Made available in DSpace on 2014-08-20T14:36:56Z (GMT). No. of bitstreams: 1 Tese_ Carla_ Machado_ da_ Rosa.pdf: 1288182 bytes, checksum: 260f00e4ed48ff97092cf3316a59cb05 (MD5) Previous issue date: 2010-03-31 / In the south region from Rio Grande do Sul State, in,Brazil, 950 thousand hectares of soils are cultivated with rice, an important agricultural activity in that region, under an irrigation (flooded) system, using different soil management techniques. Studies regarding the organic matter (OM) dynamic in these soils are incipient, so this work aimed to evaluate the effect of irrigated rice management systems on the composition and quality of the OM from an Albaqualf, as well as, to investigate the OM stabilization mechanisms in this soil. Soil samples were collected in a long-term field experiment (21 years), from the 0-0,025, 0,025-0,05, 0,05-0,10 and 0,10-0,20 meters. The treatments evaluated are: ST traditional rice crop system: one year with rice crop under conventional tillage and two years of fallow; APC continuous rice crop system under conventional tillage and weeds control with herbicides; APD no-tillage system with rye-grass in the winter and rice in the summer; SN soil under natural conditions with native grassland. Soil samples were submitted to OM physical fractionation, and total organic carbon (TOC) and C contend in fractions were determinate by dry combustion analyzer, and carbon stocks adjusted according to the equivalent soil s mass. The chemical and molecular characteristics from this soil and OM fraction were determined by FTIR spectroscopy, RMN 13C (CP/MAS), and laser-induced fluorescence. No-tillage rice/rye-grass succession system was efficient in maintenance or increase SOM stocks until 0.05m deph. Particulate fraction increase demonstrates a higher maintenance level for carbon, showing the feasibility of this conservative system to contribute to the soil quality. Occluded light OM fraction was not susceptible to the effects of tillage systems used in irrigated rice crop, demonstrating a lower efficiency of the OM physical protection in soil aggregates. This situation may be related to the flooded condition affecting aggregates process. The OM spectroscopy characterization demonstrates for the flooded soil that functional groups are similar to the oxided soils. However, the portion of the CO-aquil structures from the free light and occluded light OM fraction were increased (from 39% to 52%), demonstrating a low level of OM decomposition in the deficient drainege environment. The OM from APC system were more humified than OM from APD and SN systems, mainly in the superficial levels, due to the loss of light OM fractions during the soil tillage. / A região sul do Estado do Rio Grande do Sul, Brasil, apresenta 950 mil hectares de solos de várzea, cultivados com arroz irrigado, em diferentes sistemas de manejo, constituindo uma das mais importantes atividades agrícolas para a região. O objetivo deste trabalho foi avaliar o efeito de sistemas de manejo de arroz irrigado sobre o conteúdo e qualidade da matéria orgânica do solo (MOS) de um solo representativo da região, bem como, buscar um maior entendimento dos mecanismos de estabilização da MOS neste solo. Amostras de um Planossolo Háplico foram coletadas em um experimento de campo de longa duração (21 anos), nas profundidades de 0-0,025, 0,025-0,05, 0,05-0,10 e 0,10-0,20 m, nos tratamentos: STSistema tradicional de cultivo: um ano arroz (preparo convencional) e dois anos com pousio; APC- Sistema de cultivo contínuo de arroz (preparo convencional) e controle de invasoras com herbicida; APD- Sucessão azevém/arroz em plantio direto e SN- Solo mantido com vegetação natural. As amostras foram submetidas aos fracionamentos granulométrico e densimétrico e o teor de carbono do solo e das frações da MOS quantificados em analisador de combustão seca, corrigindo-se os estoques de carbono pela