caso de estudo desta dissertação: o projecto do Museu Internacional de Astronomia no Chile. Os elementos e aspectos relevantes da implantação do edifício na paisagem são descritos na conclusão do projecto e nos respectivos capítulos.O principal objectivo do trabalho passa por reconhecer certos aspectos fundamentais e tecer considerações importantes sobre desenho e projecto de edifícios públicos em contexto natural, aspirando atingir uma coexistência harmoniosa de forma entre ambos. A qualidade visual destes projectos será, portanto, tão importante como questões de preservação ecológica e ambiental, que infelizmente são frequentemente ignoradas na arquitectura contemporânea.The theoretical and practical parts of my dissertation work are connected together in the processof research and investigation of the problematics of design for a public building; an artificial object,which is placed in the territory of vast uninhabited natural landscape, such as deserts and mountainpasses, or any abandoned empty areas on the planet Earth.The conclusion and results are presented in the form of text and corresponding image gallery alongsideit. The aspects and necessary considerations of placing a "New" building into "Old" pre-existentnatural environment are divided into three chapters, by their geometrical and visual characteristics.The perception and impression of such objects is strongly related to the direction and distance ofobservation, the characteristics of the present natural landmarks and elements and the desired relationship,which should exist between the building and the nature.The research work is followed by practical application of gained knowledge on the project of the InternationalMuseum of Astronomy in Atacama in Chile, which is the case study of the investigation. The relevant elements and aspects of implantation of such a building into natural landscape are described in the conclusion of the project and the related chapters of the text.The main goal of this work is to point out and describe the important considerations and aspects of the design process of placing public buildings in open natural landscapes, so that a harmonic formal relationship between the building and the nature can be achieved. The visual quality of such projects is just as important as the environmental- and eco- friendliness, and should not be overlooked. Sadly, that is a common case in modern architecture

L'exil de Jan Cep (contribution à l'histoire de la littérature tchèque moderne)

L écrivain tchèque Jan Cep (1902-1974), qui compta au nombre des médiateurs importants des rapports culturels franco-tchèques dans l entre-deux-guerres, fut, à la suite du Coup de Prague en 1948, contraint à quitter son pays. Ami et traducteur de Pourrat et de Bernanos, il choisit naturellement la France comme patrie d adoption. L exil parisien s avère pour Cep une rude épreuve existentielle. Conditions matérielles dures, déracinement linguistique, manque d écho favorable pour son oeuvre, tout cela fait que Cep vit en marge de la vie littéraire française. Il s engage d autant plus dans diverses structures de l émigration tchèque, notamment dans la rédaction tchécoslovaque de Radio Free Europe où il déploie son art de l essai dans des méditations imprégnées d humanisme chrétien. L essai autobiographique Ma soeur l angoisse que Cep écrivit directement en français dans les années 1960, représente la somme de sa vie et de sa penséeThe Czech writer Jan Cep (1902-1974), one of important mediators of French-Czech cultural relations between the two World Wars, was forced to emigrate after the Communist coup in 1948. As Cep was the friend and translator of Pourrat and Bernanos, he naturally chose France as his adoptive homeland. Nevertheless, exile in Paris turned into a harsh existential ordeal for Cep. Difficult material conditions, linguistic disunity, and the fact that his writing was not accepted by a new audience made Cep an outsider in a French literary life. This status led to his increased involvement in the Czech émigré community, especially work on the Czechoslovak editorial staff of Radio Free Europe, where he developed his essay style in meditations infused with Christian humanism. The autobiographical essay My Sister Anxiety, written in French in the 1960s, repesents a summary of Cep s life and ideasPARIS-EST-Université (770839901) / SudocPARIS12-Bib. électronique (940280011) / SudocSudocFranceF