O hábito de crescimento influencia o balanço entre o desenvolvimento vegetativo e o reprodutivo das plantas. Este, por sua vez, está diretamente vinculado a diversas variáveis de interesse agronômico, como produtividade e consumo de água. Em tomateiro, existem três hábitos de crescimento conhecidos: determinado, indeterminado e semi-determinado, sendo esse último na verdade determinado, porém com uma extensão do ciclo vegetativo. Cultivares de crescimento determinado são largamente utilizadas para produção de tomates destinados à indústria (molhos e ketchups), e as indeterminadas destinadas ao consumo in natura. Por outro lado, genótipos de crescimento semi-determinado, embora ainda sejam pouco explorados, apresentam-se como ótimas opções tanto para indústria quanto para o consumo in natura. Diante disto, o presente trabalho teve por objetivo avaliar a implicação do hábito de crescimento semi-determinado no desempenho produtivo e na eficiência no uso da água de plantas de tomateiro. Para tal, genótipos com diferentes hábitos de crescimento foram produzidos, por meio de introgressões de variações alélicas que afetam o hábito de crescimento das plantas, no background genético da cultivar miniatura de tomateiro Micro-Tom (MT). A caracterização desses genótipos demonstrou que os materiais de crescimento semideterminado apresentam um atraso no florescimento, emitindo em média uma folha a mais antes da formação da primeira inflorescência. Além disso, verificasse que essas plantas apresentam uma altura intermediária entre genótipos de crescimento determinado e indeterminado, aos 50 dias após a semeadura. Já para características agronômicas, constatou-se um aumento significativo na produtividade e no conteúdo de sólidos solúveis totais (brix) nos frutos dos genótipos de crescimento semi-determinado em comparação com o de crescimento determinado. Os dados sugerem que esse efeito seja resultante de um balanço mais equilibrado entre o desenvolvimento vegetativo e o reprodutivo, evidenciado pela ausência de diferença significativa na partição de massa seca oriunda do desenvolvimento vegetativo e do reprodutivo nesses genótipos, quando comparados aos genótipos de crescimento determinado e indeterminado. A eficiência no uso da água (EUA) foi avaliada tanto gravimetricamente (massa seca total produzida por quantidade de água transpirada), quanto através de discriminação isotópica. Os genótipos de crescimento semi-determinado apresentaram maior EUA do que os genótipos determinado e indeterminado aos 50 dias após a semeadura. Curiosamente, as plantas de crescimento semi-determinado mostraram-se mais resistentes, quando submetidas a um estresse de seca, que o genótipo de crescimento determinado utilizado como controle nas avaliações. Entretanto, são necessários estudos para elucidar o mecanismo envolvido nesta resistência. Em conclusão, os resultados aqui apresentados sugerem que os genótipos de crescimento semi-determinado atingiram o balanço ótimo entre desenvolvimento vegetativo e reprodutivo, de forma a aumentar concomitantemente, produtividade, conteúdo de brix nos frutos, e eficiência no uso da água. / Growth habit influences the balance between vegetative and reproductive development of plants. This, in turn, is directly linked to several variables of agronomic interest, such as yield and water-use efficiency (WUE). In tomato, there are three growth habits: determinate, indeterminate and semi-determinate, the latter being actually determinate, but with an extension of the vegetative cycle. Cultivars of determinate growth are widely used for processing-tomato industry (sauces and ketchups), and indeterminate for in natura consumption (production to salads). On the other hand, semi-determinate growth genotypes, although are still poorly explored, they present an excellent option for both the industry and in natura consumption. Thus, the aim of the present study was to evaluate the implication of the semi-determinate growth habit in productive performance and in WUE of tomato plants. For this reason, genotypes with different growth habits were produced through introgression of allelic variations that affect the plants growth habit, in the genetic background of the tomato cultivar Micro-Tom (MT). The characterization of these genotypes showed that the semi-determinate growth materials exhibit a delay in flowering, producing on average one extra leaf before the first inflorescence formation. In addition, this architecture presents an intermediate height between determinate and indeterminate growth genotypes, 50 days after sowing. As for agronomic traits, we found a significant increase in yield and total soluble solids content (brix) in the fruits of semi-determinate growth genotypes compared with determinate growth. Our data suggest this effect is resulting from a more balanced vegetative and reproductive development, evidenced by the absence of significant difference on the dry matter partition derived from the vegetative and reproductive development in these genotypes, when compared to determinate and indeterminate growth genotypes. WUE was evaluated both gravimetrically (dry mass produced per amount of water transpired), and through isotopic discrimination. The semideterminate growth genotypes showed higher WUE than determinate and indeterminate genotypes at 50 days after sowing. Interestingly, the plants of semideterminate growth were more resistant than determinate growth genotype used as control, when exposed to drought stress. However, studies are needed to elucidate the mechanism involved in this resistance. In conclusion, the results presented here suggest that the genotypes of semi-determinate growth reached the optimal balance between vegetative and reproductive development, in order to increase concomitantly, productivity, brix content in the fruits, and WUE.

