O presente trabalho tem por objetivo caracterizar os abatedouros de frango da microrregião de Pato Branco, analisando as interfaces de suas características organizacionais, de inovação tecnológica e uso da água, considerando o modelo de gestão ambiental de Produção Mais Limpa. Para seu desenvolvimento, adotou-se a metodologia de análise multicasos, com abordagem predominantemente qualitativa. Como instrumentos de coleta de dados em campo foram utilizados questionários semiestruturados aplicados na forma de entrevista, compostos por questões abertas e fechadas, além de observações. Os questionários foram formulados a partir da adaptação de perguntas do Questionário de Pesquisa e Inovação – PINTEC 2011. Os resultados indicam que o setor é composto por empresas de médio-grande porte, de formação Ltda, S/A e Cooperativa. Tais empresas processam em média 12.051 toneladas de carne de frango ao mês na forma de produto in natura (carcaça inteira) e de valor agregado (cortes, miúdos e embutidos) destinando 61% de sua produção para o mercado interno e 39% para o externo. Analisando o período de 2010 a 2012 foi observado que duas das três empresas apresentaram atividades de inovação tecnológica em produtos e processos (TPP), sendo que uma focou mais em produtos e a outra mais em processos, apresentando características de inovação tanto incrementais como radicais nas atividades desenvolvidas. Analisando as inovações TPP, constata-se que estão diretamente relacionadas ao uso da água e a minimização e reciclagem de resíduos, sendo elas inovações no aproveitamento da gordura abdominal; à aquisição de máquinas e equipamentos para a automatização e/ou ampliação dos processos de automatização; a modificações no layout para melhor captação de resíduos; a práticas de controle da água (travas e estranguladores de registro e hidrômetro; bicos aspersores; reuso da água); e ao aproveitamento total dos resíduos orgânicos resultantes do processo produtivo. Essas ações tiveram como retorno para as organizações: a minimização de efluente gerado; a redução no uso da água no processo produtivo; e uma maior margem de lucro na reciclagem dos resíduos para fabricação de farinha e óleo do que com sua revenda a terceiros. Pode-se concluir que os abatedouros de frango da microrregião de Pato Branco conseguiram incorporar as premissas do modelo de Produção Mais Limpa às práticas de uso da água e de inovação tecnológica, conciliando ganhos econômicos com benefícios ambientais. / This study aims to characterize the chicken slaughterhouses of Pato Branco microregion, analyzing the interfaces of their organizational characteristics, technological innovation and use of water, considering the environmental model of Cleaner Production. For its development, it was adopted the methodology of multicase analysis with a predominantly qualitative approach. As tools for collecting data in the field, semi structured questionnaires consisting of open and closed questions were applied by interview, as well as observations. The questionnaires were formulated based on the adaptation of questions from the Research and Innovation Questionnaire - PINTEC 2011. The results indicate that the sector is composed of medium- large - sized companies, formed by limited-liability company, corporation and a cooperative. Such companies processed on average 12,051 tonnes of chicken per month, being processed in natura meat (whole carcass) and value added products (cuts, offals and processed mixed meat) allocating 61 % of its production to domestic market and 39 % for foreign market. Looking at the period from 2010 to 2012 was observed that two of the three companies showed technological innovation activities in product and process (TPP), one focusing on products while the other focusing on processes, presenting both incremental and radical features of innovation to the performed activities. Analyzing the TPP innovations, some are directly related to water use and minimizing and recycling waste, being these innovations in the use of abdominal fat, the acquisition of machinery and equipment for automation and/or expansion of automation processes, changes in layout for better capturing of waste; practices in water control (locks and registration chokes and hydrometer; sprinkle nozzles, water reuse) and the total use of organic waste resulting from the production process. These actions had as a return for organizations: minimization of generated effluent, reduction in water use in the production process; higher profit margin in the recycling of waste for the manufacture of flour and oil to resale to third parties. It can be concluded that the chicken slaughterhouses of Pato Branco microregion succeeded to incorporate the assumptions of the Cleaner Production model to practices of water use and technological innovation concealing economic gains to environmental benefits.

