In this study, I attempted to evaluate the impact of two forest disturbances on the soil temperature and humidity in spruce forest. The spruce forests were attacked by bark beetle in the Březník area 17 years ago. Two types of management were applied after the bark beetle attack. The first approach was clear cutting and removing dead trees. The second approach was non-interventional and this zone was left to natural succession. This study compares differences in daily temperature amplitude and volumetric soil humidity between both types of management. I tried to evaluate whether the soil temperature and humidity conditions are explained more by influence of the management or by vegetation cover. Results showed significant difference in daily temperature amplitudes. Temperature amplitudes are about 49 % higher in clear cut areas than in areas with natural succession. Differences are insignificant in soil humidity conditions. The influence of the vegetation on soil temperature and humidity is insignificant. I, too, compared soil temperature and humidity from Březník areas (17 years after disturbance) and Prameny Vltavy areas where the spruce forest decayed recently.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Continuous use of fertilizer in high concentrations has been raising concerns on environmental pollution associated with the modernization and specialization of agricultural production and livestock systems. With this, consumers are understandably concerned and demand that production in agricultural systems be combined with sustainability and production efficiency. The purpose of this study was to evaluate the agronomic performance of maize inoculated with Azospirillum brasilense and different doses of nitrogen in crop-livestock integration system managed with different post-grazing forage masses and interference of abiotic factors on the vegetative development of the crop. Three studies were conducted, one in the field and two in a protected environment. The field study was conducted in the municipality of Mata, in a Rhodic Paleudalf, in the experimental design of randomized blocks with sub-divided plots, three repetitions, in factorial scheme of 5x2x5 (post-grazing forage mass, Azospirillum brasilense and doses of nitrogen). The heights of the post-grazing forage mass were 0.10m, 0.20m, 0.30m, conventional grazing and without grazing, with doses of nitrogen that varied between 0.75, 150, 225 and 300 kg ha-1, with and without inoculation. Studies began in the year 2014, with the management of the forage in two winters and two years of assessing the crops at field level in the agricultural years of 2014/2015 and 2015/2016. The other two studies in protected environment were conducted at the Federal University of Santa Maria, from November 2015 to April 2016. The treatments in the first study were maize inoculated or not, in nutrient solution with five variations of pH (4.5; 5.0; 5.5; 6.0 and 6.5), in bifatorial arrangement with three repetitions. In the second experiment, different levels of soil humidity with and without inoculation were evaluated, with four repetitions in soil moisture field capacity of 25%, 50%, 75% and 100%. Both studies used the hybrid DEKALP 240 and inoculant "AzoTotal" (liquid). The field study was evaluated the agronomic traits and yield components of maize, from the beginning to the end of the crop cycle. In the studies conducted in a protected environment, evaluations of the shoot and root system occurred until the phenological stage V4. In the field study, the analysis of inoculation observed an increase of 13% for use of Azospirillum brasilense in the treatment of maize seed for the 2014/2015 harvest. Azospirillum brasilense provided an increase in productive gain of 4.5% in regards to its absence. It was possible to observe, therefore, that plants with the presence of the bacteria improve their root system in soil with hydric stress. When the root volume increased, part of the shoot of the crop decreased. The use of diazotrophic bacteria contributed to the increment of the photosynthetic pigments in the maize leaves when in water deficit. Root and shoot development of maize were affected by the variation of pH of solution. Given these results, the presence of Azospirillum brasilense favors plant growth, increases root volume and improves grain productivity, especially in years of cultivation with less precipitation during the stage of plant growth. The presence of Azospirillum brasilense extends the magnitude of pH with possibility of cultivation for maize. / O uso contínuo de fertilizantes em altas concentrações vem alavancando as preocupações relacionadas com a poluição ambiental associados com a modernização e especialização dos sistemas de produção agrícola e de pecuária. Com isso, consumidores estão preocupados, e exigem que a