massa equivalente de solo. As características químicas e moleculares do solo e das frações da MOS foram determinadas por espectroscopia de FTIR, RMN 13C (CP/MAS) e fluorescência induzida por lazer. O uso do solo sob o sistema sucessão arroz/azevém em plantio direto mostrou-se eficiente na manutenção ou incremento dos estoques de MOS do solo, até a profundidade de 0,05 m, e o incremento da fração grosseira conferiu um maior índice de manejo de carbono (IMC), mostrando a capacidade deste sistema conservacionista em promover a qualidade do solo. A fração leve oclusa da MOS não foi sensível aos efeitos dos diferentes sistemas de manejo utilizados no cultivo do arroz irrigado, evidenciando uma baixa eficiência da proteção física da MOS por oclusão em agregados, o que pode estar relacionada à condição de má drenagem no processo de agregação deste solo. A caracterização espectroscópica da MOS do solo de várzea mostrou que seus grupos funcionais são semelhantes aos de solos oxidados, no entanto, a proporção de estruturas CO-alquil das frações leve livre e leve oclusa foram elevados (39 a 52%), evidenciando um baixo grau de decomposição da MOS no ambiente mal drenado. A MO do sistema APC apresentou se mais humificada do que a MOS dos sistemas APD e SN, principalmente nas camadas superficiais, refletindo as perdas das frações mais lábeis da MOS, pelo preparo do solo.

More than 50% of the cultivated areas in the Southern Brazil and more than 60% of the cultivable area in Paraguay adopted the no-tillage system. This system went through several improvements, but there are still doubts about the fertilizing recommendation. Nitrogen (N) and potassium (P) are the nutrients absorbed in largest quantities and their deficiencies affect crop productivity. In this sense, the purpose of this study was to develop a nitrogen and potassium fertilizer recommendation system suitable for wheat, corn and soybean under no-tillage system in Paraguay. Seven field experiments were conducted in four Paraguayan Departments, which include the main grain production regions. Soils in these regions are mainly Oxisols , Inceptisols and Ultisols. Experimental design was random blocks with three replications. Treatments consisted of five rates of N for wheat (0, 30, 60, 90 e 120 kg ha-1 of N), five for corn (0, 60, 120, 180 e 240 kg ha-1 of N), and five rates of K (0, 25, 50, 75 e 100 kg ha-1 of K2O) for corn, wheat and soybean. Those nutrients there are not included in the study were properly supplied. For N, curves of these crops were made and maximum technical and economical efficiencies were calculated, as well as lavels of fertilizers recommended for corn and wheat under notillage system. For K, the soil critical level was determined, correlating level of K in the soil (determined by the method Mehlich 1) and the plant response (relative productivity). It was also determined lavels of K needed to attain the critical le vel in the soil and also to maintain it after it was reached. For wheat, it is necessary 35 kg ha-1 of N to reach 3100 kg ha-1 of wheat after soybean, and after corn it is necessary 30 kg ha-1 of N for a productivity of 2100 kg ha-1 of wheat. Wheat responds to residual N applied in corn. For a productivity of 6000 kg ha-1 of corn it is necessary 90 kg ha-1 after the wheat with little straw leftover. On the other hand, when there is a large quantity of straw and the no-tillage system is not stabilized, 130 kg ha-1 of N is needed. For a productivity of 8000 kg ha-1 of corn, 120 kg ha-1 of N is necessary in a consolidated no-tillage system. The critical level of K in the soil as determined by the Mehlich 1 method is 74 mg dm-3 for a relative productivity of 90%. To increase one mg dm-3 the level of K in the soil, 5 kg ha-1 of K2O is needed. At levels above 150 mg dm-3 plants do not respond to K application and only starting rates are recommended for wheat, corn and soybean crops. / O