abstract: The dynamics of urban water use are characterized by spatial and temporal variability that is influenced by associated factors at different scales. Thus it is important to capture the relationship between urban water use and its determinants in a spatio-temporal framework in order to enhance understanding and management of urban water demand. This dissertation aims to contribute to understanding the spatio-temporal relationships between single-family residential (SFR) water use and its determinants in a desert city. The dissertation has three distinct papers to support this goal. In the first paper, I demonstrate that aggregated scale data can be reliably used to study the relationship between SFR water use and its determinants without leading to significant ecological fallacy. The usability of aggregated scale data facilitates scientific inquiry about SFR water use with more available aggregated scale data. The second paper advances understanding of the relationship between SFR water use and its associated factors by accounting for the spatial and temporal dependence in a panel data setting. The third paper of this dissertation studies the historical contingency, spatial heterogeneity, and spatial connectivity in the relationship of SFR water use and its determinants by comparing three different regression models. This dissertation demonstrates the importance and necessity of incorporating spatio-temporal components, such as scale, dependence, and heterogeneity, into SFR water use research. Spatial statistical models should be used to understand the effects of associated factors on water use and test the effectiveness of certain management policies since spatial effects probably will significantly influence the estimates if only non-spatial statistical models are used. Urban water demand management should pay attention to the spatial heterogeneity in predicting the future water demand to achieve more accurate estimates, and spatial statistical models provide a promising method to do this job. / Dissertation/Thesis / Ph.D. Sustainability 2013

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-10-06T14:05:58Z No. of bitstreams: 1 Gian Carlo Carvalho.pdf: 3117159 bytes, checksum: 05e217ee9f166bd343c80310a85d6838 (MD5) / Made available in DSpace on 2016-10-06T14:05:58Z (GMT). No. of bitstreams: 1 Gian Carlo Carvalho.pdf: 3117159 bytes, checksum: 05e217ee9f166bd343c80310a85d6838 (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The effective use of water has been the key component for food production and for the high quality of products in the arid and semiarid regions due to the increasing lack of available water resources. The water deficit may yield several crop physiological responses from which stomatal closure and transpiration reduction stand out. The partial root drying technique has been an alternative for gain in yield an increase of water use efficiency. The objectives of the work were by means of strategies for use of PRD, to select an irrigation schedule that allow to reduce water from irrigation without significant loss of fruit yield. Yield and water use efficiency were evaluated as well root system distribution, soil water distribution and water extraction by plants. The PRD technique was applied in an experiment inside an area of Ceral farm from Organic Bioenergy Company at chapada Diamantina Lençois, county, Bahia State with the varieties of Bermuda Cherry: Junco and Rubra using 4 x 2m spacing irrigated by autocompensating drippers of 4 L h-1 flow rate. The experiment followed a random block design with two varieties, five irrigation schedules and three replications totalizing 30 experimental plots. The irrigation schedules were based upon the percent of reduction of calculated water depth, that was fixed in 50% and on the time for switching irrigation side of the plant (7, 14, and 21 days), where: (PRD 7 – reduction of 50% ETc switching plant side every 7 days, PRD 14 – reduction of 50% ETc switching plant side every 14 days, PRD 21 – reduction of 50% ETc switching plant side every 21 days, IF – reduction of 50% ETc keeping the irrigation just at one side of the plant during the whole cycle e IP – full irrigation, i.e., 100% ETc). The largest productivities were registered when irrigation has supplied 100%ETc and for PRD with reduction 50% ETc switching plant sides every 7 