Dissertations / Theses on the topic 'Arid zone plants'
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McGee, P. A. "Role of mycorrhizas in the regeneration of arid zone plants /." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phm1448.pdf.
Full textEaston, Lyndlee Carol, and lyndlee easton@flinders edu au. "LIFE HISTORY STRATEGIES OF AUSTRALIAN SPECIES OF THE HALOPHYTE AND ARID ZONE GENUS FRANKENIA L. (FRANKENIACEAE)." Flinders University. Biological Sciences, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20081124.105244.
Full textMagagi, Ramata D. "Étude de synergie optique et micro-onde active : estimation des paramètres de surface en zone semi-aride : cas du Sahel." Toulouse, INPT, 1995. http://www.theses.fr/1995INPT101H.
Full textChaieb, Mohamed. "Influence des réserves hydriques du sol sur le comportement comparé de quelques espèces végétales de la zone aride tunisienne." Montpellier 2, 1989. http://www.theses.fr/1989MON20126.
Full textHeshmatti, Gholam Ali. "Plant and soil indicators for detecting zones around water points in arid perennial chenopod shrublands of South Australia /." Title page, contents and summary only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phh584.pdf.
Full textErrata page is behind title page (p. i). Copies of author's previously published articles inserted. Includes bibliographical references (leaves 121-156).
Monroy, Ata Arcadio. "Installation de plantes pérennes de la zone aride soumises à des contraintes hydriques contrôlées et à des coupes." Montpellier 2, 1989. http://www.theses.fr/1989MON20025.
Full textPierre, Caroline. "Variabilité interannuelle des émissions d'aérosols minéraux en zone semi-aride sahélienne." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00921688.
Full textKarimi, Rachid. "Hydrogéologie et aménagement des eaux en zône aride exemple des plaines de Tagmoute et Tata (sud marocain) /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37614694c.
Full textCosta, Carlos Alexandre Gomes. "Umidade do solo e disponibilidade hídrica na zona das raízes em condições naturais de caatinga preservada." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/18822.
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Regarding ecohydrology, the catchment water is distributed over several important compartments. Many studies in semiarid re gions indicate the surface reservoirs as the main water compartments. However, the watershed has greater scope than the water reservoirs contained therein, and water resources in compartments distributed in the watershed (like in soil) should be analyzed not only with regard to ecological uses, but also as spaces of water availability. Therefore, the object ive of this work was to analyze, based on measurements and modeling, the water dynamics in th e soils of a semi-arid basin in preserved Caatinga, and its impact on water availability. Wit h this in mind, it was measured, among others, the soil moisture, every hour, from 2003 to 2010 (2923 days) in the Aiuaba Experimental Basin (AEB, 12 km ²), fully preserved and with average annual rainfall of 560 mm. Monitoring was carried out through three TDR se nsors, one installed in each of the three soil and vegetation associations (SVA) identified in the basin. The research method considered six main steps: i) assessment of the eff ective root depth of preserved Caatinga ii) calibration of humidity TDR sensors iii) space-time representation of soil moisture in each SVA unit iv) analysis of soil water availability in the root zone, v) parameterization of the WASA-SED hydrological model, and vi) parameterizati on of the DiCaSM hydrological model. The results of this research indicate the importance of addressing the temporal analysis of soil moisture and soil water availability in the root zone to maintain the Caatinga biome. More specifically, it was observed that the effecti ve depth of the root system on AEB ranged between 70 and 80 cm in areas with deep soils, but in areas with shallow soils, it was observed that the effective depth of the roots had adapted to the constraints, having been reduced to less than 40 cm. Furthermore, the season al analysis showed that in the dry season, the roots have lengths up to 11 cm smaller, openin g, therefore, secondary pores that facilitate the penetration of what little rain water falls in the dry months (June-December), as well as in the first rains of the wet season. In the two SVAs whose soils are deep and