The cultivation of fast growing tree species on arable land is deemed to be one of the most promising alternatives amongst the approaches to the cultivation of renewable resources currently available. As the site factors influencing the growth of poplar and willow have not yet been sufficiently identified and quantified, it is not possible to provide reliable national yield expectations as a function of the prevailing soil and climate conditions at a particular site on the basis of the data currently available. The main objective of this study, therefore, was to develop a supraregional site-based yield model for the assessment of yield expectations for poplar and willow grown on arable land over short rotations. In order to achieve this goal, a total of 38 research sites were established across as many regions of Germany as possible. The clones selected for the experiment were the poplar clones Max 1, Hybride 275 (H 275) and AF 2, and the willow clones Inger and Tordis. Each site was also characterised, on the basis of climate and soil data. From the site parameters recorded, variables were defined for modelling purposes. The climate variables comprised temperature (T), precipitation (N) and aridity index (TI) derived from total or average values from selected periods during the year and during the vegetation period. Within the variables the months were indexed as numbers (January = 1), periods were separated by comma. Parameters of the German soil appraisal such as the condition grade (ZS), the soil quality index value (BZ) and the arable land quality index value (AZ) were used as soil variables. The selected texture parameters were the proportions of sand (S[%]), silt (U[%]) and clay (T[%]). Variables of the pore space parameters were the available field moisture capacity (nFK), the air capacity (LK) and the dry bulk density (TRD). Both the texture and the pore space variables referred to a soil depth of 0 to 60 cm. To increase the precision of the results, site clusters were derived, differentiated by main soil type, and the variables were aggregated. The dGZ, measured in odt ha-1 a-1,at the end of the first three-year rotation was chosen as the dependent variable. The main results of the study are outlined in the following: Negative correlations between dGZ and temperatures in the vegetation period, especially in the months July to September, were observed on the sandy and loamy soils. Precipitation variables always had a positive effect on the growth of poplar and willow across all clones and site clusters. Taking into consideration all experimental sites, precipitation in the period from May to July was most important. The parameters of the German soil appraisal revealed a moderate correlation with growth for all sites. From the appraisal of all sites and of the individual site clusters it became apparent that U[%] represents the most important texture variable for poplar and willow growth. Considered for all sites simultaneously, the nFK had the greatest significance for growth across all of the parameters examined. The site-based yield models were all univariate and often comprised aggregated variables. Under consideration of all sites, the model predictors for Max 1, Inger and Tordis were (nFK * TI5.7) and (nFK * N5.7) for AF 2. Each model was calculated with the inverse or sigmoid approach and revealed an R²korr between 0.45 and 0.64 with a RMSE of an average of 2.0 odt ha-1 a-1. The division into site clusters improved the accuracy of the models considerably. In the sandy site cluster, the models exhibited an R²korr of 0.77 to 0.97 and an RMSE of 0.95 to 1.36 odt ha-1 a-1. These comprised (U[%]* N6.7) for Max 1 and F 2, (S[%]/ TI6.7) for H 275 and (S[%]* T7.8) for Inger and Tordis. For the silty site cluster, significant models could only be determined for the clones Max 1 and Tordis. The model predictor for Max 1 was (BZ * TI4.5) and for Tordis solely (BZ). The calculated R²korr values were 0.84 and 0.95 with a corresponding RMSE of 0.22 and 0.62 odt ha-1 a-1, respectively. For the loamy soils the models for Max 1 and Inger comprised the variable nFK, for AF 2 the variables (nFK * N5.6). R²korr varied between 0.86 and 0.98 with RMSE between 0.56 and 1.21 odt ha-1 a-1.