sistema plantio direto é adotado em mais de 50% das áreas do sul do Brasil e em mais de 60% de toda área cultivável do Paraguai. O sistema passou por várias adaptações, mas ainda permanecem dúvidas quanto à recomendação de adubação. O nitrogênio (N) e o potássio (K) são os nutrientes absorvidos em maior quantidade pelas plantas e suas deficiências afetam as produtividades. Neste sentido, o objetivo deste trabalho foi elaborar um sistema de recomendação de adubação nitrogenada e potássica adequado para trigo, milho e soja sob sistema plantio direto no Paraguai. Foram conduzidos sete experimentos em rede, em quatro departamentos do Paraguai, englobando as principais regiões produtoras de grãos. Os solos dessas regiões são principalmente Oxisols, Inceptisols e Ultisols. O esquema experimental foi de blocos ao acaso com três repetições. Os tratamentos constaram de cinco doses de N para trigo (0, 30, 60, 90 e 120 kg ha-1 de N), cinco para milho (0, 60, 120, 180 e 240 kg ha-1 de N) e cinco doses de K (0, 25, 50, 75 e 100 kg ha-1 de K2O) para trigo, milho e soja. Os elementos que não estavam em estudo foram supridos adequadamente. Para N foram determinadas as produtividades das culturas, elaboradas as curvas de resposta e calculadas máxima eficiência técnica e econômica, assim como as doses recomendadas para o milho e o trigo sob sistema plantio direto. Para o K, foi determinado o teor crítico no solo, correlacionando o teor de K no solo (determinado pelo método de análise Mehlich 1) e a resposta das plantas (rendimento relativo). Foram determinadas as doses de K necessárias para alcançar o teor crítico no solo e para mantê -lo depois de atingido. Para o trigo são necessários 35 kg ha-1 de N para atingir 3100 kg ha-1 de trigo após a soja, e após o milho são necessários 30 kg ha-1 de N para produtividade de 2100 kg ha-1 de trigo. O trigo responde ao residual de N aplicado no milho. Para produtividade de 6000 kg ha-1 de milho são necessários 90 kg ha-1 de N após o trigo com pouca palha. Já quando há grande quantidade de palha e o sistema plantio direto não está estabilizado, são necessários 130 kg ha-1 de N. Para produtividades de 8000 kg ha-1 de milho são necessários 120 kg ha-1 de N num sistema plantio direto consolidado. O teor crítico de K no solo determinado pelo método Mehlich 1 é de 74 mg dm-3 para rendimento relativo de 90%. São necessários 5 kg ha-1 de K2O para elevar em um mg dm-3 o teor de K no solo. Com teores acima de 150 mg dm-3 no solo, as plantas geralmente não apresentam resposta à aplicação de K, recomendando-se somente dose de arranque para as culturas de trigo, milho e soja.

In the cassava production the conventional tillage, characterized by soil preparation with intensive mobilization, is commonly used. However, when this practice results in the maintenance of small quantities of straw on the soil surface, the erosion becomes imminent, and it is exacerbated by the spacing and slow initial development of this culture, especially until four months after planting. An alternative is the no-tillage system, a type of conservation tillage, in which only the owing/planting furrow is prepared for the deployment of culture, and is widely used in soybean, corn, wheat, beans, and others crops. For cassava, the adoption of this system has raised many questions on the basis of the soil physical properties recommended, according to which the crop requires well-drained and loose soils to allow the proper root development, where the carbohydrates produced by the plant are stored. It is believed that the deployment of a larger soil area in furrow may facilitate the proper development of cassava in no-tillage system and promote the soil protection due the maintenance of straw on the surface. In this context, the objective is improve the furrow opener device of cassava planters using the precepts of the agricultural machinery development process, with the intent of