produção nos sistemas agropecuários seja aliada a sustentabilidade e a eficiência produtiva. O objetivo do presente trabalho foi avaliar o desempenho agronômico da cultura do milho inoculado com Azospirillum brasilense e diferentes doses de nitrogênio em sistema de integração lavoura-pecuária manejado com diferentes massas de forragem pós-pastejo e interferências de fatores abióticos no desenvolvimento vegetativo da cultura. Três estudos foram conduzidos, sendo um a campo e dois em ambiente protegido. O estudo a campo foi conduzido no município de Mata, em um Argissolo Vermelho Distrófico arênico, no delineamento experimental de blocos ao acaso com parcelas subdivididas, três repetições, em esquema fatorial 5x2x5 (massa de forragem pós-pastejo, Azospirillum brasilense e doses de nitrogênio. As alturas de massa de forragem pós-pastejo compreenderam a 0,10m, 0,20m, 0,30m, pastejo convencional e sem pastejo, com doses de nitrogênio que variaram de 0, 75, 150, 225 e 300 kg ha-1, com e sem inoculação. Os estudos iniciaram no ano de 2014, com o manejo das forragens em dois invernos e dois anos de avaliação da cultura do milho em nível de campo nos anos agrícolas 2014/2015 e de 2015/2016. Os outros dois estudos em ambiente protegido foram conduzidos na Universidade Federal de Santa Maria, no perido de novembro de 2015 a abril de 2016. Os tratamentos no primeiro estudo foram milho inoculado ou não, em solução nutritiva com cinco variações de pH s (4,5; 5,0; 5,5; 6,0 e 6,5), em arranjo bifatorial com três repetições. No segundo experimento avaliou-se diferentes níveis de umidade do solo com e sem inoculação, com quatro repetições nas umidades de capacidade de campo 25%, 50%, 75% e 100%. Para ambos os estudos se usou o hibrido DEKALP 240 e o inoculante AzoTotal (líquido). No estudo de campo foi avaliado características agronômicas e os componentes de produtividade da cultura do milho, do início ao fim do ciclo da cultura. Nos estudos em ambiente protegido as avaliações de parte aérea, e sistema radicular ocorreram até estádio fenológico V4. No estudo de campo, o desdobramento do fator inoculação foi constatado um incremento de 13% para utilização do Azospirillum brasilense no tratamento de sementes de milho para a safra 2014/15. O Azospirillum brasilense proporcionou um incremento no ganho produtivo de 4,5% em relação a sua ausência. Plantas com a presença da bactéria, melhoram seu sistema radicular em solo com estresse hídrico. Quando aumentou o volume de raiz, reduziu a parte aérea da cultura. A utilização das bactérias diazotróficas contribuiu para incremento dos pigmentos fotossintéticos nas folhas do milho quando em déficit hídrico. O desenvolvimento radicular e a parte aérea da cultura do milho, foram afetados pela variação do pH de solução. Diante desses resultados, a presença do Azospirillum brasilense favorece o crescimento das plantas, aumenta o volume de raiz e incrementa a produtividade de grãos, principalmente em anos de cultivo com menor precipitação pluviométrica durante a fase de crescimento das plantas. A presença do Azospirillum brasilense amplia a magnitude de pH s com possibilidade de cultivo para milho.

Orientador: Elnatan Chagas Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T03:41:59Z (GMT). No. of bitstreams: 1 Duarte_LuisFernandoCaparroz_M.pdf: 22217268 bytes, checksum: 70f7c5dbf0e7a70f46654592aa364159 (MD5) Previous issue date: 2010 / Resumo: A preocupação com o futuro dos recursos hídricos e o valor agregado dos produtos da agricultura de precisão leva os produtores agrícolas a procurarem formas mais inteligentes e precisas do manejo da água. Neste trabalho apresenta-se uma proposta de um sistema automatizado georreferenciado de irrigação localizada baseado em leitura de sensor de umidade do solo, que visa baixo custo e é independente de uma rede de comunicações atuante em tempo integral ou de uma central de processamento. Neste trabalho foi desenvolvido um Módulo de Irrigação Localizada Inteligente, que atua de acordo com o processamento das informações obtidas pelo sensor de umidade do solo. Também foram desenvolvidos um Módulo Programador responsável pela entrada dos dados e programação dos módulos de irrigação e um Módulo Acionador para Bombas d'Água, que liga e desliga a bomba d'água de acordo com a programação dos módulos de irrigação. Os módulos, que atuam de forma independente, são programados por comunicação sem fio, baseada no SimpliciTI, um protocolo de comunicação sem fio de código aberto da Texas Instruments. / Abstract: Concerns about the future of the water resources and the value of precision agriculture products takes the farmers to look for more intelligent and precise ways to manage the water. This work presents a proposal of an automated georeferenced localized irrigation system aided by soil moisture sensor, that aims for low