This thesis concerns Precision Agriculture (PA) technology which involves methods developed to optimise grain yield by examining data quality and modelling protein/yield relationship of wheat and sorghum fields in central and southern Queensland. An important part of developing strategies to optimisise grain yield is the understanding of PA technology. This covers major aspects of PA which includes all the components of Site- Specific Crop Management System (SSCM). These components are 1. Spatial referencing, 2. Crop, soil and climate monitoring, 3. Attribute mapping, 4. Decision suppport systems and 5. Differential action. Understanding how all five components fit into PA significantly aids the development of data analysis methods. The development of PA is dependent on the collection, analysis and interpretation of information. A preliminary data analysis step is described which covers both non-spatial and spatial data analysis methods. The non-spatial analysis involves plotting methods (maps, histograms), standard distribution and statistical summary (mean, standard deviation). The spatial analysis covers both undirected and directional variogram analyses. In addition to the data analysis, a theoretical investigation into GPS error is given. GPS plays a major role in the development of PA. A number of sources of errors affect the GPS and therefore effect the positioning measurements. Therefore, an understanding of the distribution of the errors and how they are related to each other over time is needed to complement the understanding of the nature of the data. Understanding the error distribution and the data give useful insights for model assumptions in regard to position measurement errors. A review of filtering methods is given and new methods are developed, namely, strip analysis and a double harvesting algoritm. These methods are designed specifically for controlled traffic and normal traffic respectively but can be applied to all kinds of yield monitoring data. The data resulting from the strip analysis and double harvesting algorithm are used in investigating the relationship between on-the-go yield and protein. The strategy is to use protein and yield in determining decisions with respect to nitrogen managements. The agronomic assumption is that protein and yield have a significant relationship based on plot trials. We investigate whether there is any significant relationship between protein and yield at the local level to warrent this kind of assumption. Understanding PA technology and being aware of the sources of errors that exist in data collection and data analysis are all very important in the steps of developing management decision strategies.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The mapping of grain yield is the main tool for analysis of the results of the techniques of precision agriculture used. In this sense, the aim of this study was to describe the equipment and clarify the current state of the art mapping yield (Chapter I), to analyze the occurrence of similarity between maps over time using different cultures (Chapter II), and finally, determine the influence that soil properties exert on crop yields (Chapter III). In Chapter I deal with the basic equipment that composes a set of monitoring harvest, giving emphasis on yield sensors on the market, the sequence shows the possibilities of using yield maps for management areas. For analysis of yield stability (Chapter II), there were four areas with a history of monitoring four crops of soybean, corn, wheat and oats. The areas were divided by a regular grid (20 x 20 m) for each raster is assigned the value of average yield of the points that were inside. Data were normalized to enable the temporal analysis. The correlation between soil properties and productivity (Chapter III) was evaluated in an area of 88 acres using the Spearman correlation. The soil samples were taken manually auger at a depth from 0 to 0.1 m, over a regular grid (50 x 50 m). The yield values of these points were determined by averaging the sample points using different radius in three cultures. The results demonstrated the presence of yield stability, especially in areas with large variation in yield in one year. The methodology should be used with caution, especially in places where there is a tendency to homogeneity in yield. The radius sample used to determine the value of yield point has a direct influence on the values of the correlations. Increasing the radius to the sample value of 30 meters provided significant gradual increase in the values of correlations. The phosphorus was the nutrient that showed high positive correlation with yield, despite being above the levels described for the critical state. / O mapeamento da produtividade de grãos constitui a principal ferramenta de análise dos resultados das técnicas de agricultura de precisão utilizadas. Neste sentido o objetivo do estudo foi descrever os equipamentos e esclarecer o estado atual da arte de mapeamento da produtividade (capitulo I), analisar a ocorrência de similaridade entre mapas ao longo do tempo utilizando diferentes culturas (capitulo II) e, por fim, determinar a influência que os atributos do solo exercem na produtividade das culturas (capitulo III). No capítulo I são descritos os equipamentos básicos que compõe um conjunto de monitoramento de colheita, dando ênfase para os sensores de produtividade presentes no mercado, na sequencia são apresentadas as possibilidades de utilização dos mapas de produtividade para gerenciamento das áreas. Para análise da estabilidade produtiva (capitulo II), foram utilizadas quatro áreas com um histórico de monitoramento de quatro safras das culturas da soja, milho, trigo e aveia. As áreas foram divididas por uma malha quadricular (20 x 20 m), para cada quadricula se atribuiu o valor de produtividade médio dos pontos que se encontravam no seu interior. Os dados foram normalizados para possibilitar a análise temporal. A correlação entre atributos do solo e a produtividade (capitulo III) foi avaliada em uma área de 36 hectares utilizando a correlação de Spearman. As amostragens de solo foram realizadas manualmente com trado calador na profundidade de 0 - 0,1 m, através de uma malha regular (50 x 50 m). Os valores de produtividade destes pontos foram determinados através da média dos pontos utilizando diferentes raios amostrais em três culturas. Os resultados demonstraram a presença de estabilidade produtiva, sobretudo em áreas que apresentam grande oscilação na produtividade em um mesmo ano. A metodologia deve ser utilizada com cautela, principalmente em locais onde há uma tendência à homogeneidade na produtividade. O raio amostral utilizado para determinar o valor de produtividade de um ponto tem influencias diretas sobre os valores das correlações. O aumento do raio amostral até o valor de 30 metros proporcionou aumentos graduais significativos nos valores das correlações. O fósforo foi o nutriente que apresentou maiores correlações positivas com a produtividade, mesmo estando acima dos teores críticos descritos para o estado.

