La gestion de l’irrigation et de la fertilisation dans les systèmes de production hors sol est particulièrement cruciale afin de limiter tous risques d’asphyxie racinaire, de lessivage d’éléments minéraux, voire de développement de pathogènes liés à une irrigation excédentaire, ou, à l’inverse, de réhumectation délicate et de stress hydrique de la plante dans des conditions limitantes en eau. Ayant pour finalité d’améliorer l’efficience de l’eau pour les plantes cultivées sur substrats, les travaux développés dans cette thèse ont visé à analyser l’évolution des propriétés hydrauliques de différents substrats au cours de laculture, en se focalisant tout particulièrement sur les effets combinés du développement racinaire et de la gestion de l’irrigation.Des essais culturaux ont été menés sur tourbe, fibres de coco, fibres de bois et écorce, prenant pour plante modèle utilisée le rosier Knock Out®. Des mesures de biomassesracinaires et aériennes, ainsi que celles des propriétés de rétention en eau et en air, de conductivité hydraulique, de diffusivité des gaz et de mouillabilité ont été effectuées surchaque substrat soumis à des régimes d’irrigation différents (variant d’un optimum hydrique à des conditions de stress hydrique). Les résultats montrent d'importantes modifications aufil du temps, principalement en raison de l'histoire hydrique. Cela conduit à des modifications(1) de la distribution et de la taille des pores, traduite par une réduction de leur tortuositéqui génère une augmentation de la diffusion gazeuse dans le milieu, ainsi que (2) unediminution de / Precise irrigation management of substrates is of vital importance in horticultural soilless systems to avoid root asphyxia, nutrient leaching, and plant disease in case of excessive watering; as well as, nutrient and water deficiency, and then plant physiological stress in the driest conditions. The study presented here aimed to improve water efficiency for plants grown in pots or containers, focusing on the evolution of hydraulic properties of substratesdue to root development and irrigation strategies during plant growth. Crop trials were performed on peat, coir, wood fiber and pine bark, using the rose Radrazz Rosa x hybrida as plant model.Shoot and roots biomasses, air and water retention properties, hydraulic conductivity, relative gas diffusivity and wettability were measured on each substrate, managed with different irrigation strategies (from an optimal water content to hydric stress conditions). Results showed significant changes over time, mainly due to the hydric history. This led to changes (1) in pore distribution and size, and then a decrease in pore tortuosity generating an increase in relative gas diffusivity in the substrates, and (2) a decrease in substrates’ wettability according to the intensity of drying. Although they were with weaker amplitude to those resulting of the hydric history, filling of macroporosity by the root system led to limit substrates’ consolidation due to drying/wetting cycles, and moreoverto amplify pore connectivity and then relative gas diffusivity and to limit degradation inwettability.

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-23Bitstream added on 2014-06-13T19:23:52Z : No. of bitstreams: 1 beckmanncavalcante_mz_dr_jabo.pdf: 1125665 bytes, checksum: 426ccb0fafd171f46150acdbb9eb8e03 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dentre as flores e plantas ornamentais, o crisântemo (Dendranthema grandiflora Tzevelev.) faz parte do elenco básico das floriculturas, porém, estudos referentes ao manejo da cultura ainda são necessários. Neste sentido, o presente trabalho teve por objetivo estudar no Brasil: i) o efeito de diferentes soluções nutritivas; e, ii) diferentes condutividades elétricas da solução nutritva e lixiviação de sais sobre o desenvolvimento e estado nutricional do crisântemo cv. Miramar cultivado em vaso; e na Alemanha: iii) caracterizar diferentes turfas e verificar a influência no crescimento e desenvolvimento do crisântemo cv. Sun City cultivado em vaso. No primeiro estudo, as diferentes soluções nutritivas não interferiram no diâmetro da haste, número e diâmetro de inflorescências e, massa seca de raízes, porém as soluções S3 e S4 promoveram a maior altura de plantas, área foliar, número de folhas, massa seca da parte aérea e total. No segundo estudo, o aumento da condutividade elétrica da solução nutritiva inibiu o desempenho vegetativo, o acúmulo de micronutrientes e de nitrogênio na massa seca foliar do crisântemo, porém estimulou o diâmetro da haste e os teores de P, K, Ca, Mg e S. A lixiviação dos sais promoveu maior crescimento das variáveis fitotécnicas e maior acúmulo foliar de micronutrientes nas plantas. No terceiro estudo, o conteúdo de sais solúveis (SS), N, P, K, densidade seca e capacidade de retenção de água incrementaram durante o cultivo, enquanto o espaço de aeração diminuiu em todas as turfas. O crescimento das plantas de crisântemo foi superior quando cultivadas na turfa SP-9 e com qualidade inferior em FBP-5. Os métodos VDLUFA e CEN apresentaram correlações significativas, embora os valores de pH, SS e concentrações de macro e micronutrientes das turfas não se encontraram dentro das faixas sugeridas como ideais. / Among the flowers and ornamental plants, chrysanthemum (Dendranthema grandiflora Tzevelev.) participate as basic flower in floricultures, but studies in relation to cultivation are necessary. In this way, the present work had as objective to study in Brazil: i) the effect of different nutritive solutions and, ii) electrical conductivity of nutritive solution and salt lixiviation on development and nutritional status of potted chrysanthemum “Miramar”; and in Germany: iii) to characterize peats and verify the influence of different peats on growth and development of potted chrysanthemum “Sun City”. In the first study, the different nutritive solutions did not interfere the stem diameter, number and diameter of inflorescence and root dry matter, although S3 and S4 solution promoted the highest plant high, leaf area, number of leaves, shoot and total dry matter. The second study show that an increase in electrical conductivity of nutritive solution inhibits de vegetative growth, micronutrient accumulation and nitrogen in leaf dry matter of chrysanthemum, but stimulate the stem diameter and P, K, Ca, Mg and S content. The lixiviation of salts stimulates plant growth and micronutrient accumulation in leaves. In the third study, the content of soluble salts, N, P, K, dry bulk density and water capacity increased during cultivation, but air capacity declined in all peats. Growth of chrysanthemum plants was higher in SP-9 whereas cultivation in FBP-5 led to the smallest plants. The CAT extracts in both VDLUFA and CEN methods presented significant correlations whereas values of pH, content of soluble salts, macronutrients and micronutrient of peats were not between the ideal limits suggested.