Cette thèse visait à étudier la variabilité génétique et plasticité phénotypique de la vulnérabilité à la cavitation chez le hêtre (Fagus sylvatica L.). A cette fin, nous avons tout d’abord testé les variations dues à la méthodologie de mesure de la vulnérabilité à la cavitation. Notre étude a montré que les variations de vulnérabilité à la cavitation au cours du temps sont faibles. Néanmoins, il est préférable d’éviter de récolter les échantillons durant le début de la période de formation du bois. Par ailleurs il est possible de conserver au frais les échantillons sans dégrader les mesures durant au moins un mois. Nos résultats montrent également que la vulnérabilité à la cavitation peut être variable aussi bien au sein d’un même arbre qu’entre populations in situ. Ensuite, nous avons voulu déterminer la part de plasticité phénotypique de la part de variabilité génétique dans la variabilité de la vulnérabilité à la cavitation. Pour cela nous avons étudié 17 populations de hêtre venant de toute l’Europe et poussant dans une plantation comparative. Parmi les 17 populations 6 d’entre elles ont été étudiées dans trois plantations comparatives différentes (France, Espagne et Slovaquie). Nos résultats indiquent que chez le hêtre la vulnérabilité à la cavitation varie considérablement au sein de chaque population. Ils indiquent également que l’on observe peu de différenciation génétique entre populations. Les résultats montrent également que la plasticité phénotypique de la vulnérabilité à la cavitation est importante entre les plantations, et que le degré de cette plasticité peut varier d’une population à l’autre. Pour finir, nous avons regardé s’il existait des relations entre la vulnérabilité à la cavitation et des paramètres d’efficience hydraulique ainsi qu’avec l’efficience d’utilisation de l’eau. Nos résultats ne permettent pas de mettre en évidence des preuves d’un trade-off entre l’efficience et la sureté du xylème. / This work aimed at studying the genetic variability and the phenotypic plasticity of vulnerability to cavitation in beech (Fagus sylvatica L.). We tested the variations due to the methodology of measuring vulnerability to cavitation. Our study showed that the variations in vulnerability to cavitation over time are low. However, it’s better to avoid collecting samples during the period of initial wood formation. Furthermore it’s possible to store samples without degrading measures for during one month. Our results also show that vulnerability to cavitation can be variable both within the same tree and between populations in situ. We determined the proportion of phenotypic plasticity and the proportion of genetic variability in the variability of vulnerability to cavitation. For this we studied 17 beech populations from all Europe and growing in a common garden. Among the 17 populations 6 of them have been studied in three different common gardens (France, Spain and Slovakia). Our results indicate that for beech, vulnerability to cavitation varies considerably within populations. They also indicate that there are few genetic differentiations between populations. The results show that the phenotypic plasticity of vulnerability to cavitation is important among common garden, and the degree of this plasticity can vary between populations. To complete our study, we looked at the relationships between vulnerability to cavitation and hydraulic efficiency parameters and with the water use efficiency. Our results do not reveal evidence of relationships vulnerability to cavitation and other physiological traits.