and 14 days. The water use efficiency was larger for irrigation schedule with PRD by switching irrigated plant side every 7 days whose value was twice the one for treatment with 100% ETc. Soil water distribution is similar for all schedules six hours after irrigation. Soil water available to plants did not reduce so drastically at the non irrigated side for PRD with change in irrigation side every 7 days compared to others treatments. This resulted in larger yields for this treatment. The root system showed larger development at shallower soil layers. The regions of larger water extraction are influenced by amount of available water and by root length density. / A utilização eficaz da água tem se tornado uma componente chave na produção de alimentos e da alta qualidade dos produtos nas regiões áridas e semiáridas, devido à crescente falta de recursos hídricos disponíveis. O déficit hídrico pode provocar diversas respostas fisiológicas nas culturas, destacando-se o fechamento dos estômatos e a redução da transpiração. Dentre as técnicas de irrigação que utilizam déficit hídrico, o secamento parcial do sistema radicular (PRD) tem se mostrado uma alternativa para ganhos em produtividade e aumento da eficiência do uso de água. Os objetivos do trabalho foram, através das estratégias de uso do PRD, selecionar um manejo de irrigação que permita reduzir o consumo de água sem perdas significativas na produção dos frutos. Para isso, avaliou-se a produtividade, eficiência do uso de água, distribuição do sistema radicular, distribuição de água no solo e extração pelas plantas. A técnica do PRD foi aplicada em um experimento em uma área de aceroleira, na fazenda Ceral, pertencente à empresa Bioenergia Orgânicos, localizada na chapada Diamantina, Município de Lençóis – BA. As variedades utilizadas foram Junco e Rubra, com espaçamento 4 x 2 m, irrigadas por gotejadores autocompensantes com vazão de 4 L h-1. O experimento seguiu delineamento em blocos casualizados, com cinco manejos de irrigação, três repetições e duas variedades, totalizando 30 parcelas experimentais. Os manejos foram baseados na percentagem de redução da lâmina calculada de irrigação, fixada em 50%, e no tempo de alteração da irrigação de cada lado da planta (7, 14 e 21 dias), sendo, PRD 7 – redução de 50% da ETc, alternando a cada 7 dias, PRD 14 – redução de 50% da ETc, alternando a cada 14 dias, PRD 21 – redução de 50% da ETc, alternando a cada 21 dias, IF – irrigação fixa em um lado da planta com redução de 50% da ETc em todo o ciclo e IP – irrigação plena, ou seja,100% da ETc em ambos os lados da planta. As maiores produtividades foram registradas para os manejos de PRD com alternância de 7 e 14 dias juntamente com o manejo de irrigação plena. A eficiência do uso de água foi maior para o manejo de irrigação PRD, com alternância de 7 dias, superior ao dobro do tratamento com 100% da ETc. O comportamento da distribuição de água no perfil do solo seis horas após a irrigação, no lado irrigado, é semelhante para todos os manejos. No lado submetido à secamento, no manejo PRD, com alternância de 7 dias, a quantidade de água disponível para as plantas não diminuiu tão drasticamente quanto nos demais manejos o que resultou na maior produtividade absoluta destas. O sistema radicular apresentou maior desenvolvimento nas camadas mais superficiais do solo. Quanto às regiões de maior extração de água no solo, estas sofrem influência em relação à quantidade de água disponível e densidade de comprimento de raízes.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-10-18T11:57:42Z No. of bitstreams: 1 Ligia Borges Marinho.pdf: 6523929 bytes, checksum: 33ade733585d1cbbe9567d615e5974e4 (MD5) / Made available in DSpace on 2016-10-18T11:57:42Z (GMT). No. of bitstreams: 1 Ligia Borges Marinho.pdf: 6523929 bytes, checksum: 33ade733585d1cbbe9567d615e5974e4 (MD5) Previous issue date: 2008-01-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The viticulture in the São Francisco Valley region has been growing at a significant pace in this decade, being responsible for about 90% of table grape export of the country in 2004. Irrigation practices have been adjusted in order to meet the need to culture water e to reduce irrigation water costs. The aim of this work was to evaluate the Superior seedless table grape when subjected to controlled water in the maturation stage of