La convection de Rayleigh-Bénard est étudiée expérimentalement dans une cellule circulaire. Des fluides à seuil modèles (gels aqueux de Carbopol) sont mis en œuvre. Leurs comportements rhéologiques et leurs perméabilités en relation avec leurs microstructures ont été finement caractérisés. Dans toute la thèse, les expériences ont été menées sans glissement à la paroi. L'influence du seuil d'écoulement et de la distance entre plaques chaudes et froides sur les transferts thermiques a été approfondie. Trois mécanismes sont discutés pour expliquer le déclenchement de la convection: i) les propriétés visco-élastiques au-dessous du seuil, ii) le fluage au-dessous du seuil, iii) une approche d'un milieu poreux pour les gels de Carbopol considérés comme une suspension de micro-gels. On montre que le nombre de seuil Y, représentant le rapport entre la contrainte du seuil et la contrainte de la poussée d'Archimède est un paramètre important gouvernant l'apparition de l'instabilité. Les valeurs critiques de Y^(-1) sont déterminées entre 60 et 90. La visualisation à l'aide des cristaux liquides thermo-chromiques a permis une vue globale de la cinématique. Les structures observées dans les différents états thermiques montrent l'évolution de la convection. Une analyse qualitative du champ de température est également présentée. Enfin, la simulation numérique dans une cellule carré avec un modèle d'Herschel-Bulkley régularisé dans la gamme des nombres sans dimension utilisée dans les expérience a permis de mettre en évidence les paramètres critiques et la morphologie des champs thermiques et cinématique. Les ordres de grandeurs du nombre de seuil critique prédit se comparent raisonnablement avec les valeurs expérimentales. / In this thesis, three main mechanisms proposed in a recent paper (Darbouli et al., Physics of fluids, 25(2) 2013) have been discussed to explain the onset of Rayleigh Bénard Convection in a yield fluid (Carbopol gels): i) the elasto-visco-plasticity behavior of the material below the yield stress, ii) a viscosity at low values of shear rates by creep measurements below the yield stress, iii) a microscopic viewpoint considering the fluid as a porous two phases system. No-slip conditions have been achieved for all the experiments. The results with different Carbopol gels have proved the importance of Y, the yield number which presents the report of the yield stress and the buoyancy effect, as the governing parameter. The critical value of Y^(-1) with no-slip condition has been found between 60 and 90. A visualization measurement with the utilization of thermochromics liquid crystals presents a global view from above. Different structures have been observed in different states of thermal conditions, which describe the evolution of the convection. For several cases the color of the liquid crystals can indicate the temperature field in the whole experiment cell. Numerical simulations with a Herschel-Bulkley model have also been discussed in this thesis. The dimensionless parameters are defined approaching the values obtained in the experiments, so that we can compare the numerical results with some of experimental ones.

Diploma work was performed on a total of six lots in Vysočina County, where he measured the effect of the separation, the effect of weather and temperatures, and comparing technologies casing Rock removal of soil and techniques of planting and harvesting on quality, yield potato starch content and yield and mechanical damage of potato tubers. The aim of the thesis was to evaluate the effect of casing Rock removal of the content and starch yield and mechanical damage of potato tubers. Were evaluated three varieties of potatoes destined for processing into starch. Ornella varieties, Susan and Eurostarch. All three varieties were investigated on land záhonovým odkameněním without Rock removal. In the reporting year for all three varieties to odkameněných land has been greater yield of starch and up 2% and damage decreased by 20%. In parallel, it was found that the difference in tuber yield per hectare of the land is záhonovým odkameněním and land without casing Rock removal were influenced by variety.

The aim of this thesis was to determine the effect of row spacing on sorghum yields and dry matter. The trial was established on 29 May 2015 on land belonging to the Agricultural Cooperative Milevsko, which is situated in the corn-growing area. The trial compared four varieties of sorghum, namely Aristos, Goliath, KWS Freya and KWS Sole. The varieties were sown in different row spacings, namely 75 cm, 60 cm, 45 cm a 30 cm. The samples taken on three dates were analysed for dry matter content. Each variety showed a gradual increase in the dry matter content. During the harvest on 5 October 2015 the varieties KWS Freya and KWS Sole reached an optimal value of the dry matter when planted in all spacings. All varieties produced the highest average yield of green matter when planted in rows spaced 60 cm apart. The variety Aristos produced the highest average yield of green matter. The KWS Sole variety reached the lowest average yield of green matter when planted in rows 76 cm apart. All varieties with 60 cm row spacings, except for KWS Sole, produced the highest average yield of dry matter. The highest average yield of dry matter was reached by Aristos and the lowest by KWS Sole. The results of the one-year trial did not prove a direct connection of the effect of row spacing on dry matter. The effect of row spacing on green and dry matter yield was proved. The optimum row spacing seems to be 60 cm.