Le potassium (K) est un élément majeur connu pour contribuer à la résistance des plantes à la sècheresse. L'étudede son influence sur la réponse physiologique du maïs (Zea mays L.) sous contrainte hydrique est essentiellepour prédire la future productivité dans un contexte de changements climatiques, en particulier de la diminutiondes précipitations. Des modalités d'apports en K et en eau ont été croisées et soumises à des plants de maïs,élevés en condition contrôlées ou cultivés au champ. La croissance (biomasses aériennes et racinaires,rendements en grain) ainsi que les mécanismes écophysiologiques du métabolisme carboné (photosynthèse,transport des sucres) et du statut hydrique (transpiration, conductance stomatique, potentiels hydriques) ont étéétudiés. L'apport de K a contribué à l'augmentation de la croissance, le développement et le rendement grain quelque soit le régime hydrique imposé au maïs et les conditions d'expérimentation. Les résultats attendus sur lameilleure régulation stomatique en cas de déficit hydrique sont moins évidents. L'effet du stress hydrique ou dela déficience en K tendent à diminuer la photosynthèse. Cependant, ces effets ressortent plus sur les feuillesâgées que sur les feuilles jeunes. Dans ces mêmes conditions, le transport des sucres ne semble pas être unélément limitant de la croissance. Plusieurs résultats convergent pour attribuer au K un rôle dans la maîtrise despertes en eau (par unité de surface foliaire) et sur la meilleure efficience d'utilisation de l'eau. Néanmoins, cetteefficience est imputée à des meilleurs rendements, liés à une surface foliaire plus importante, et non pas à unemoindre consommation de l'eau. / Potassium (K) is a major nutrient known to help plants resist drought. In the context of climate change,quantifying the role of K on maize physiological acclimation to reduced precipitations is essential to betterpredict future productivity. Maize (Zea mays L.) plants grown under controlled or field conditions weresubmitted to different K and water levels. Plant growth (shoot and root biomass, grain yield) as well as plantwater status (transpiration, stomatal conductance, water potential) and ecophysiological mechanisms of Carbonmetabolism (photosynthesis, sugar transport) were studied. Regardless of the water regime and experimentalconditions, K nutrition increased growth and whole-plant development and improved grain yield. The effect ofwater stress on stomatal regulation was not straightforward and depended on the level of K fertilization. Theeffects of water or K deficit tend to decrease photosynthesis. Drought or K nutrition affected more leafphotosynthesis in old than in young leaves, and sugar transport did not seem to be a growth limiting factor. Ourresults demonstrated a strong effect of K on biomass production and a higher water use efficiency with less of animpact on leaf-level physiology. This better water use was mainly the consequence of the positive effect of leafarea on yield, and not due to a reduce water use.

A water footprint is a tool for assessing the impacts of freshwater use by mapping the water use of the production of a good or a service, a process in a production chain, a business or even of a whole country. One of the most commonly used methods for calculating the water footprint was developed by the Water Footprint Network (WFN). The objective of this study was to account for the water footprint of the production of coffee in the area of Miraflor, Nicaragua, using the WFN method. The study aimed to highlight where improvements can be made regarding water resources management, both with respect to the quantity of the water appropriated in the different process steps, as well as concerning the treatment of residues of the coffee production. The results of the study show a water footprint of 20 049 m3 per ton of harvested coffee in Miraflor. This equals a consumption of more than 6 000 000 m3 of water when considering the overall production of the harvest of 2015/2016. The results pinpoint the growing phase as crucial with 98.1 % of the total water footprint. Nicaragua and the region where Miraflor is located are having increasing problems with water scarcity due to drought and contamination of water resources. Together with these circumstances, the results of the study show that the current management should be improved in order to minimize the impacts on local water resources and the environment. It is mainly the application of pesticides and fertilizers in the cultivation of the coffee that give rise to the large water footprint. Furthermore, the current management violates the law restricting the discharge of effluent waters from coffee processing plants. Another important factor contributing to the water footprint yields in the consumption of rainwater via evapotranspiration by the crops in field. In order to reduce the water footprint there should be a more conscious use of pesticides and fertilizers as well as a development in the treatment of the effluent water. The latter factor can be elaborated by considering new installations where even smaller ones probably could make a considerable change. Other management practices to decrease the water footprint consist of generating a higher yield per hectare of land. / Vattenfotavtryck är ett verktyg för att bedöma miljöpåverkan från användningen av vatten. Med ett vattenfotavtryck kartläggs hur vatten används för produktionen av en vara, för en process i en produktionskedja, ett företag eller för ett helt land. En av de mest använda metoderna för beräkning av vattenfotavtryck utvecklades av Water Footprint Network (WFN). Syftet med denna studie var att genom användning av WFN:s metod beräkna