the grape, the water use efficiency and post-harvest performance, in the submédio region of the São Francisco River, in Casa Nova, Bahia. The statistical design was in random blocks, in a factorial scheme of 3x3 with four replicates, with timing of irrigation cut-off of irrigation depths (at 21,13, and 5 days before harvest) and three liquid blades of irrigation applied ( 100% ETc, 50% ETc and 0% ETc) and an additional treatment which represented the grower´s practice. The vines used between 335 mm and 390 mm of water in the production cycle, with a water economy of 48.5%and 94.5% for the deficit treatments in relation to the treatment that received the highest amount of water during the maturation stage of the grape. The soil water matric potential varied from -4 kPa beforematuration up to a maximum -73.6 kPa during treatment application. Water use efficiency varied between 6.42 kg.m-3 to 9.32 kg.m-3 of water , and the pre-dawn leaf water potential ranged from -0.1 MPa to -0.25 MPa and mid-day leaf water potential between -1.0 MPa and -1.8 MPa. The average grape diameter, bunch weight and yield were not significantly affected at the Duncan´s 5% level, however the number of bunches varied between 29 to 38, with weights of from 610 g to 690 g. The firmness was not influenced by the regulated deficits applied in the post-harvest conservation. The values of SS, AT and the SS/TA relationship at harvest were all equal or higher than export standards, ranging from 15.9 ºBrix to 17.2 ºBrix, 0.43 g of tartaric acid/100ml of juice to 0.467 g of tartaric acid/100ml of juice and SS/TA relationships between 35.66 and 39.72. In the post-harvest conservation period the values of SS varied from 15.81 ºBrix to 16.68 ºBrix, the TA varied from 0.42 g of tartaric acid/100ml of juice to 0.46 g of tartaric acid/100ml of juice, whereas the SS/TA varied from 37.76 to 36.35 at 28 days from cold chamber storage. / A viticultura na região do Vale do São Francisco vem apresentando um crescimento bastante significativo nesta década, tendo sido, responsável por cerca de 90% das exportações de uva de mesa do país, em 2004. As práticas de irrigação têm sido ajustadas com o fim de atender a demanda de água da cultura e reduzir o consumo de água na irrigação. O objetivo do trabalho foi avaliar a videira cv. Superior Seedless quando submetida a déficits hídricos controlados de água na fase da maturação da uva, eficiência de uso de água e conservação pós-colheita, na Região do Submédio São Francisco, Casa Nova-BA. Utilizou-se o delineamento estatístico em bloco ao acaso, em esquema fatorial 3x3 com quatro repetições, sendo três épocas de corte na aplicação das lâminas (aos 21, 13 e 5 dias antes da colheita) e três lâminas líquidas de irrigação (100% , 50% e 0%) e um tratamento adicional, o qual correspondeu ao manejo adotado pelo produtor. O consumo hídrico da videira variou entre 335 mm e 390 mm no ciclo de produção, que resultou em uma economia de água que variou de 48,5% a 94,5% para os tratamentos deficitários em relação ao tratamento com maior suprimento de água, durante a fase de maturação da uva. Os potenciais matriciais da água no solo variaram em média de -4 kPaantes da maturação até um máximo de -73,6 kPa, durante a aplicação dos tratamentos. A eficiência do uso de água variou de 6,42 kg.m-3 a 9,32 kg.m-3 de água. O potencial hídrico foliar antes do alvorecer variou entre -0,1 MPa e -0,25 MPa e ao meio dia entre -1,0 MPa a -1,80 MPa. A média de diâmetro de bagas de uva e peso de cacho não foram afetados significativamente, pelo teste Duncan a 5%, no entanto o número de cachos variou de 29 a 38, com peso de 610 g a 690 g. A firmeza não sofreu influência do déficit hídrico regulado, após armazenamento em câmara fria. Os valores dos atributos: sólidos solúveis (SS), acidez total (AT) e a relação de SS/AT, por ocasião da colheita, formam iguais ou superiores aos padrões exigidos para exportação, variando de 15,9 ºBrix a 17,20 ºBrix, 0,43 g de ácido tartárico/100 ml de suco a 0,467 g de ácido tartárico/100 ml de suco e de 35,66 a 39,72, respectivamente. Na conservação pós-colheita obteve-se valores de SS variando de 15,81 ºBrix a 16,68 ºBrix; AT passando de 0,42 g de ácido tartárico/100 ml de suco para 0,46 g de ácido tartárico/100 ml de suco e a relação SS/AT decrescendo de 37,76 para 36,35, após 28 dias armazenamento, em câmara fria.

