En Tunisie, comme dans plusieurs pays méditerranéens, la céréaliculture est une activité très consommatrice de pesticides, (63% de la consommation totale de l'agriculture tunisienne). Par conséquent, il est nécessaire d'étudier le devenir des pesticides appliqués afin de réduire les quantités perdues dans l'environnement tout en maintenant un niveau acceptable de l'efficacité des traitements. Plusieurs études ont montré qu'après leur éjection par la buse, les gouttes sont plus ou moins soumises aux phénomènes de dérive et de perte au sol pendant l'application. La partie principale de ce travail est basée sur le développement et la validation d'un modèle capable de calculer les dépôts, la volatilisation, (évaporation et pertes vers l'air) sous le vent, en grandes cultures. Le modèle DriftL a été alors construit sous le logiciel SciLab, version 5.03. Il a été calé à partir de mesures réalisées sous des conditions contrôlées en soufflerie et a bénéficié d'une validation expérimentale. Une deuxième partie a étudié expérimentalement les pertes directes au sol et la rétention sur les plantes en conditions de laboratoire. Comme le travail mené en soufflerie, elle a permis de mettre en évidence une relation entre la granulométrie de la pulvérisation, la hauteur des buses, les variables microclimatiques et les dépôts mesurés dans les compartiments air, sol et plante. Pour effectuer les mesures, une démarche expérimentale a été mise en place afin de choisir la méthode de travail. Après de nombreux tests, un collecteur a été sélectionné pour chaque compartiment. Une rampe mobile a été également fabriquée pour jouer le rôle du pulvérisateur dans les conditions de laboratoire. Les mesures effectuées au champ ont permis de valider des calculs de DriftL et des résultats obtenus au laboratoire / In Tunisia, as in many Mediterranean countries, cereal is a very very pesticides intensive crop (63% of overall Tunisian agriculture consumption). Consequently, it is necessary to study the fate of applied pesticides to reduce the losses to the environment and maintain an acceptable effectiveness of treatments. Several studies have shown that after their ejection from the nozzle, drops are subject to drift and ground loss during application.The main part of this work is based on the development and validation of a model to calculate drift in field crops. Thus was developed our model, DriftL, under Scilab software, version 5.03. It has been stalled from controlled conditions measurements in a wind tunnel and received experimental validation. A second part studied experimentally the direct soil losses and plants retention under laboratory conditions. As well as the wind tunnel results, it has showed a relationship between the size of the drops VMD, the microclimatic variables and deposits in the concerned compartments.To measure deposits, an experimental approach has been established in order to choose the work method. After numerous tests, one collector was selected for each compartment. A device was also built to replace the sprayer in laboratory conditions. The field measurements were used to discuss DriftL calculations and laboratory results.

The aim of the paper: to investigate the effect of microclimatic factors on the process of ammonia emission from manure, and evaluate possibilities to reduce ammonia emission from cowsheds by controlling these factors. The completed analysis of microclimatic factors in various naturally ventilated cowsheds revealed patterns of variation in ammonia concentration depending on air temperature in the barn. While analysing the process of ammonia evaporation from the manure, the effect of interacting environmental factors on the intensity of evaporation was evaluated. The effect of temperature, ventilation intensity and drying of manure surface on the intensity of ammonia evaporation process from manure was determined and proved. Theoretical and experimental presumptions were made for the investigation of the effect of the crust formation at the manure surface on ammonia diffusion process. Based on the obtained results, ammonia emission from naturally ventilated cowsheds with various engineering solutions can be predicted, and equipment reducing the ammonia emission from them can be installed. / Darbo tikslas ˗ Ištirti mikroklimato veiksnių įtaką amoniako emisijos procesui iš mėšlo ir įvertinti galimybes juos valdant sumažinti amoniako emisiją iš karvidžių. Ištyrus mikroklimato veiksnius įvairiose natūraliai vėdinamose karvidėse, nustatyti amoniako koncentracijos kaitos dėsningumai priklausomai nuo oro temperatūros tvarte. Analizuojant amoniako garavimo iš mėšlo procesą, įvertinta tarpusavyje sąveikaujančių aplinkos veiksnių komplekso įtaka garavimo intensyvumui. Nustatyta ir įrodyta temperatūros, vėdinimo intensyvumo ir mėšlo paviršiaus džiūvimo įtaka amoniako garavimo iš mėšlo proceso intensyvumui. Sukurtos teorinės ir eksperimentinės prielaidos tirti mėšlo paviršiuje besiformuojančios plutos įtaką amoniako difuzijos procesui. Pagal gautus rezultatus galima prognozuoti amoniako emisiją iš natūraliai vėdinamų karvidžių su įvairiais inžineriniais sprendimais ir diegti priemones mažinančias amoniako emisiją iš jų.

The objective of this thesis is to characterize the Labská rokle creek icefall in terms of its morphology and types of ice structures. It describes the icefall's development during the winter season and analyses the impact of meteorological factors. The data about the icefall's volume were collected via sequential photographing and 3D scanner measuring during the winter seasons 2014/15 and 2015/16. The collected data were compared with the data from temperature sensors situated below the icefall and in its close proximity and with the data from the meteorological station in Labská bouda hut. The given icefall showed a very fast growth in the first phase of its development. This phase was followed by a typically stable phase of small fluctuations and subtle reactions to surrounding stimuli. In the third phase, a rapid decline in volume occurred as a result of either episodic events, such as when a larger piece of ice came loose, or progressive thawing. Regarding the factors, it was confirmed that temperature had the biggest impact on the volume of the icefall. A very high correlation was also found to be between the icefall's volume and the height of snow. A bigger snow height apparently puts off the stable phase and allows a greater accumulation of ice. The impact of global radiation and sunlight...