the vegetation is dense, the soil water is 'not available' (ie below the permanent wilting point - WP) during nearly nine months a year (72% of the time), and on ly during three months of the year (25% of the time) the soil water is available. In the re maining 3% of the year (about 10 days) there is gravitational water in these SVAs. In the SVAs whose soil is shallow and whose vegetation is sparse, the dynamics of soil water are different : the time when there is gravitational water, available and unavailable, is practically the same (four months a year). This is due to, among other things, the low soil moisture at the permanen t wilting point of the Udorthent, and to its limited thickness, generating saturation much more frequently than in others that - unlike this one - have deep drainage. The depletion of soil wat er under conditions of moisture below the wilting point was another important result of this research. In the two associations with deep soils and thick vegetation, it was observed – throu ghout the observation period – continuous fall of moisture level until it approached asymptot ically the residual moisture. More detailed analysis showed that the reduction of soil moisture between the WP and the residual moisture level always followed the exponential decay. It was observed, in the association of shallow soil and sparse vegetation, that the moisture did not fall to below the WP, even subjected to the same rigorous climate of the other associations . Considering: (i) that in such a dry soil, the drainage is unlikely, and (ii) that the associated processes of percolation and evaporation should not be responsible for the removal of soil w ater either (since the phenomenon is not observed in SVAs whose soil is shallow and therefor e warmer) , it is raised the hypothesis that the soil drying under these conditions must be caused by water extraction by vegetation. This would strengthen the argument that the Caating a has adapted to survive under water stress. The hydrological models WASA-SED and DiCaSM failed to adequately represent the temporal dynamics of soil water in the AEB. However , the models did satisfactorily reproduce the retention curves of soil moisture, al lowing the representation of the water availability in the root zone for planning purposes . Finally, we managed to evaluate - quantitatively, spatially and temporally – the soil water availability. This availability is of the same order of magnitude of the availability of an o ptimal surface reservoir. The availability in the soil, in quantitative terms, can be almost five times higher than that of the surface reservoir. However, the security associated with su rface water (90%) is much higher than the water permanence available in the AEB: just 28% in areas with deep soils and 65% in areas with shallow soils.
A água na bacia hidrográfica está distribuída em diversos compartimentos importantes no que se refere à ecohidrologia. Muitos estudos em regiões semiáridas apontam os reservatórios superficiais como principais compartimentos de água. Entretanto, a bacia hidrográfica tem maior abrangência que as bacias hidráulicas nela contida, e os recursos hídricos nos compartimentos distribuídos na bacia hidrográfica (como no solo) devem ser analisados não somente no que se refere aos usos ecológicos, mas também como espaço de disponibilidade hídrica. Portanto, o objetivo do trabalho foi analisar, com base em medidas e modelagem, a dinâmica da água nos solos de uma bacia semiárida de Caatinga preservada e seu impacto sobre a disponibilidade hídrica. Para isso foi medida, entre outros, a umidade do solo a cada hora, de 2003 a 2010 (2923 dias) na Bacia Experimental de Aiuaba (BEA, 12 km²), totalmente preservada e com precipitação média anual de 560 mm. O monitoramento foi realizado através de três sensores TDR, um instalado em cada uma das três associações entre solo e vegetação (SVA) identificadas na bacia. O método de investigação considerou seis etapas principais: i) determinação da profundidade efetiva das raízes da Caatinga preservada; ii) calibração dos sensores de umidade tipo TDR; iii) representação espaço-temporal da umidade do solo em cada unidade de SVA; iv) análise da disponibilidade hídrica do solo na zona das raízes; v) parametrização do modelo hidrológico WASA-SED; e vi) parametrização do modelo hidrológico DiCaSM. Os resultados obtidos nesta pesquisa indicam a importância da abordagem da análise temporal da umidade