The work deals with the influence of the Milk thistle (used substance Silymarin) on the carcass yield of hybrid combinations rabbits Hyla. Hybrid combination Hyla was purposefully bred for meat performance, showing excellent results in breeding. Rabbits behave primarily on meat, because nutritional properties correspond to the current requirements of rational nutrition. Therefore, it is appropriate to increase the carcass yield. The average slaughter yield is indicated from 40 to 53% according to the breed. It was found that the addition of milk thistle in the form of a powder in the complete feedingstuff at a concentration of 0.2% increased the carcass yield, relative to the control group (which was fed only KKS), on average by 0.4%. The group with the addition of 1% showed an average value of 1.2% higher than the group control. The average slaughter yield of all the groups ranged from 54,68 into 63,02%. In both farms also decreased the incidence of diarrheal disease. Silymarin has a favorable effect on the operation and growth of the liver. In the group with the addition of 0.2% increased the average liver weight of 8.1 g, in the group with a concentration of 1% weight on average picked up about 10g. The average weight of the liver varied from 111,19 to 121,20 g. The control group in the case of carcass yield and liver weight showed better results than the authors of their articles.

Fatores ambientais são determinantes nos processos fisiológicos das plantas de milho, no acúmulo de matéria seca e no rendimento da cultura. O objetivo desse trabalho foi avaliar as interações entre as variáveis ambientais com o crescimento, desenvolvimento e produtividade do milho (Zea mays L.) em quatro épocas de semeaduras, com destaque para a eficiência no uso da radiação e da água. Para tanto, um experimento de campo foi conduzido na região de Arapiraca, (09º48 55,1 S, 36º36 22,8 W e altitude de 236 m), Alagoas Brasil. O experimento foi conduzido, durante a estação chuvosa, de maio a outubro de 2008 com quatro épocas de semeadura. A primeira época de semeadura (T1) ocoreu no dia 06 de maio, a segunda (T2) no dia 19 de maio, a terceira no dia 10 de junho e a quarta no dia 30 de junho de 2008, utilizando a variedade Al Bandeirante. Os elementos meteorológicos foram medidos através de sensores, instalados na estação meteorológica localizada na área contígua ao experimento e os dados de umidade do solo foram capturados através de sensores, utilizando a reflectometria no domínio do tempo (TDR), coletadas durante a estação de crescimento da cultura. A evapotranspiração de referência (ETo), a evapotranspiração da cultura (ETc) e a evapotranspiração real (ETr) foram estimadas pela metodologia definida no Boletim FAO-56. A análise das interações agrometeorológicas do milho mostraram que a taxa de crescimento da cultura (TCC) em g m-2 dia-1, o índice de área foliar (IAF) no estádio fenológico de grãos farináceos (R4) e a produtividade de grãos foram menores na última época de semeadura (T4), quando comparadas às demais épocas (T1, T2 e T3). Já os valores da área foliar específica (AFE) não apresentaram diferenças entre si, para as quatro épocas de semeadura. A evapotranspiração real (ETr) variou de 356 mm, na primeira época de semeadura (T1) a 229,6 mm na última época (T4), enquanto a eficiência no uso da água (EUA) esteve no intervalo de 4,28 kg m-3 na terceira época (T3) a 3,76 kg m-3 de matéria seca, na quarta época de semeadura (T4). Na primeira época de semeadura (T1), verificou-se uma eficiência no uso da radiação (EUR) de 4,61 g de massa seca por MJ m-2 de radiação fotossinteticamente ativa absorvida (RFAabs), enquanto a quarta época (T4), contabilizou 2,98 g de massa seca por MJ m-2 de RFAabs, sendo 35,4% menor que T1. Diante das observações conclui-se que a menor produtividade foi verificada no tratamento T4, decorrente das modificações morfofisiológicas, ocorridas nas plantas de milho, causadas pelas alterações ambientais.