vattenfotavtrycket för produktionen av kaffe i området Miraflor i Nicaragua. Studien ämnade visa var förbättringar kan göras i vattenresurshanteringen, både vad gäller mängden vatten som används i de olika produktionsstegen som i behandlingen av restvattnet från kaffeproduktionen. Resultatet från studien visar ett vattenfotavtryck på 20 049 m3 per ton skördat kaffe i Miraflor. Sett till hela skörden för säsongen 2015/2016 ger detta ger en total konsumtion av mer än 6 000 000 m3 vatten. Resultatet påvisar att vegetationsperioden är den i särklass största bidragande faktorn till kaffeproduktionens vattenfotavtryck med 98,1 % av det totala avtrycket. Nicaragua och regionen där Miraflor ligger har alltjämt ökande problem med vattenbrist på grund av torka och föroreningar av vattenresurser. Studiens resultat visar tillsammans med denna bakgrund att nuvarande tekniker i kaffeproduktionen i Miraflor bör förbättras för att minimera konsekvenser för lokala vattenresurser och miljön. Främst är det användningen av bekämpningsmedel och gödsel som ger upphov till det stora vattenfotavtrycket. Kaffeproduktionen orsakar därtill överträdelser av gällande bestämmelser om värden på vattenkvalitetsparameterar i restvatten från kaffeproduktion. En ytterligare betydande faktor för vattenfotavtrycket som påvisas i studien är konsumtionen av regnvatten via evapotranspiration från grödorna i fält. För att minska vattenfotavtrycket bör i första hand en mer medveten användning av bekämpningsmedel och gödsel införas. Därtill bör det ske en förbättring i hanteringen av utsläppsvatten. Den senare faktorn kan utvecklas genom att nya installationer införs där även mindre sådana troligtvis skulle ge en betydande skillnad. Andra metoder för att minska vattenfotavtrycket ligger i att generera en högre skörd per hektar land.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The irrigation of the rice crop is essential for good plant growth, assisting in achieving high grain yield levels. However, it results in large water volume used, thus the efficiency of water use is a major challenge to the sustainability of the crop. In this matter, early irrigation withholding can be considered an option for saving water. However, this practice can prejudice the quality of the crop, in yield and grain quality. In rice cultivars with large panicles, as in the case of hybrid rice, early withholding may be reflected in the quality of the grains from the bottom of the panicle, due to the difficulty of kernel filling in this region. Research was conducted during the growing seasons 2011/12 and 2012/13 , in order to verify the effect of anticipated moments of withholding irrigation on yield and water use efficiency ( Chapter II ) , and grain quality ( Chapter III ) of two rice cultivars . The experiments were conducted in the floodplains of the Departamento de Fitotecnia of the Federal University of Santa Maria (UFSM), using the experimental design of randomized blocks with four replications. Each experiment was composed of the factorial design appropriate to the factorsconsidered. Early withholding irrigation reduces the volume of water used in the rice crop, but depending on the moment and the cultivar, it can reduce productivity. For withholding irrigation performed before the recommended time it should be taken into account the cultivar, soil type and possible rainfall after the end of irrigation. Harvests with lower humidity than that recommended by research show a reduction in milling quality. Early withholding does not affect the milling quality, translucency, opaque and chalky grains; however, there was no difference in quality between the studied cultivars. / A irrigação da lavoura de arroz é fator imprescindível para o bom desenvolvimento da planta, auxiliando na obtenção de elevados níveis de rendimento de grãos. Entretanto resulta em grande volume de água utilizado, sendo a eficiência de uso de água um dos grandes desafios para a sustentabilidade da cultura. Neste sentido, a supressão antecipada da irrigação pode se constituir num aspecto de economia no uso de água. No entanto, essa prática pode comprometer a qualidade da lavoura no que se refere ao rendimento e à qualidade dos grãos. Em cultivares de arroz com características de panícula grande, como no caso do arroz híbrido, a supressão antecipada pode se refletir na qualidade dos grãos da parte inferior da panícula, em função da dificuldade do enchimento dos grãos nesta região. As ações de pesquisa foram conduzidas a campo durante as safras de cultivo de 2011/12 e 2012/13, com objetivo de verificar o efeito de momentos de supressão antecipada da irrigação no rendimento e na eficiência de uso da água (Capítulo II), e na qualidade dos grãos (Capítulo III) de dois cultivares de arroz irrigado. Os experimentos foram conduzidos a campo na área de várzea do Departamento de Fitotecnia da Universidade Federal de Santa Maria (UFSM), utilizando o delineamento experimental de blocos ao acaso com quatro repetições. Cada experimento foi constituído pelo delineamento fatorial adequado aos fatores em análise. A supressão antecipada da irrigação reduz o volume de água utilizado na lavoura, mas dependendo da época e do cultivar utilizado, pode reduzir a produtividade. Para a supressão da irrigação realizada antes da época recomendada deve-se levar em consideração o cultivar, tipo de solo e a possível precipitação pluvial após o término da irrigação. Colheitas realizadas com grau de umidade abaixo do preconizado pela pesquisa apresentam redução no rendimento de grãos inteiros. A supressão antecipada não interfere na qualidade de grãos inteiros, vítreos, opacos e gessados, no entanto, há diferença de qualidade entre os cultivares pesquisados.