cost and is independent of a sensor network or a processing central. In this work it was developed an Intelligent Localized Irrigation Module, that actuates according to the informations acquired by the soil moisture sensor. It was also developed a Programming Module, responsible for the data entry and the irrigation modules programming and a Water Bomb Actuator Module, that turns on and off the water bomb according to the irrigation modules program. The independent working modules are programmed wirelessly, based on SimpliciTI, an open source wireless protocol from Texas Instruments. / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Summary: Great Podkrusnohorska spoil heaps in the Sokolov region in Western Bohemia is the largest spoil heaps in the Czech Republic, which was pour million tonnes of overburden soil surface mining of brown coal. The thesis is setting on the basic characteristics of the water regime and water balance of spoil heap soil and thus follows a series of previous works dealing with the comparative development of the reclaimed and unreclaimed area. The areas are long-term monitoring of soil moisture using a dielectric soil moisture meter total water regime was monitored by subsurface with gravitation lyzimeter, runoff and throughfall rainfall. Older unreclaimed plots as well as reclaimed plots have higher porosity, water field capacity and moistre than young sites, however there are limited by water deficiency in similatr way as young sites due to increase in wilting point. Keywords: Spoil heaps, Recultivation, Soil humidity, Water supply, Water balance

<p>Tokom tri vegetacione sezone mereni su fiziolo&scaron;ki<br />parametri: fotosinteza, transpiracija,&nbsp; efikasnost<br />iskori&scaron;tavanja&nbsp; vode (WUE), kao i parametri<br />bioprodukcije na odabranim &scaron;umskim<br />populacijama bukve&nbsp; (Fagus sylvatica&nbsp; L.), smrče<br />(Picea abies (L.) Kartsen) i jele (Abies alba Mill.),<br />čija su stani&scaron;ta na različitim nadmorskim visinama<br />sa različitom&nbsp; dostupno&scaron;ću vode u zemlji&scaron;tu.<br />Određivana je i zavisnost između položaja &scaron;umske<br />zajednice na padini planine (nadmorska visina i<br />nagib) i fotosinteze, odnosno bioprodukcije<br />biljaka. Cilj istraživanja je bio da se precizno<br />defini&scaron;e mogući dalji trend geografskog<br />pomeranja stani&scaron;ta odabranih biljnih vrsta koji je u<br />korelaciji sa morfo-fiziolo&scaron;kim&nbsp; adaptivnim<br />odgovorom biljaka na promenu ekolo&scaron;kih uslova<br />životne sredine.&nbsp; Fotosintetička aktivnost tokom<br />vegetacione sezone bila je stabilna ili se<br />povećavala pri optimalnoj vlažnosti zemlji&scaron;ta. Na<br />lokalitetima Tara i Kopaonik količina<br />atmosferskih padavina nije igrala određujuću<br />ulogu u dinamici fotosintetičke asimilacije CO₂.<br />Vlažnost zemlji&scaron;ta je na ovim lokalitetima bila<br />visoka i stabilna zbog dreniranja vode sa&nbsp; okolnih<br />brda. Registrovane razlike u dinamici fotosinteze<br />između ispitivanih vrsta povezane su sa različitim<br />životnim ciklusom listopadnih i četinarskih vrsta i<br />sa različitim fiziolo&scaron;kim adaptacionim<br />strategijama na promene faktora spolja&scaron;nje<br />sredine. Na dinamiku fotosintetičke asimilacije<br />CO_2&nbsp;signifikantno utiče prosečna temperatura<br />vazduha pre i tokom merenja, prosečna<br />osmonedeljna količina padavina pre merenja,<br />količina padavina na dan merenja, kao i<br />momentalna vlažnost zemlji&scaron;ta (MVZ). Rezultati<br />istraživanja ukazuju da će dejstvo klimatskih<br />promena biti vi&scaron;e izraženo na &scaron;umskim<br />populacijama koje se nalaze na&nbsp; vr&scaron;nim,<br />grebenskim lokalitetima većih nadmorskih visina,<br />ili na padinama planina. Su&scaron;ni periodi tokom<br />vegetacione sezone, značajan su faktor pomeranja<br />&scaron;uma planinskih lokaliteta. Bukove &scaron;ume su dobro<br />adaptirane na su&scaron;u i dobro podnose temperaturni<br />stres, međutim, dugi periodi sa oskudnim<br />padavinama izazivaju smanjenje asimilacije CO₂<br />&scaron;to ograničava značaj &scaron;uma u ublažavanju<br />klimatskih promena.</p> / <p>During three vegetation seasons,&nbsp; physiological<br />parameters, such as&nbsp; photosynthesis,&nbsp; transpiration,<br />water use efficiency&nbsp; (WUE), as well as the parameters<br />of bioproduction of the&nbsp; beech (Fagus&nbsp; sylvatica&nbsp; L.),<br />spruce (Picea&nbsp; abies&nbsp; (L.) Kartsen) and&nbsp; fir (Abies&nbsp; alba<br />Mill.)&nbsp; forest populations&nbsp; have&nbsp; been investigated<br />depending on different altitude&nbsp; mountain.&nbsp; The<br />relationship between&nbsp; the photosynthesis&nbsp; (and<br />bioproduction)&nbsp; of plants&nbsp; and the&nbsp; slope of the mountain<br />is&nbsp; also specified&nbsp; according to&nbsp; ecological parameters<br />(water&nbsp; regime and temperature.