do solo e da disponibilidade hídrica do solo na zona das raízes para a manutenção do bioma Caatinga. Mais especificamente, foi observado que a profundidade efetiva do sistema radicular na BEA oscilou entre 70 e 80 cm nas regiões com solos profundos, porém, em regiões com solos rasos, observou-se que a profundidade efetiva das raízes adaptou-se às restrições, ficando reduzida a menos de 40 cm. Além disso, a análise sazonal demonstrou que, na estação de estio, as raízes têm comprimentos até 11 cm menores, abrindo, portanto, poros secundários que facilitarão a penetração da água nas eventuais chuvas dos meses secos (junho a dezembro), assim como nas primeiras chuvas da estação úmida. Nas duas SVAs cujos solos são profundos e cuja vegetação é densa, a água no solo encontra-se ‘não-disponível’ (isto é, abaixo do ponto de murcha permanente – WP) em quase nove meses ao ano (72% do tempo); e somente durante três meses ao ano (25%) a água no solo encontra-se disponível. Nos 3% restantes do ano (cerca de 10 dias) há água gravitacional nessas SVAs. Na SVA cujo solo é raso e cuja vegetação é esparsa, a dinâmica da água no solo é diferente: o tempo em que há água gravitacional, disponível e não disponível é praticamente o mesmo (quatro meses ao ano). Isso se deve, entre outros, à baixa umidade do solo no ponto de murcha permanente do neossolo litólico; e à sua restrita espessura, gerando saturação muito mais frequentemente que nos demais solos que – ao contrário deste – dispõem de drenagem profunda. A depleção da água no solo sob condições de umidade abaixo do ponto de murcha foi outro resultado importante desta pesquisa. Nas duas associações com solos profundos e vegetação densa, observou-se – ao longo de todo o período investigado – decaimento contínuo da umidade até que a mesma se aproximasse assintoticamente da umidade residual. Análise mais detalhada demonstrou que a redução da umidade do solo entre o WP e a umidade residual sempre obedecia ao decaimento exponencial. Na associação com solo raso e vegetação esparsa observou-se que a umidade não caía para valores inferiores ao WP, mesmo sujeita ao mesmo rigor climático das demais associações. Considerando-se: (i) que em solo tão seco, a drenagem é improvável; e (ii) que os processos associados de percolação e evaporação tampouco devam ser os responsáveis pela retirada de água do solo (posto que o fenômeno não se observa na SVA cujo solo é raso e, portanto, mais quente); levanta-se a hipótese que o secamento do solo nessas condições deva ser causado por extração de água pela vegetação. Isso reforçaria a tese de que a Caatinga dispõe de adaptação para sobreviver mesmo em condições de estresse hídrico. Os modelos hidrológicos WASA-SED e DiCaSM não conseguiram representar adequadamente a dinâmica temporal da água nos solos da BEA. No entanto, os modelos reproduziram satisfatoriamente as curvas de permanência da umidade dos solos, permitindo representar a disponibilidade hídrica na zona das raízes para fins de planejamento. Por fim, logrou-se avaliar – quantitativa, espacial e temporalmente – a disponibilidade hídrica do solo. Esta é da mesma ordem de grandeza da disponibilidade de um reservatório superficial ótimo. Em termos quantitativos, a disponibilidade no solo chega a ser quase cinco vezes superior à do reservatório superficial, entretanto, a garantia associada da água superficial (90%) é bem superior à permanência da água disponível na BEA: apenas 28% nas áreas com solos profundos e 65% nas áreas com solos rasos.
Osorio, Barahona Rodomiro. "Conséquences biologiques des variations du climat, de l'intensité de la coupe mécanique et du pâturage sur deux espèces arbustives de la région aride du Chili." Montpellier 2, 1989. http://www.theses.fr/1989MON20089.
Full textFossati, Jacques. "Caractéristiques du système oued en milieu hyperaride, végétation des oueds du désert oriental septentrional (Egypte) et phytoécologique d'un secteur de l'oued Sannur." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10138.
Full textJuárez, Reyes Arturo Saul. "Étude de la digestibilité des pâturages naturels sahéliens sénégalais par la méthode de la pepsine-cellulase." Paris 6, 1986. http://www.theses.fr/1986PA066229.
Full textSaid, Ahmed Hami. "Etude de l’alimentation hydrique du palmier dattier (Phoenix dactylifera L.) dans le contexte pédoclimatique de la zone littorale de la République de Djibouti." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2034/document.