The production potential of the sugar-alcohol market and increased demand for ethanol makes the sugarcane the most important source of energy biomass for Brazilian agribusiness. This study aimed to evaluate the technical and economic performance of the culture of sugarcane under different levels of supplemental irrigation management for the production of ethanol in the Central Region of RS. The test was developed in the experimental area at the Polytechnic School of the Federal University of Santa Maria-RS in agricultural crops in the years 2013-2014 and 2014-2015. The treatments consisted of four blades of supplemental irrigation: 30, 60, 90 and 120% with control without irrigation. The variety used was RB93-5581 early cycle, planted on November 14, 2013. The experimental design was a randomized block design with six replications. Each experimental unit consisted of 4 rows with a spacing of 1 m and 5 m in length, each block of 20 m2 and a total area of 600 m2. Irrigation management was based on crop evapotranspiration, according to the methodology proposed by FAO. The irrigation system used was located drip between spacing each emitter and 0.2 m flow of 0.8 L h-1, and the frequency of irrigation was every seven days. It was carried out chemical analysis and physical soil. The monitoring of soil moisture was the time domain reflectometry (TDR). The following parameters were evaluated: tillering, plant height, diameter, leaf area, total weight, dry weight, yield, technological parameters, was also carried out the economic viability. The highest yield was in ratoon cane, with 190 t ha-1 in treatment 60% of ETc and the lowest yield was in the plant cane in the treatment of to rainfed 158.80 t ha-1. The difference between the highest and the lowest yield was approximately 11% and 7% in plant cane and tamp respectively. The rate of technical efficiency was maximum yield in 78% of ETc. The total mass and obtain dry mass increment of 20% to 25% by ratoon cane, respectively. The largest number of tillers, leaf area and the number of green leaves was in the treatment 120% of ETc. The deficit and excess moisture affected the number of tillers, plant height, the stalk diameter, leaf area, total mass, dry matter, yield and technological parameters for the production of ethanol. In sugarcane plant in rainfed and irrigated, the variable cost represented 54.40% and 66.81% and the fixed cost of 45.60% and 33.19%, respectively. The difference in the cost of production in rainfed and irrigated was 27.23% and 57.20% for the plant cane and tamp respectively. Presented economic viability, sugarcane grown in rainfed and 60% of ETc, with differences in the cost of production and net profit of 53.94% and 52.20%, with financial return in the year of implementation and 4 years and 4 months, respectively. / O potencial de produção do mercado sucroalcooleiro e o aumento na demanda por etanol fazem da cana-de-açúcar a mais importante fonte de biomassa energética para a agroindústria brasileira. Esse estudo teve como objetivo avaliar o desempenho técnico e econômico da cultura da cana-de-açúcar submetida a diferentes níveis de manejo de irrigação suplementar para a produção de etanol na Região Central do RS. Desenvolvido na área experimental do Colégio Politécnico da Universidade Federal de Santa Maria-RS nas safras agrícolas nos anos 2013-2014 e 2014-2015. Os tratamentos foram compostos por quatro lâminas de irrigação suplementar: 30, 60, 90 e 120% da ETc e com testemunha sem irrigação. A variedade utilizada foi de ciclo precoce RB93-5581, plantada em 14 de novembro de 2013. O desenho experimental foi blocos ao acaso, com seis repetições. Cada unidade experimental foi constituída por 4 linhas com espaçamento de 1 m e 5 m de comprimento, cada bloco com 20 m2 e a área total de 600 m2. O manejo da irrigação foi realizado com base na evapotranspiração da cultura, conforme a metodologia proposta pela FAO. O sistema de irrigação utilizado foi localizado por gotejamento, com espaçamento entre cada emissor de 0,2 m e vazão de 0,8 L h-1 e a frequência de irrigação foi a cada sete dias. Foi realizada a análise química e física do solo. O monitoramento da umidade do solo foi pela reflectômetria no domínio do tempo (TDR). Avaliaram-se os seguintes parâmetros: perfilhamento, altura das plantas, diâmetros, área foliar, massa total, massa seca, rendimento, os parâmetros tecnológicos e, também foi realizado a viabilidade econômica. O maior rendimento foi na cana soca, com 190 t ha-1, no tratamento 60% da ETc e, o menor rendimento foi na cana planta, no tratamento de sequeiro, de 158,80 t ha-1. A diferença entre o maior e o menor rendimento foi de aproximadamente 11% e 7%, na cana planta e soca, respectivamente. A taxa da máxima eficiência técnica foi no rendimento de 78% da ETc. A massa total e a massa seca obtiverem incremento de 20% e 25% em cana soca, respectivamente. Os maiores número de perfilhos, de área foliar e de número de folhas verdes foi no tratamento 120% da ETc. O deficit e o excesso de umidade afetaram o número de perfilhos, a altura da planta, os diâmetros do colmo, a área foliar, a massa total, a massa seca, o rendimento e os parâmetros tecnológicos para a produção de etanol. Na cana planta em sequeiro e sob irrigação, o custo variável representou 54,40% e 66,81% e o custo fixo de 45,60% e 33,19%, respectivamente. A diferença do custo de produção em sequeiro e sob irrigação foi de 27,23% e 57,20%, para a cana planta e soca, respectivamente. Apresentaram viabilidade econômica, a cana-de-açúcar cultivada em sequeiro e com 60% da ETc, apresentando diferença no custo de produção de 53,94% e do lucro líquido de 52,20%, com retorno financeiro no ano de implantação e com 4 anos e 4 meses, respectivamente.