Made available in DSpace on 2016-12-23T14:37:44Z (GMT). No. of bitstreams: 1 Joao_Vitor_Toledo.pdf: 607615 bytes, checksum: dab692118bf86f9eb81d6ef843ae5306 (MD5) Previous issue date: 2012-01-24 / O eucalipto é a espécie florestal de rápido crescimento mais utilizada no Brasil, sendo o seu cultivo um dos mais avançados, produtivos e competitivos do mundo. O estresse induz mudanças e respostas em todos os níveis funcionais do organismo vegetal. O déficit hídrico, portanto, causa alterações no comportamento e desenvolvimento vegetal, e dependendo do genótipo, este pode ser mais ou menos tolerante a condições adversas do clima. Objetivou-se com este trabalho avaliar a influência de diferentes regimes hídricos em relação à água disponível no solo, sobre o crescimento e o desenvolvimento, durante 60 dias da fase de estabelecimento, de três clones de eucalipto, do híbrido Eucalyptus urophylla x Eucalyptus grandis. Este estudo foi desenvolvido em casa de vegetação instalada na área experimental do Centro de Ciências Agrárias da Universidade Federal do Espírito Santo, localizada no município de Alegre- ES. O experimento foi montado no esquema Fatorial 3x3 em delineamento experimental em blocos casualizados. Os tratamentos constituíram-se da interação de três níveis de água disponível no solo (50%, 30% e 10%), com o fator clones (Clone 1, Clone 2 e Clone 3), com quatro repetições. As mudas foram cultivadas em vasos com volume de 30 dm³. O controle dos níveis de depleção foi realizado através do monitoramento da massa de cada vaso, com o auxílio de uma balança, sendo a umidade elevada até a capacidade de campo até obter a umidade referente ao tratamento. Foram avaliados os valores de altura, diâmetro, número de folhas, área foliar, matéria seca total, matéria seca de folhas, matéria seca de raiz, matéria seca de haste e ramos, volume de raiz, lâmina total consumida e eficiência do uso da água. Os dados foram submetidos à análise de variância, e quando significativas, as médias foram comparadas pelo teste de Tukey ao nível de 5% de probabilidade. As avaliações executadas indicam que os níveis de disponibilidade de água abaixo de 50% da água disponível prejudicam o crescimento de todos os clones. A redução média da matéria seca total dos três clones estudados é de 21% e 40% para os níveis de 30% e 10%, respectivamente, em relação à produção de biomassa das plantas submetidas a 50% da água disponível. O Clone 2 apresenta médias estatisticamente superiores aos demais nos parâmetros matéria seca, número de folhas e eficiência do uso da água, se mostrando, portanto, superior sob condição de restrição hídrica. Portanto, o Clone 2 é mais indicado para implantação em regiões tanto com maior como menor disponibilidade hídrica / Eucalyptus is a fast growing tree species most used in Brazil, and its cultivation is of the most more advanced, productive and competitive in the world. Stress induces changes and responses in all functional levels the plant organism. The water deficit therefore causes changes in behavior and plant development, and depending on the genotype, it may be more or less tolerant to adverse weather conditions. The objective of this work was evaluate the influence of different regimes water through the water availability in the soil on the growth and development during 60 days of phase establishment of three eucalyptus clones, the hybrid Eucalyptus grandis x Eucalyptus urophylla. This study was conducted in a greenhouse attached to the experimental area of the Centro de Ciências Agrárias of Universidade Federal of Espírito Santo, located in municipality of Alegre-ES. The experiment was arranged with a 3x3 factorial arrangement in experimental randomized blocks design. The treatments consisted of interaction of three levels of available soil water (50%, 30% and 10%), with the clones factor (Clone 1, Clone 2 and Clone 3) with four replications. The seedlings were grown in vessels with a volume of 30 dm³. The control of the levels of depletion was performed by monitoring the mass of each vessel with the aid of a scale, being the humidity high up to capacity field until it obtains the moisture related to the treatment. It was evaluated values of height, diameter, leaf number, area leaf dry weight, dry leaves, root dry matter, dry stem and branches, root volume, depth and efficiency of the total consumed use of water. Data were analyzed by variance, and when