provide the cultivation of cassava in no-tillage system. For the furrow opener development it were implemented the informational, preliminary and detailed design phases of the product development process. It where formulated for the task of preparing the planting furrow, 31 needs of customers who were deployed in 30 customer requirements and then in 27 design requirements. From these requirements and the solutions available on other agricultural machines and implements, the winged tines where selected as a potential solution. So, a layout study where conducted and resulted in the construction of prototypes with different geometries to experimentation with cassava crop and tests of forces. The use of the reference model for the development process of agricultural machinery allowed the development of furrow opener device for the cultivation of cassava in no-tillage system, that have low cost, small number of components, simple manufacturing process and smooth operation. The yield obtained with the cassava crop in conventional tillage and no-tillage was similar, showing that this technique can be used to grow without com / No sistema de produção da mandioca o preparo convencional do solo (intenso revolvimento) é comumente utilizado. Quando esta prática resulta na manutenção de pequenas quantidades de palha sobre o solo, o problema da erosão se torna eminente e é agravado pelo espaçamento entre linhas e o lento desenvolvimento inicial desta cultura, principalmente até os quatro meses após o plantio. Uma alternativa é o sistema plantio direto, em que apenas o sulco de semeadura/plantio é preparado durante a implantação da cultura, e é largamente utilizado nas culturas de soja, milho, trigo, feijão, entre outras. Para a mandioca, a adoção deste sistema tem gerado muitas dúvidas em função das condições físicas do solo recomendadas, segundo as quais a cultura requer solos bem drenados e soltos para possibilitar o adequado desenvolvimento das raízes. Acredita-se que a mobilização de uma maior área de solo no sulco de plantio possa viabilizar o adequado desenvolvimento da mandioca em sistema plantio direto e favorecer a proteção do solo pela manutenção da palha sobre superfície. Nesse contexto, objetivou-se aperfeiçoar o mecanismo sulcador de plantadoras de mandioca utilizando os preceitos do processo de desenvolvimento de máquinas agrícolas, com o intento de viabilizar o cultivo de mandioca em sistema plantio direto. Para o desenvolvimento do mecanismo foram executadas as fases de projeto informacional, preliminar e detalhado. Formularam-se, para a função de preparar o sulco de plantio, 31 necessidades de clientes que foram desdobradas em 30 requisitos de clientes e posteriormente em 27 requisitos de projeto. A partir destes requisitos e das soluções disponíveis em outras máquinas e implementos, selecionou-se a haste sulcadora alada como potencial solução. Desta forma, realizou-se um estudo de leiautes que culminou na construção de protótipos com diferentes geometrias para testes, experimentação com a cultura da mandioca e ensaio de esforços. A utilização do modelo de referência para o processo de desenvolvimento de máquinas agrícolas permitiu o desenvolvimento de uma haste sulcadora alada de baixo custo, pequeno número de componentes, processo de fabricação simples e bom funcionamento. A produtividade obtida com a cultura da mandioca em preparo convencional e sistema plantio direto foi semelhante, evidenciando que esta técnica pode ser utilizada para o cultivo sem comprometer a produtividade e ainda melhorar a sustentabilidade do sistema.