&nbsp; The aim of this<br />research is to define physiological status of forest<br />mountain ecosystems in relation to the ecological<br />conditions and predict further trend of geographic shift<br />of the habitats, which is in&nbsp; correlation with the&nbsp; plant<br />morpho-physiological adaptation responses on<br />environmental&nbsp; changes.&nbsp; Photosynthetic activity<br />during vegetation season was stable or increased&nbsp; in<br />optimal level of soil moisture&nbsp; conditions. On the<br />localities of Tara and Kopaonik the quantity of<br />atmospheric precipitation did not play a determining<br />role in the dynamics of photosynthetic assimilation of<br />CO₂. On these localities soil moisture was high and<br />stable as a result of water running off from<br />surrounding mountains.&nbsp; Detected differences in the<br />dynamics of photosynthesis of the tested species are<br />result of&nbsp; various lifecycles of&nbsp; deciduous and<br />coniferous trees and various physiological adaptation<br />strategies.&nbsp; The most influential effects on the<br />dynamics of the photosynthesis of the&nbsp; beech,&nbsp; spruce<br />and fir plants during the vegetation season were the<br />following abiotic factors: average air temperature<br />before measuring, temperature on the day of<br />measuring,&nbsp; eight-week amount of average<br />precipitation before measuring, amount of<br />precipitation&nbsp; on the day of measuring&nbsp; and&nbsp; soil<br />humidity. The analysis of the physiological parameters<br />of the beech populations of various mountain&nbsp; altitudes<br />show that even if beech is sensitive to draught it has<br />the physiological potential to keep its vitality by<br />efficient managing water.&nbsp; Effect of climatic changes<br />will be more expressed in forests that can be found on<br />high&nbsp; altitude mountain reefs and peaks.&nbsp; Beech forests<br />tolerate temperature&nbsp; and drought&nbsp; stress, but long<br />periods of&nbsp; poor&nbsp; precipitation&nbsp; cause the decrease of<br />CO_2&nbsp;assimilation which consequently decreases their<br />importance in the global reduction of atmospheric<br />CO₂,&nbsp;i.e. limits their role in the&nbsp; moderation&nbsp; of climate<br />change.</p>

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The land surface models (LSM) are the component of the numerical weather prediction and climate models that represents the processes of interaction between the biosphere and atmosphere. The need to improve the representation of bio-geophysical process stimulated the development of sophisticated parametrization. This development increased the complexity of LSMs and the number of parameters involved. Some of these parameters can be measured, but it does not ensure that the best results will be produced. Therefore, a general strategy is to use field experiments (local) to calibrate these parameters for different vegetation types, minimizing the differences between the simulated and observed value(s) of variable(s) of interest. LSMs are usually calibrated using observation of the sensible (H) and latent (LE) heat flux . Studies including soil moisture (�) in the calibration are less frequent (or restricted to the surface layer), but in forest ecosystems, under seasonal water stress, vertical soil moisture profile in vadose zone is essential for simulating transpiration, CO2 assimilation and the partition between the surface and underground flows. This paper describes the calibration of the Simple Biosphere Model (SiB2) for the Cerrado sensu-stricto, using flux measurements, soil moisture and atmospheric forcings collected in a micrometeorological tower located in Gleba Pé de Gigante, SP, in the period July 2009 to July 2012. For calibration, the SiB2 model was separated into modules that included the radiative, aerodynamic and finally, soil water processes and conductance and photosynthesis. The multi-objective calibration algorithm AMALGAM was applied to each of these modules using as objective functions: the mean square error (RMSE), Nash-Sutcliffe efficiency (NSE), the error of amplitude of the mean cycle annual (ACAM) or hourly (ACH). The calibrated variables were: albedo PAR (�PAR), global albedo (�), friction velocity (u�), net radiation (Rn), latent and sensible heat flux and total water storage (Az) up to two meters deep. Nonetheless, the modular calibration was compared with a global calibration in which only variables LE, H and Az were optimized. The calibration for radiative module allowed to reproduce the seasonal cycle and amplitude for albedo PAR, while the global albedo was lagged temporally and a slightly smaller amplitude than the observation but had considerable improvement compared with