significant, means were compared by Tukey test at level 5% probability. The evaluations performed indicate that the water availability levels below 50% of water available affect the growth of all clones. The average reduction of total dry matter of the three clones studied is 21% and 40% at levels of 30% and 10% respectively, for the production of biomass from plants subjected to 50% of available water. The Clone 2 presents averages statistically superior to the other in dry parameters, number of leaves and efficiency of water use, proving therefore more subject to water restriction. Therefore, the Clone 2 is more suitable for deployment in both regions more and less water availability

Orientador: Lindon Fonseca Matias / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-23T01:50:51Z (GMT). No. of bitstreams: 1 Fonseca_MarceloFernando_D.pdf: 21621701 bytes, checksum: 349eff0b0a072e1431daf4956ae32f38 (MD5) Previous issue date: 2013 / Resumo: A pesquisa aqui empreendida consistiu na elaboração de um estudo destinado a fornecer indicativos para a tomada de decisão no âmbito do processo de planejamento e de gestão territorial do entorno do reservatório de Salto Grande, localizado nos municípios de Americana, Nova Odessa e Paulínia, Estado de São Paulo, adotando-se como prerrogativa a assertiva de usos múltiplos da água. Como subsídio às análises, utilizaram-se procedimentos e técnicas de geoprocessamento, concomitantes à metodologia de análise geográfica, para a constituição de uma ampla base de dados georreferenciados. O planejamento e a gestão de áreas urbanas, conduzidos de forma desarticulada e equivocada, têm contribuído decisivamente para o aprofundamento das contradições e desigualdades socioespaciais, dando origem a conflitos que devem ser objeto de reflexão, em especial, das ciências humanas e, sem dúvida, da Geografia. Constata-se a imersão da área de estudo em processos correntes de urbanização, acompanhados de impactos socioambientais diretamente relacionados, com notável prejuízo à qualidade da água e sua área de entorno. Desta forma, avaliando-se suas especificidades e potencialidades, sob um enfoque geográfico, argumenta-se no sentido da predição de um novo cenário e proposituras que contemplem os usos múltiplos da água para o reservatório e seu entorno, dando ênfase na importância das relações de todos os agentes sociais direta e indiretamente envolvidos com a problemática socioespacial que ali se desenvolve / Abstract: The research undertaken here is to draw up a study to provide indicators for decision making in the process of territorial planning and management surrounding Salto Grande reservoir, located in the cities of Americana, Nova Odessa and Paulínia, in São Paulo State, adopting as prerogative the statement of multiple uses of water. As support to the analysis, it has used geoprocessing procedures and techniques, concurrently with the geographic analysis methodology for the establishment of a comprehensive georeferenced database. The planning and management of urban areas, conducted in a disjointed and misguided way, have contributed decisively to the deepening of contradictions and socio-spatial inequalities, giving rise to conflicts that must be reflected, in particular, in human sciences, and undoubtedly in geography. It has observed the immersion of the study area in current processes of urbanization, accompanied by environmental impacts directly related with remarkable damage to water quality and its surrounding area. Thus, evaluating their specificities and potentialities, under a geographical focus, it is argued in the sense of predicting a new background and propositions that address the multiple uses of water to the reservoir and its surroundings, emphasizing the importance of all social agents relations directly and indirectly involved with the sociospatial issue which is developed there / Doutorado / Análise Ambiental e Dinâmica Territorial / Doutor em Ciências