Introdução: O complexo anatômico-funcional localizado na junção esôfagogástrica é uma barreira ao refluxo gastresofágico. A pressão e o volume intragástricos necessário para vencer essa barreira são denominados Pressão de Vazão Gástrica e Volume de Vazão Gástrico e são utilizados em modelos animais para medir a sua competência, entretanto, a sua validação ainda não foi determinada. Objetivos: Desenvolver um modelo experimental suíno e validar a pressão e o volume intragástricos para estudo da barreira antirrefluxo. Métodos: Suínos da raça Large White com 8 semanas de vida, do sexo feminino foram utilizados neste experimento. Após a anestesia dos animais, foi realizada a manometria esofágica e um cateter de pHmetria posicionado 5 cm acima do esfíncter esofágico inferior. Uma sonda Foley de três vias foi introduzida no estômago através de gastrostomia e o duodeno obliterado através de um laço com gaze úmida. HCL (0,1N) foi infundido lentamente no estômago e medidos a pressão e o volume intragástricos, em tempo real em sistema digital. A pressão e o volume intragástricos no momento da queda abrupta do pH esofágico (pH< 3) foram definidas como Pressão de Vazão Gástrica (PVG) e Volume de Vazão Gástrico (VVG). Após o experimento, a sonda Foley foi retirada, o duodeno liberado e a gastrostomia ocluida com pontos cirúrgicos. Os animais foram mantidos em local apropriado até a repetição dos experimentos sete dias após. Resultados: Dez animais (peso médio = 20 Kg) foram estudados. Os valores médios (± DP) nos dias 0 e 7 foram, respectivamente: PVG 7,66 ± 3,02 versus 7,07 ± 3,54 (p =0,510 teste t de student e 0,557 para o teste exato de Wilcoxon) e VVG 636,70 ± 216.74 versus 608,30 ± 276,66; (p =0,771 teste t de Student e 0,846 para teste de Wilcoxon) não apresentaram diferença estatística significativa. Entretanto, quando aplicado o Coeficiente de Correlação de Concordância a reprodutibilidade foi significativa apenas para a PVG (CCC de 0,648), mas não para a VVG (CCC de 0,27). Conclusão: O modelo animal desenvolvido identifica reprodutibilidade para a PVG, mas não para a VVG. A PVG pode ser utilizada com confiança para o estudo da barreira anti-refluxo. / Introduction: The anatomic functional complex situated at the esophago-gastric junction is a barrier to gastroesophageal reflux. The intragastric pressure and volume necessary to overcome this barrier is called Gastric Yield Pressure and Gastric Yield Volume and used in animal models to measure the anti-reflux competence. However, its validation has not been determined. Objectives: Develop an experimental pig model and validate the intragastric pressure and volume to study the anti-reflux barrier. Methods: Large White pigs two month-old females were used in this experiment. After anesthesia esophageal manometry and a pH sensor placed 05 cm above the lower esophageal sphincter. A threeway Foley catheter was introduced into the stomach through a gastrostomy and duodenum tied with a wet gauze. The Foley probe allowed simultaneous HCl (0.1 N) infusion into the stomach and real time measurement of the intragastric pressure and volume on a digital system system. The intragastric pressure and volume simultaneous to a sudden fall in esophageal pH (pH <3) were defined as the Gastric Yield Pressure (GYP) and the Gastric Yield Volume (GYV). After the experiment, the Foley was removed, the duodenum untied and gastrostomy occluded with surgical stitches. The animals were kept in an appropriate room and the experiment repeated after seven days. Results: Ten animals (mean weight = 20 kg) were studied. The mean values (± SD) on days 0 and 7 were, respectively: GYP 7.66 ± 3.02 and 7.07 ± 3.54 (p = 0,510 student t test and 0.557 for Wilcoxon’s exact test) and GYV 636.70 ± 216.74 and 608.30 ± 276.66, (p =0,771 student t test and 0.846 for Wilcoxon) had no significant statistic difference. However, when the concordance correlation coefficient was applied reproducibility was found only for GYP (CCC = 0,648) but not for GYV (CCC = 0.27). Conclusion: The developed animal model disclosed reproducibility for GYP but not for GYV. GYP may be used with confidence to study the anti-reflux barrier.

This thesis focus on a yield curve modelling. It estimates unobserved "global" yield curve factors which drives changes in individual real yield curves. Yield curves of USD, GBP, JPY and EUR are considered and global factors are able to explain substantial part of their variances. The method is built on the Nelson-Siegel model which is implemented in a state-space form to be able to extract the unobserved yield factors. The estimated global yield factors are further used for explaining the evolution of the Czech yield curve. Their impact to the Czech yield curve is estimated in a time-varying regression which results show that the impact of the global factors is stronger during the years of the interventions of the Czech National Bank and thus suggests that the interventions help to transmit the global low interest rates to the Czech economy.