Liming is used to decrease soil acidity and increase exchangeable calcium and magnesium levels, but it may impaired calcium and magnesium ratios with continuous use of dolomitic or calcitic lime. The aim of this work is to evaluate the efficiency of different proportions of calcitic and dolomitic lime on soil acidity neutralization, evaluated by crop yields and in the Ca and Mg levels in plant. Four experiments were carried out in different physiographic regions of Rio Grande do Sul in October 2004 and carried on until March 2006, with two soybean (Glycine max L. Merril) and black oat (Avena strigosa Schieb)crops. The treatments were constituted by the following calcitic and dolomitic lime proportions: control without lime; 100% calcitic; 75% calcitic and 25% dolomitic; 50% calcitic and 50% dolomitic; 25% calcitic and 75% dolomitic and 100% dolomitic, arranged in randomized block design with subplot with four replications, being the main plots constituted by surface and incorporated methods and the secondary plots were submitted to the lime proportions. The black oat dry matter yield, the soybean grains yield and the levels of Ca and Mg in the soybean and black oat tissue were evaluated. In soil samples collected in layers from 0 5; 5 10; 10 -15; 15 20; 0 10 e 0 - 20 cm, the Ca, Mg e Al, exchangeable levels, pH H2O, SMP index, bases saturation and the Ca/Mg ratios were determined. All the variants were submitted to the variance analysis at 5% and when significant, the means were compared by the Tukey test at 5%. The results show that the Ca/Mg ratio and the lime application methods did not have influenced in the soybean and black oat yield. The Ca and Mg levels in the tissue were not influenced by the Ca/Mg ratios. The acidity neutralization, the exchangeable Al neutralization, the increasing of the Ca and Mg levels and the base saturation only occurred in the layer of 0-5 cm on the surface application and until the layer of 10-15 cm in the incorporated application. / A aplicação de calcário, além de corrigir a acidez do solo, eleva os teores de cálcio e de magnésio, alterando a relação Ca/Mg no solo, levando técnicos e produtores a levantar a hipótese de que o uso continuado de calcários que fornecem relações Ca/Mg inadequadas poderia promover um desequilíbrio iônico entre o Ca e o Mg no solo e afetar o desenvolvimento das culturas. O objetivo deste trabalho foi avaliar a eficiência de diferentes proporções de calcário calcítico e dolomítico na correção da acidez do solo, na produtividade de diferentes culturas e nos teores de Ca e Mg no tecido vegetal em sistema de plantio direto. Foram instalados quatro experimentos em diferentes regiões fisiográficas do Estado do Rio Grande do Sul em outubro do ano de 2004 e conduzidos até março de 2006, totalizando dois cultivos de soja e um cultivo de aveia preta. Os tratamentos foram constituídos pelas seguintes proporções de calcário calcítico e dolomítico: Testemunha; 100 % calcítico; 75 % calcítico e 25 % dolomítico; 50 % calcítico e 50 % dolomítico; 25 % calcítico e 75 % dolomítico e 100% dolomítico, arranjados em delineamento de blocos ao acaso com parcelas subdivididas com quatro repetições, sendo as parcelas principais constituídas pelos modos de aplicação superficial e incorporada e as subparcelas submetidas as proporções de calcário. Foram avaliadas a produção de matéria seca de aveia preta, rendimento de grãos de soja e teores de Ca e Mg no tecido vegetal da soja e da aveia preta. Em amostras de solo coletadas nas camadas de 0 5; 5 10; 10 -15; 15 20; 0 10 e 0 - 20 cm, foram determinados os teores trocáveis de Ca, Mg e Al, pH H2O, índice SMP, saturação por bases e relações Ca/Mg. Todas as variáveis foram submetidas à análise da variância a 5% e quando significativas, as médias foram comparadas pelo teste de Tukey a 5 %. A relação Ca/Mg e os modos de aplicação de calcário não tiveram influência na produtividade de aveia e soja. Os teores de Ca e de Mg no tecido não foram influenciados pelas teores relações Ca/Mg do solo. A correção da acidez, neutralização do Al trocável, elevação dos teores de Ca e Mg e saturação por bases somente ocorreu na camada de 0-5 cm na aplicação superficial e até a camada de 10-15 cm na aplicação incorporada.