To address increasing irrigation water demand consecutive to the increasing population pressure in terms of food demand, there is an imperative of developing relevant mechanisms to regulate irrigation water consumption patterns. A radical shift from uncontrolled flooding irrigation as currently practiced by farmers in Mugerero paddy farming zone towards efficient allocation and use of water resources is important to save water that could be allocated to other water users. This paper surveys current and past views on the way irrigation water is allocated in the irrigation scheme of Mugerero and how farmers are using water for paddy production purpose. The existing irrigation water practices as well as paddy productivity are assessed and the results are expected to be useful for water policy professionals, while addressing the growing water demand. According to the respondents, the causes of low paddy yields are the increasing and uncontrolled extension of paddy farming, non adapted irrigation infrastructure and water pricing systems as well as lack of updated knowledge and technologies on irrigation. These issues faced by the paddy farmers have led to pronounced economic, social and environmental consequences which are manifested in conflicts over irrigation water use, increasing soil salinity and pollution, destruction of infrastructure and above all, low irrigation paddy yields.The identification of the core problem in the irrigation system might be important for water managers as it would provide a starting point to establish comprehensive baseline towards efficient irrigation water allocation and use. This would improve paddy productivity within the formal as well as the growing informal paddy farming referred to “hors- perimeter” in the low land of Imbo region.

Les plantations d’hévéa (Hevea brasiliensis) s’étendent vers des zones non traditionnelles de production en Thaïlande où des conditions plus sèches ont pu conduire à une diminution de la croissance des arbres et de la production de latex. Des paramètres physiologiques utiles pour sélectionner des génotypes adaptés sont nécessaires, comme l’efficience d’utilisation de l’eau (WUE). La discrimination isotopique du carbone est largement utilisée comme proxy pour WUE et peut être aisément utilisée dans des programmes de sélection pour la tolérance à la sécheresse. δ13C des feuilles et les échanges gazeux foliaires ont été mesurés sur de jeunes plants de dix clones d’hévéa cultivés en pot dans une pépinière. La gamme de δ13C des feuilles entre ces dix clones était restreinte et la corrélation entre δ13C et WUEi était significative que sous fort déficit de pression de vapeur saturante, ce qui signifie que la prédiction de WUE par δ13C serait peu précise. Il y avait une large gamme de δ13C entre les génotypes dans une collection de 49 génotypes sauvages d’hévéa cultivés dans le nord-est de la Thaïlande en saison sèche et en saison des pluies. δ13C était relativement stable avec une bonne corrélation entre les saisons. Cette étude montre que la variabilité génétique de δ13C est prometteuse pour des futurs programmes de sélections si une bonne corrélation entre δ13C et WUE peut être établie. L’absence de corrélation entre de δ13C du latex (δ13C-L) et des composés solubles extraits des feuilles (δ13C-S) prélevées sur des arbres saignés et non saignés âgés de 20 ans suggère que photosynthétats récemment produits se mélangent à un stock important d’hydrate de carbone impliqués dans la régénération du latex après la saignée. Donc, δ13C du latex n’est pas un indicateur pertinent de WUE / The rubber (Hevea brasiliensis) plantations extend to non-traditional area in Thailand where dryer conditions has been reported to impair the growth of rubber trees and latex production. Physiological parameters helpful for breeding adapted genotypes are required, such as water use efficiency (WUE). Carbon isotope discrimination is widely used as a proxy for WUE that can easily be used for selection and breeding programs for drought tolerance. Leaf δ13C and leaf gas exchange were measured on young saplings of 10 rubber clones growing in pot in a common garden. The range of leaf δ13C among 10 clones was narrow and the correlation between δ13C and WUEi was significant under high vapour pressure deficit only, which means the prediction of WUE by δ13C would have low precision. There were large δ13C variations among the genotypes at all seasons in a collection of 49 wild genotypes of rubber in Northeastern Thailand. δ13C was rather stable with a good correlation between rainy and dry season. The genetic variability of δ13C is promising for breeding if a good correlation between δ13C of leaf and WUE can be established. The lack of correlation between δ13C of latex (δ13C-L) and of leaf soluble compounds (δ13C-S) collected from tapped and untapped 20 year-old rubber trees suggests that recent photosynthates are mixed in the large pool of stored carbohydrates that are involved in latex regeneration after tapping. Thus δ13C of latex is not a relevant indicator of WUE of rubber trees