Resumo: Dentre as flores e plantas ornamentais, o crisântemo (Dendranthema grandiflora Tzevelev.) faz parte do elenco básico das floriculturas, porém, estudos referentes ao manejo da cultura ainda são necessários. Neste sentido, o presente trabalho teve por objetivo estudar no Brasil: i) o efeito de diferentes soluções nutritivas; e, ii) diferentes condutividades elétricas da solução nutritva e lixiviação de sais sobre o desenvolvimento e estado nutricional do crisântemo cv. Miramar cultivado em vaso; e na Alemanha: iii) caracterizar diferentes turfas e verificar a influência no crescimento e desenvolvimento do crisântemo cv. Sun City cultivado em vaso. No primeiro estudo, as diferentes soluções nutritivas não interferiram no diâmetro da haste, número e diâmetro de inflorescências e, massa seca de raízes, porém as soluções S3 e S4 promoveram a maior altura de plantas, área foliar, número de folhas, massa seca da parte aérea e total. No segundo estudo, o aumento da condutividade elétrica da solução nutritiva inibiu o desempenho vegetativo, o acúmulo de micronutrientes e de nitrogênio na massa seca foliar do crisântemo, porém estimulou o diâmetro da haste e os teores de P, K, Ca, Mg e S. A lixiviação dos sais promoveu maior crescimento das variáveis fitotécnicas e maior acúmulo foliar de micronutrientes nas plantas. No terceiro estudo, o conteúdo de sais solúveis (SS), N, P, K, densidade seca e capacidade de retenção de água incrementaram durante o cultivo, enquanto o espaço de aeração diminuiu em todas as turfas. O crescimento das plantas de crisântemo foi superior quando cultivadas na turfa SP-9 e com qualidade inferior em FBP-5. Os métodos VDLUFA e CEN apresentaram correlações significativas, embora os valores de pH, SS e concentrações de macro e micronutrientes das turfas não se encontraram dentro das faixas sugeridas como ideais. / Abstract: Among the flowers and ornamental plants, chrysanthemum (Dendranthema grandiflora Tzevelev.) participate as basic flower in floricultures, but studies in relation to cultivation are necessary. In this way, the present work had as objective to study in Brazil: i) the effect of different nutritive solutions and, ii) electrical conductivity of nutritive solution and salt lixiviation on development and nutritional status of potted chrysanthemum "Miramar"; and in Germany: iii) to characterize peats and verify the influence of different peats on growth and development of potted chrysanthemum "Sun City". In the first study, the different nutritive solutions did not interfere the stem diameter, number and diameter of inflorescence and root dry matter, although S3 and S4 solution promoted the highest plant high, leaf area, number of leaves, shoot and total dry matter. The second study show that an increase in electrical conductivity of nutritive solution inhibits de vegetative growth, micronutrient accumulation and nitrogen in leaf dry matter of chrysanthemum, but stimulate the stem diameter and P, K, Ca, Mg and S content. The lixiviation of salts stimulates plant growth and micronutrient accumulation in leaves. In the third study, the content of soluble salts, N, P, K, dry bulk density and water capacity increased during cultivation, but air capacity declined in all peats. Growth of chrysanthemum plants was higher in SP-9 whereas cultivation in FBP-5 led to the smallest plants. The CAT extracts in both VDLUFA and CEN methods presented significant correlations whereas values of pH, content of soluble salts, macronutrients and micronutrient of peats were not between the ideal limits suggested. / Orientador: Kathia Fernandes Lopes Pivetta / Coorientador: Paulo Affonso Bellingieri / Coorientador: Lourival Ferreira Cavalcante / Banca: José Geraldo Barbosa / Banca: Carolina Fernandes / Banca: Roberto Lyra Villas Boas / Banca: Jairo Augusto Campos de Araújo / Doutor