La biodiversité favorise un grand nombre de fonctions et services écosystémiques des écosystèmes forestiers tels que la production de bois ou la résistance aux attaques d’insectes et aux maladies. Cependant l’impact de la diversité sur l’acquisition et l’utilisation de l’eau et du carbone reste largement méconnu dans ces écosystèmes. De plus, dans le contexte actuel de changement climatique, l’influence de la diversité sur la réponse des écosystèmes forestiers à des événements climatiques extrêmes tels que la sécheresse reste à étudier. L’objectif de ce travail est donc de déterminer l’impact de la diversité en espèces d’arbre sur d’importantes fonctions du cycle de l’eau et du carbone telles que la transpiration, la composition isotopique du carbone ou la profondeur d’extraction de l’eau à l’échelle de l’arbre et de l’écosystème sous des conditions contrastées dedisponibilité en eau du sol. Ce travail a été réalisé dans le cadre du projet FunDivEUROPE sur un réseau de parcelles forestières ainsi que dans des plantations expérimentales le long d’un gradient Nord-Sud en Europe afin de couvrir une importante gamme de conditions climatiques. Nos travaux ont montré une importante variabilité de la réponse à la diversité à l’échelle de l’arbre et de l’écosystème en termes de relations hydriques et carbonées à travers l’Europe. La diversité en espèces ne semble pas influencer les relations hydriques et carbonées des espèces et des écosystèmes forestiers dans des conditions non limitantes de disponibilité en eau. Cependant, un fort effet de la diversité a été observé en conditions de sécheresse pour certains types forestiers. A partir de ces résultats, je discute des mécanismes d’interaction entre espèces qui peuvent expliquer les effets observés. Nos données ont montré que l’influence de la diversité en espèces est fortement dépendante du contexte et peut êtremodifiée par les conditions environnementales locales et les conditions climatiques. En terme de gestion forestière, je suggère que pour certaines régions en Europe, promouvoir la diversité en espèces ainsi que contrôler la densité des parcelles doit être recommandé afin d’adapter les écosystèmes forestiers aux futures conditions climatiques / Biodiversity is known to support and boost a wide range of forest ecosystem functions and services like productivity and resistance against insect pests and diseases. However, whether tree species diversity also promotes water and carbon acquisition and use in forest ecosystems is still unclear. Furthermore, in the current context of global warming, information on how tree species diversity can influence the response of forest ecosystems to extreme climatic events such as drought are urgently needed. In this framework, the objective of my PhD thesis was to determine how tree species diversity influences important functions of the water and carbon cycle including transpiration, carbon isotope composition and water extraction depth at the tree- and ecosystem-Scale under contrasting soil water conditions. My work was conducted within the FunDivEUROPE project in a network of permanent forest stands and tree plantations across a North-South gradient in Europecovering a wide range of climatic conditions. I found considerable variability among species or forest types in the response of transpiration and carbon isotope composition at the tree- and ecosystem-Scale across Europe. Species diversity did not affect the water and carbon relations of tree species and forest ecosystems under non-Limiting soil water conditions. However, a strong effect of species diversity was observed under drought conditions in some forest types. Based on these data, I discuss the potential mechanisms of species interactions that may explain the observed patterns. I also point out that the influence of species diversity is highly context-Dependent, and changes with local environmental and climatic conditions. In terms of forest management applications, I suggest that, at least in some regions, controlling for tree species diversity along with stand density and total basal area could be recommended to help forests adapt to drier conditions