Five subtropical perennial grass species, Cenchrus ciliaris, a Cynodon hybrid, Digitaria eriantha subsp. eriantha, Panicum maximum and Pennisetum clandestinum, were subjected to four levels of water availability in a small plot trial under a rainshelter during the summer growing seasons of 1996/97 and 1997/98. This work was carried out on the Hatfield Experimental Farm of the University of Pretoria, Pretoria, South Africa. The average yields for the tufted species (C. ciliaris, D. eriantha and P. maximum) were lower in the 1997/98 than the 1996/97 season. C. ciliaris, however, produced the highest average yields in both seasons. The average yields of the Cynodon hybrid and P. clandestinum (creeping grasses) reacted differently, in that the average yields were higher in the 1997/98 than 1996/97 season. The dry matter yields of all five grass species at slight water deficits, were not significantly different from yields under conditions of no water shortages, when the soil profile was brought to field capacity at the beginning of the growing season. The implication hereof is, that dry matter yields can be maintained, in conditions where slight water deficits occur, if there is some water stored in the soil profile. C. ciliaris, a notable drought tolerant species, produced yields (11.7-20.0 t ha-1) under non-control conditions (W1, W2 and W3) which were comparable to yields obtained from traditionally irrigated grasses such as the Cynodon hybrid (12.0-15.8 t ha-1) and P. clandestinum (5.6-11.8 t ha-1), under control conditions (W4). P.clandestinum, D. eriantha and P. maximum tended to be better adapted to wetter conditions, while the Cynodon hybrid was also able to produce good yields under both water limiting and non-limiting conditions. Water use efficiency, regardless of the grass species, tended to be better under non-control conditions. Grasses were thus able to produce more dry matter per unit of water under conditions where water became scarce. In vitro dry matter digestibility was not negatively affected by water scarcity, while crude protein content more often than not seemed to be better under control conditions. This could be due to the uptake meganism of nutrients, in which water plays a vital role. The number of stoma per unit area was more under control than water limiting conditions. The expression of the different structures on the leaf surfaces, were not altered by the level of water availability. In the absence of water shortages, the growth rates of C. ciliaris, D. eriantha and P.maximum, were almost twice those of the Cynodon hybrid and P. clandestinum, as measured at the end of two growth cycles in an irrigated field trial. In a pot trial, under glasshouse conditions, with C. ciliaris, the Cynodon hybrid and P.clandestinum, both the level of water availability, and the level of nitrogen were varied. Regardless of species and level of nitrogen, water was still used more efficiently under non-control conditions. Higher levels of nitrogen did, however, improve water use efficiency regardless of level of water available. As with higher levels of available water, higher levels of nitrogen also improved yields. In this trial, the Cynodon hybrid and C. ciliarisalso out-yielded P. clandestinum.<,/p> In summary it can be said that C. ciliaris and the Cynodon hybrid are adapted to warm growing conditions in producing high yields regardless of the level of water available. D. eriantha, P. maximum and P. clandestinum would produce better in such growing conditions if water was not as limiting. Regardless of the species, the plants were able to use water more efficiently under non-control conditions, while in Vitro digestibility was not negatively affected by water limiting conditions. Due to the uptake mechanism of nutrients, water limiting conditions may, however, decrease the crude protein content of the grass plants. Higher levels of nitrogen had a positive impact on dry matter yields and water use efficiency. / Thesis (PhD)--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

Please read the abstract in the section 00front of this document / Dissertation (M A (Anthropology))--University of Pretoria, 2007. / Anthropology and Archaeology / unrestricted