that simulated with the original parameters. The balance of radiation was reasonably simulated, with overestimation in winter and spring and it proved to be fundamentally sensitive to downward longwave radiation. The u� was slightly underestimated in the average daily cycle against to observed but had less error than the original parameters. On the other hand, the model discretization in three soil layers failed to represent the hydrological processes in the soil and surface simultaneously for Cerrado. Therefore, the soil structure was changed by introducing vertical root distribution profile, the process of hydraulic redistribution and updating the Green-Ampt infiltration scheme. These schemes were essential to the modeling of hydrologic processes of Cerrado vegetation, which is applicable to other deep root system. The global calibration fairly represented LE, H and Az, but resulted in �PAR anti-correlated, considerable underestimation of the � and u�, also in inconsistent partition for evapotranspiration components. / Os modelos da superfície terrestre (LSMs) são a componente dos modelos numéricos de previsão numérica do tempo e clima que representam os processos de interação entre a biosfera e atmosfera. A necessidade de aperfeiçoar a representação dos processos biogeofísicos estimulou o desenvolvimento de sofisticadas parametrizações, aumentando a complexidade dos LSMs e o número de parâmetros. Alguns desses parâmetros podem ser medidos, mas isso não assegura que melhores resultados serão produzidos devido a erros de amostragem e representatividade das condições experimentais (variabilidade espacial, vertical e a heterogeneidade de superfície). Portanto, uma estratégia geral é usar experimentos de campo (locais) para calibrar esses parâmetros para diferentes tipos de vegetação, minimizando as diferenças entre os valores simulados e observados da(s) variável( is) de interesse. LSMs são geralmente calibrados usando observações dos fluxos de calor sensível (H) e latente (LE). Enquanto estudos que incluam a umidade do solo (�) na calibração são menos frequentes (ou restritos a camada superficial do solo), mas em ecossistemas florestais sujeitos a estresse hídrico sazonal (zona radicular profunda, heterogeneidade vertical) o perfil vertical da umidade do solo na zona vadosa é essencial para simulação da transpiração, assimilação de CO2 e a partição entre os escoamentos superficial e subterrâneo. Esta dissertação descreve a calibração do modelo Simples da Biosfera (SiB2) para o Cerrado sensu-stricto, utilizando medidas de fluxos, umidade do solo e forçantes atmosféricas coletadas em uma torre micrometeorológica localizada na Gleba Pé de Gigante, SP, no período de Julho de 2009 até Julho de 2012. Para a calibração, o modelo SiB2 foi separado em módulos que incluíram os processos radiativos, aerodinâmicos e por último os processos hídricos e de condutância e fotossínteses. O algoritmo de calibração multiobjetivo AMALGAM foi aplicado a cada um desses módulos utilizando nas funções objetivo a raiz do erro quadrático médio (RMSE), eficiência de Nash-Sutcliffe (NSE), erro da amplitude do ciclo médio anual (ACAM) ou horário (ACH). As variáveis calibradas foram: albedo PAR (�PAR), albedo global (�), velocidade de fricção (u�), saldo de radiação (Rn), fluxo de calor latente e sensível e armazenamento total de água (Az) até dois metros de profundidade. No entanto, a calibração por módulos foi comparada com uma calibração global na qual somente foram otimizadas as variáveis LE, H e Az. A calibração do módulo radiativo permitiu reproduzir o ciclo sazonal e amplitude do albedo PAR, enquanto o albedo global ficou defasado temporalmente e com amplitude levemente menor que a observação, porém teve razoável melhora quando comparado com o simulado com os parâmetros originais. O saldo de radiação foi razoavelmente simulado, apresentando superestimativa no inverno e primavera e mostrou-se sensível fundamentalmente à parametrização de radiação de onda longa incidente. Enquanto a u� subestimou levemente o ciclo médio diário observado mas teve erro menor que a configuração original. Por outro lado, a discretização de três camadas do solo do modelo não conseguiu representar os processos hidrológicos no solo e superfície simultaneamente do Cerrado. Mudou-se, portanto, a estrutura de solo, introduzindo o perfil vertical de distribuição de raízes, o processo de redistribuição hidráulica e a atualização do esquema de infiltração Green-Ampt. Estes esquemas foram fundamentais para a modelagem dos processos hidrológicos da vegetação Cerrado, o que é aplicável a outras de sistema radicular profundo. A calibração global representou razoavelmente LE, H e Az, porém resultou em �PAR anti-correlacionado, subestimativa considerável do � e u�, além de partição inconsistente nas componentes da evapotranspiração.