A governança da água apresenta-se como caminho e paradigma na implementação de uma gestão descentralizada e participativa capaz de permear, com estes princípios, todas as instâncias e instrumentos de gestão. A outorga de direito de uso da água é um dos instrumentos previstos nas legislações federal e estadual (SP) cuja utilização permite controlar o acesso quantitativo e qualitativo a estes recursos. Concedida em consonância com as normas, critérios e diretrizes previamente estabelecidas, é a outorga que concede o direito e autoriza o uso privativo de bem público de uso comum do povo por particular, isto é, o uso da água. É também por meio da outorga que são disciplinados os usos considerados prioritários, insignificantes e orientada a alocação da água nas Bacias Hidrográficas. Especificamente quanto às diretrizes que orientam sua alocação, destaca-se a função do Plano de Bacia. Elaborado no âmbito dos Comitês de Bacias Hidrográficas, cabe ao Plano de Bacia, também chamado de Plano de Recursos Hídricos, oferecer as bases para a alocação da água, por meio das outorgas de direito, determinando seu parâmetro e comportamento nos diferentes regimes hídricos, incluindo os de agravamento de escassez hídrica. Diante deste contexto, o presente trabalho aprofunda as discussões e busca avaliar as restrições impostas às outorgas na Bacia Hidrográfica dos rios Piracicaba, Capivari e Jundiaí (PCJ) entre 2014 e 2017, seus fundamentos e observância aos princípios da descentralização e da participação. A partir dos elementos que compõe o conceito de governança da água e da contextualização da água no ordenamento jurídico brasileiro, o trabalho analisa, com apoio nas normas vigentes, os elementos e características da outorga de direito de uso da água, bem como sua relação com o Plano e com o Comitê de Bacia. Em seguida, analisa-se o Plano vigente durante o período escolhido em três diferentes dimensões: quanto à composição do Comitê e das Câmaras Técnicas atuantes em sua elaboração, quanto ao processo de contratação, elaboração e aprovação e quanto ao seu conteúdo, especialmente na constatação de diretrizes aplicáveis às restrições incidentes sobre as outorgas em períodos de agravamento da escassez. São também analisadas as atuações da Agência Nacional de Águas (ANA) e do Departamento de Águas e Energia Elétrica do Estado de São Paulo (DAEE) e as restrições estabelecidas, por meio de atos normativos, e que incidiram sobre outorgas entre os anos de 2014 e 2017. Constata-se, ao fim, o pequeno envolvimento do Comitê na elaboração do Plano de Bacia vigente à época, a lacuna de seu conteúdo no tratamento de situações críticas e emergenciais e a centralização da concepção das medidas de restrição das outorgas de direitos de uso na bacia dos rios PCJ, restrições estas que se mostram incompatíveis com as diretrizes do quadro normativo vigente. / Water governance presents itself as a path and paradigm in the implementation of a decentralized and participative management that is capable to permeate, with these principles, all the instances and instruments. The water grant is one of the instruments provided by the federal and state (SP) laws, which allows to control quantitative and qualitatively the access to these resources. When granted in accordance to the regulatory standards, criteria and guidelines previously established, the water grant guarantees the right and authorizes the private use of a commonweal by particular, that is, the use of water. It is also through the water grant that uses are disciplined according to its priority, meaningless and the water allocation is oriented in the River Basins. Specifically regarding the guidelines that lead its allocation, the function of the Basin Plan is highlighted. Being repared in the scope of the River Basins Committees, it is the responsibility of the Basin Plan, also called as Water Resources Plan, to provide the basis for the water allocation, by the water grant, defining its parameters and behavior in the different water polities, including those of water shortage aggravation. In the view of this context, the current research deepens the discussions and seeks to evaluate the restrictions imposed to the water grant on Piracicaba, Capivari and Jundiaí (PCJ) the River Basin between 2014 and 2017, its foundations and compliance with the principles of decentralization and establishment. Based on the elements that make up the concept of water governance and the contextualization of water in the Brazilian legal system, the research analyzes, with the support of current regulatory standards, the elements and characteristics of water grant, as well as its relation with the Plan and Basin Committee. Afterwards, the current Plan is analyzed according to the selected period in three different dimensions: in regards of composition of the Committee and the Technical Chambers involved in its elaboration, contracting process, elaboration and approval and its content, especially in the verification of the applicable guidelines to restrictions on concessions of water grant in times of shortages aggravation. It is also analyzed the actions taken by the National Water Agency (ANA) and the Department of Water and Electric Energy of the State of São Paulo (DAEE) and the restrictions established, through normative acts, and that affects the water grants between 2014 and 2017. Finally, it is possible to verify the little involvement of the Committee in the Basin Plan elaboration in force at the time, lacks of its content in the treatment of critical and emergency situations, and the centralization in the conception of the restricting measures of the water grant in the PCJ river basins, restrictions that are shown incompatible with the guidelines of the current regulatory framework.