Full textDate palm is one of the few food crops adapted to the extreme weather conditions (drought, salinity), such as encountered in Djibouti. In the context of highly limited water resources, knowledge of the date palm water requirements is essential. The objective of this research was to determine the date palm water requirements, in the Djibouti pedoclimatic context, using in situ monitoring of water transport in the soil-plantatmosphere system, at the scale of a single date palm tree, and to quantify the date palm root water uptake. A fully developed date palm tree was instrumented at the irrigation basin scale, using several access tubes for neutron probe for monitoring the soil volumetric water content, and several tensiometers, installed from 10 to 160 cm depth. Three infiltration/redistribution experiments have been performed successively, the first without alteration of the soil-plant system, the second after cutting off a date palm tree while allowing the surface evaporation, the last with covering the soil surface to avoid evaporation. The results show large heterogeneity in soil hydraulic properties, with stratification linked to the coastline sedimentary context. The root water uptake is observed up to 80 cm depth. The date palm water requirements in the fresh period are estimated at 130 liters per day with a frequency of irrigation of one time every two weeks. For the first time, the date palm cultural coefficient has been established in the Djibouti climatic conditions (kc = 1.39). The obtained results will contribute to better management of irrigation and to improve the control of soil salinization in the pedoclimatic context of the Republic of Djibouti
Yavari, Ahmad. "Allocation des ressources naturelles renouvelables et le développement rural dans les milieux montagnards de l'Iran : exemple de modalités du développement rural et la dégradation des ressources naturelles végétales de l'Alborz central." Grenoble 1, 1996. http://www.theses.fr/1996GRE10277.
Full textFathi, Riyad Abdullah. "Étude et sélection de jeunes plants d'eucalyptus tolérants au sel, dans les populations de divers niveaux de variabilité." Nancy 1, 1987. http://www.theses.fr/1987NAN10292.
Full textGrouzis, Michel. "Structure, productivité et dynamique des systèmes écologiques sahéliens (Mare d'Oursi, Burkina Faso)." Paris 11, 1987. http://www.theses.fr/1987PA112339.
Full textThis work mainly deals with the spin crossover phenomenon in cobalt (II} molecular chemistry. The synthesis of a series of five and six coordinated complexes, with Schiff bases as equatorial ligands and various apical ones, are reported. The temperature dependances of magnetic susceptibilities and EPR spectra are used to study the influence of the environment on the metal ion spin state. The behaviours observed are interpreted on the basie of simple models. Evidence is provided for thermally induced s = 1/2 - s -= 3/2 spin crossavers. In other respects, a correlation can be established between the geometry and spin state of these complexes and their ability to activate molecular oxygen. In order to specify the spin-crossover mechanism, structural and thermodynamic techniques are used: the ingle-crystal X-ray structure of one of the compounds is reported; the mean variation of metal-ligand diatances upon transition is evaluated by X-ray absorption spectroscopy; enthalpy and heat capacity changes, measured by t ose, are compared with the values calculated on the basis of a phenomenological model. A new means of detecting the crossover, by using its effect r. N he EPR spectrum of a Cu (II)doping ion, is described in the case of an iron(II)complex
McGee, P. A. (Peter Allan). "Role of mycorrhizas in the regeneration of arid zone plants." 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phm1448.pdf.
Full textEaston, Lyndlee Carol. "Life history strategies of Australian species of the halophyte and arid zone genus Frankenia L. (Frankeniaceae)." 2008. http://catalogue.flinders.edu.au/local/adt/public/adt-SFU20081124.105244/index.html.
Full textDVORSKÝ, Miroslav. "Ecology of alpine plants in NW Himalaya." Doctoral thesis, 2014. http://www.nusl.cz/ntk/nusl-172974.
Full textAtkinson, Victoria. "Mine and industrial site revegetation in the semi-arid zone, North-Eastern Eyre Peninsula, South Australia." 2005. http://arrow.unisa.edu.au:8081/1959.8/46701.
Full textLangley, Gail. "Seed viability in topsoil stockpiles used for arid zone minesite rehabilitation in the Middleback Ranges of South Australia." 2002. http://arrow.unisa.edu.au:8081/1959.8/46671.
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