This diploma thesis focuses on the use of thermogravimetry as quick and low-cost method in the analysis of soil quality. Most of the currently used methods for analyzing some soil properties are, unlike thermogravimetry, demanding especially for pretreatment and analysis time. Previous research has shown an interesting correlation between thermogravimetry data and some soil properties, but to obtain these correlations, it is necessary to keep the analyzed soils at 76% relative humidity. The aim of this work was to determine whether similar correlations can also by achieved at lower relative humidities. Therefore, soil samples in this work were thermogravimetrically analyzed at 43% relative humidity. That humidity is closer to laboratory conditions and it is also easier to be reached by most of commercially available thermogravimeters. Next aim of this thesis was to find whether thermogravimetric data correlate with other soil properties, especially microbiological indicators of soil quality. Results showed that thermogravimetry of soil samples correlates with standard methods even at 43% humidity. Furthermore, it was found that they also correlate with selected microbiological parameters, such as anaerobic ammonification or urease activity. These results suggest the possibility of using thermogravimetry analysis at broader spectrum of soil properties, without the need for pretreatment of samples and at different (relevant) soil moisture.

Cette thèse porte sur l'impact du changement climatique du à des gaz à effet de serre sur l'état et l'évolution du pergélisol dans le nord canadien. Le pergélisol se retrouve sur la moitie du territoire canadien et un changement de son état actuel se répercutera dans toutes les sphères d'activité, sur la biosphère et sur l'environnement en général. Malgré l'importance évidente du sujet, il n'y a pas une idée précise comment le pergélisol réagira au changement climatique et jusqu'où la couche pergélisolée sera perturbée. Cette thèse explore ce sujet en utilisant une approche méthodologique s’inspirant de celui du modèle canadien d'évolution de pergélisol (TTOP) et avec une approche théorique basée sur la théorie des systèmes neuronaux complexes. L’objectif général de cette thèse est d’améliorer le modèle canadien d’évolution du pergélisol (TTOP - Temperature on the Top Of Permafrost) créé par Smith et Riseborough en 1996, tant dans sa structure de calcul, que dans sa résolution spatiale et de déterminer l'évolution du pergélisol dans la zone d'étude pour la période 2010-2100. Cette zone est située dans le Bassin Mackenzie (T.N-O) sur un transect nord-sud de 1440 x 720 km. Le premier objectif de recherche est de produire les cartes des valeurs annuelles de température à la partie supérieure du pergélisol de 2010 à 2100 en utilisant un modèle amélioré d'évolution du pergélisol (TTOP-A). Par la suite, ces valeurs sont comparées à celles obtenues par Smith et Riseborough (1996). Les valeurs de température de l'air pour cette période sont fournies par les scénarios d'évolution climatique MCCG3 SRES A1B, MCCG3 SRES A2 et MCCG3 SRES B1. Dans un deuxième temps, cette thèse a pour objectif la production des cartes d'épaisseur de pergélisol jusqu'en 2100 à une résolution spatiale de 25 km. Plus précisément, on détermine l'évolution des valeurs d'épaisseur de pergélisol pour les trois scénarios climatiques mentionnés antérieurement. De plus, l'étude propose: i) une nouvelle méthode de désagrégation des données climatiques en utilisant un Modèle Stochastique Déterminé, ii) l'intégration de la carte de type de sol, iii) l'intégration des valeurs d'humidité dans le sol, iv) l'intégration des valeurs d'épaisseur de la couche nivale et v) l'intégration des données de télédétection (SSM/I). De façon générale, les résultats obtenus par le modèle TTOP-A révèlent que les valeurs moyennes de température à la surface du pergélisol suivent de près les valeurs de température de l’air et qu'elles sont semblables aux celles trouvées par Smith et Riseborough (1996) et Heginbottom et coll. (1995). De plus, les différences des valeurs de température à la surface de pergélisol entre 2010 et 2100 s'inscrivent dans l'écart des valeurs publié par le Groupe d'Experts Intergouvernemental sur l'Évolution du Climat (GIEC, 2007). Concernant le deuxième objectif de cette thèse, la dynamique spatiotemporelle du pergélisol jusqu'en 2100 démontre que, dans la zone d'étude, la superficie