The City of Dallas Environmental Education Initiative (EEI) is a hands-on, inquiry-based, K-12 water conservation education program that teaches students concepts about water and specific water conservation behaviors. Few descriptions and evaluations, especially quantitative in nature, of water conservation education programs have previously been conducted in the literature. This research measured the quantitative effects and impacts of the education program on water use in single-family homes in Dallas, Texas. A total of 2,122 students in 104 classrooms at three schools in the Dallas Independent School District received hands-on, inquiry-based water conservation education lessons and the average monthly water use (in gallons) in single-family homes was analyzed to measure whether or not there was a change in water use. The results showed that over a period of one calendar year the water use in the single-family homes within each school zone and throughout the entire research area in this study experienced a statistically significant decrease in water use of approximately 501 gallons per home per month (independent, t-test, p>0.001). Data from this research suggests that EEI is playing a role in decreasing the amount of water used for residential purposes. Additionally, this research demonstrates the use of a quantitative tool by which a water conservation education program’s effect on behavior change can be measured. This research shows great promise for reducing use and increasing the conservation of our world’s most precious resource.

As average global temperatures rise, cool-season C3 turfgrasses, such as the most commonly grown Kentucky bluegrass (Poa pratensis L.; KBG), struggle to tolerate extreme summer heat and increase their water consumption. Hybrid Bermudagrass (Cynodon dactylon [L.] Pers. × Cynodon transvaalensis Burtt Davy; HBG) is a warm-season C4 grass that may be increasingly suited for northern ecosystems traditionally classified as transition or cool-season climate zones. Glasshouse and field studies were conducted to compare HBG and KBG water use. The objective of the glasshouse study was to evaluate plant health and growth for two HBG cultivars (‘DT-1’ and ‘NorthBridge’) compared to a blend of KBG cultivars in all combinations of deficit, moderate, and high irrigation at optimum or short mowing height. The study was conducted in a glasshouse at Provo, UT, USA from 2020-2021. Grass was grown in pots arranged in a randomized complete block, full factorial design, with four replications of each treatment. The moderate KBG was also significantly different from both high and deficit for verdure and for the last half of NDVI. The objective of the field study was to evaluate two HBG cultivars (‘Tahoma 31’ and ‘Latitude 36’) compared to a blend of KBG cultivars for water loss and canopy health, temperature, and growth when subjected to deficit, moderate, and high irrigation. The study was arranged in a randomized complete block, full factorial design with three replications per treatment, and was conducted at Provo, UT, USA throughout the summer of 2021. In both the glasshouse and field trials, the deficit irrigated KBG consistently scored lower for NDVI and visual turf quality than all other treatments, including moderate and high KBG. This same trend was seen in the field study for percent cover. Although not observed in the glasshouse trial, it was observed in the field trial that the different irrigation levels of HBG resulted in no significant differences for any measurements but the HBG regularly scored better than KBG. The canopy temperatures of deficit irrigated KBG were also higher than all other treatments on most dates. The shoot mass, thatch mass, and total biomass of KBG were significantly less than either HBG cultivar. In the glasshouse trial it was observed that all deficit grasses were significantly lower than the other irrigation treatments and HBG had significantly deeper roots than KBG, although these results were not seen in the field trial. The data suggest that irrigation needs will be less for HBG than KBG and that HBG could provide a water-saving turfgrass alternative to KBG in semi-arid, cool-season regions with increasing water scarcity.