perturbée par le réchauffement climatique sera de 37 %, 60 % et 29 % selon les scénarios MCCG3 SRES A1B, MCCG3 SRES A2 et MCCG3 SRES B1 respectivement. Selon les scénarios mentionnés antérieurement, la couche pergélisolée à l'intérieur de cette zone disparaîtra dans une proportion de 20 %, 32 % et 18 % respectivement. Ces résultats nous laissent croire que les prévisions faites par Smith et Riseborough ont été surévaluées dans le contexte de deux des trois scénarios climatiques actuels par rapport à celui de 1996. Finalement, cette étude démontre que la méthode de désagrégation des données en utilisant les réseaux neuronaux dans un Modèle Stochastique Déterminé donne de bons résultats et elle représente une option fiable qui se prête à des généralisations à grande échelle. / This thesis explores the potential impacts of a climate change due to the greenhouse gases on the state and the evolution of the permafrost in the Canadian North. The permafrost represents the half of the Canadian national territory and a change of its current state will echo in all spheres of activity, on the biosphere and on the environment generally. In spite of the evident importance of the subject, there is no precise idea as to how the permafrost will react to the climate change and to what extent the frozen layer will be disrupted. This thesis investigates this problem by using a methodological approach inspired by the Canadian model on the evolution of permafrost (TTOP) coupled with a theoretical approach based on the theory of the complex neuronal systems. The general objective of this thesis is to improve the Canadian model of evolution of permafrost (TTOP-Temperature one the Top Of Permafrost) created by Smith and Riseborough in 1996, its structure of computation, spatial resolution and to determine the state of the permafrost in the study area between 2010 and 2100. The study zone is situated in the Mackenzie Basin (N-W.T) on a north-south transect of 1440 by 720 km. The first objective of the research is to derive maps of the annual values of temperature on the top of the permafrost from 2010 to 2100 by using an improved dynamic model of the evolution of permafrost (TTOP-A). Thereafter, these values are compared with those obtained by Smith and Riseborough (1996). The values of the evolution of air temperature for this period are supplied by the climatic scénarios CGCM3 SRES A1B, CGCM3 SRES A2 and CGCM3 SRES B1. Secondly, this thesis has as an objective the production of the maps of the thickness of permafrost for 2100 with a spatial resolution of 25 km. More exactly, we determine the evolution of the values of thickness of permafrost for the three climatic scénarios mentioned above. Furthermore, the study proposes: i) a new method for downscaling of climate data by using a Determined Stochastic Model, ii) the integration of soil type, iii) the integration of the soil humidity, iv) the integration of the values of thickness of the snow layer and v) the integration of remote sensing data (SSM/I). As a rule, the results obtained by the TTOP-A model reveal that the mean values of temperature at the surface of the permafrost follow closely the values of air temperature and that they are similar to those found by Smith and Riseborough (1996) and Heginbottom and coll. (1995). Also, the differences of the values of temperature on the surface of permafrost between 2010 and 2100 are similar to the values published by the Intergovernmental Panel on Climate Change (IPCC). Concerning the second objective of this thesis, the spatio-temporal dynamics of the permafrost until 2100 demonstrates that, in the study zone, the surface perturbed by global warming will be 37 %, 60 % and 29 % according to the scénarios CGCM3 SRES A1B, CGCM3 SRES A2 and CGCM3 SRES B1 respectively. The permafrost layer inside this zone will disappear by 20 %, 32 % and 18 % according to the scénarios mentioned before. These results lead us to believe that the estimations made by Smith and Riseborough were overvalued in the context of two of three current climates scénarios compared to that of the 1996. Finally, this study demonstrates that the method of downscaling of climate data using the neuronal network within a Determined Stochastic Model gives good results and it represents a reliable option which lends itself to large-scale generalizations. / Les fichiers video (d'animation) sont dans un format Windows Media (.wmv)

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<p>&nbsp; &nbsp; U radu je ispitan uticaj vodnog deficita na fiziolo&scaron;ke osobine klonova crne topole i<br />populacija hrasta lužnjaka i cera, kao i mogućnost oporavka ovih biljaka nakon ponovnog uspostavljanja optimalnog vodnog režima. Cilj istraživanja je bio da se ukaže na potencijal ispitivanih genotipova topole i hrastova za opstanak u&nbsp; promenljivim uslovima životne sredine, u skladu sa aktuelnim klimatskim promenama koje uključuju smanjenje količine padavina i ograničenu dostupnost vode. Dobijeni rezultati su pokazali specifično variranje ispitivanih morfo-anatomskih, fiziolo&scaron;kih i biohemijskih parametara koje je zavisilo od momentalne vlažnosti zemlji&scaron;ta na primenjenom tretmanu (kontrola, su&scaron;a praćena oporavkom, konstantna su&scaron;a) i od genotipa biljke.<br />&nbsp; &nbsp; Negativan uticaj vodnog&nbsp; deficita na tretmanu konstantne su&scaron;e je u najmanjoj meri bio ispoljen na rastenje klona topole X/32, populaciju hrasta lužnjaka L1 i populaciju hrasta cera C1. Indeks tolerancije na stres izračunat na osnovu visine biljke (PHSI) takodje je potvrdio dobru morfolo&scaron;ku prilagodjenost pomenutih genotipova<br />na uslove su&scaron;e. Dobijene vrednosti indeksa stoma ukazuju da vodni status ispitivanih populacija hrastova nije bio naroĉito pogodjen vodnim deficitom na su&scaron;nim tretmanima.<br />&nbsp; &nbsp; Tretman konstantne su&scaron;e je u oba ogleda&nbsp; doveo do najvećeg smanjenja vrednosti<br />parametara razmene gasova kod skoro svih genotipova. S druge strane, primenjeni su&scaron;ni tretmani nisu uslovili smanjenje sadržaja fotosintetiĉkih pigmenata, kao ni parametra Fv/Fm, kod većine ispitivanih biljaka. U odnosu na kontrolu, sadržaj prolina u listovima ispitivanih biljaka na tretmanu konstantne su&scaron;e bio je&nbsp;&nbsp;&nbsp; znaĉajno povećan, a aktivnost enzima nitrat-reduktaze značajno smanjena, kod većine genotipova.<br />&nbsp; &nbsp; Genotipovi kod kojih u uslovima jakog vodnog deficita nije do&scaron;lo do značajne promene većine ispitivanih morfo-anatomskih, fiziolo&scaron;kih i biohemijskih parametara mogu biti od velike važnosti kad je u pitanju njihov odabir i upotreba za uspe&scaron;no po&scaron;umljavanje su&scaron;nih stani&scaron;ta, kojih će biti sve vi&scaron;e usled negativnog uticaja brojnih ekolo&scaron;kih činilaca nastalih kao posledica klimatskih promena.</p> / <p>The impact of water deficit and recovery on physiological features of the black poplar clones, as well as of the oaks populations were analyzed. The aim of this research was to indicate the potential of the studied genotypes for survival under changing environmental conditions, in accordance with current climate changes, which include the reduction in amount of rainfall and limited water availability. Obtained results have shown a specific variation of studied morpho-anatomical, physiological and biochemical parameters which depended on soil humidity on the applied treatment (control, drought followed by recovery and permanent drought), as well as on plant genotype.</p><p>Water deficit on permanent drought treatment had little negative effect on plant growth of poplar clone X/32, as well as oak populations L1 and C1. Plant height stress tolerance index also confirmed good morphological adaptation to drought of these genotypes. Stomatal index was not negatively affected by water deficit in oak plants.&nbsp;&nbsp;&nbsp;&nbsp; In both experiments, a permanent drought treatment led to the largest reduction in the values of gas exchange parameters in almost all genotypes.</p><p>On the other hand, concentration of&nbsp; photosynthetic pigments was not considerably decreased in plants exposed to water deficit, as well as the parameter Fv/Fm, in most examined plants. Compared to the control, the impact of permanent drought treatment&nbsp; on biochemical parameters was expected, in the most cases.&nbsp;&nbsp;&nbsp;&nbsp; Compared to the control, proline content in leaves of most examined genotypes was significantly increased on permanent drought treatment, while nitrate reductase activity was significantly decreased.</p><p>Examined genotypes exhibiting slight or no reduction in values of the most&nbsp; examined parameters during severe&nbsp; drought stress, could be used for afforestation in arid sites. Arid habitats appeared to be more numerous due to the effects of global climate changes.</p>