Le travail de recherche mené au cours de cette thèse a permis de mettre en place le modèle MOSST, un modèle de structure du sol basé sur des voxels et en 3D. Le sol simulé est séparé en trois niveaux : (i) celui des voxels qui sont la plus petite échelle prise en compte dans le modèle ; c'est aussi au niveau des voxels qu'est stockée l'information relative à la structure du sol, chaque voxel possède un état qui correspond à un composant du sol : ex. vides, solides, matières organiques; (ii) celui des pièces qui sont des cubes de 40 voxels de coté et (iii) celui du bloc de sol qui représente (taille et forme) l'ensemble de l'environnement simulé. Pour pallier aux contraintes du stockage informatique de la structure du sol, un système d'encodage a été mis en place ainsi qu'un système de chargement dynamique de la structure qui permet de charger et décharger une partie de la structure virtuelle. Ce modèle à la particularité de pouvoir être initialisé à partir d'images 3D, issues de la tomographie aux rayons X, ce qui permet d'initialiser un sol virtuel avec une structuration réelle. Le modèle MOSST a été conçu pour être le plus générique possible permettant ainsi son adaptation et son évolution en fonction des agents structurants associés. Un premier couplage a été réalisé avec un modèle d'agent ver de terre qui permet de simuler la production de déjections et le creusement de galeries par les vers de terre anéciques et endogés. Ce modèle d'agent ver de terre apporte une innovation importante : un système de gestion des galeries qui guide les vers lorsqu’ils creusent. Il simplifie aussi l’implémentation des anéciques et empêche les agents vers de terre d'avoir des comportements non réalistes tels que recreuser dans leurs propres galeries. Une analyse de sensibilité de ce modèle, a démontré l'importance de la vitesse de creusement dans la simulation de l'activité de bioturbation des vers. Une première calibration a été réalisée à l'aide des données issues de la littérature complétées par des données issues d’une étude en microcosmes sur l'activité de bioturbation de trois vers de terre endogés (A. caliginosa, A. chlorotica, A. icterica). Nous avons montré que A. chlorotica peut être assimilée à une espèce épi-endogée en lien avec son activité principalement localisée sur les premiers centimètres de sol tandis que la bioturbation de A. icterica correspond à celle d’un endogé strict. Afin de rendre compte de l'impact d'outils de travail du sol sur la structure, une expérience en plein champ nous a permis de préciser l’évolution de la structure du sol, au cours des étapes de semis dans un système en labour. Le labour entraîne une augmentation de la porosité, la reprise de labour une décroissance rapide de la porosité jusqu’à environ 5-7 cm et un tassement des couches plus profondes par rapport à la situation post-labour. / We built up the model MOSST, a MOdel of Soil STructure in 3-dimensional and based on voxels. In this model, soil is split in three levels : (i) the voxel one, voxel is a cube that represents the smallest simulated feature. Every voxel holds a state that corresponds to a soil element, e.g. organic matter, void, solid, etc; (ii) the piece level, pieces are cubes of 40 voxels side; (iii) soil block one which gives the shape and size of the simulated environment. To overcome memory constraints while large soil structures are simulated, an encoding of the pieces and a system to dynamically load and unload parts of the environment were implemented. One of the interesting features of MOSST is that it can be initialized using 3D images, e.g. from X-ray tomography, and thus be initialized with a real structuring. MOSST was built in order to be as generic as possible and therefore it may be coupled and adapted to numerous structuring processes. A first coupling was done with a model of earthworm agents which simulates the burrowing and cast production of anecic and endogeic earthworms. This model introduces an innovating system to manage burrow paths which simplifies anecic earthworm implementation and forbids some impossible behaviours such as to burrow inside an existing burrow. A sensitivity analysis of this model showed that earthworm's burrowing speed is a main factor affecting their bioturbation. A first calibration was performed using data available in the literature and data from a study in microcosms on three endogeic earthworms bioturbation (A. caliginosa, A. chlorotica, A. icterica). It was shown that A. chlorotica holds an epi-endogeic behaviour because it bioturbates the soil mostly in the top few centimetres whereas A. icterica has a true endogeic behaviour. To account for tillage impact on soil structure, a field experiment was performed in order to compare soil structure development during tillage steps in a ploughed system. Ploughing led to an increase in soil macroporosity, sowing combined with a rotary harrowing led to a sharp decline in soil macroporosity to a depth of 5-7 cm with a macroporosity deeper in the soil which is smaller than after ploughing. A comparison of soil structure was performed after sowing in three tillage systems : ploughing (P), superficial tillage (ST) and direct seedling (DS). Soil macroporosity was the lowest in DS and was the same within the first 7 cm in P and ST. Deeper in the soil ST is less porous than P. The work carried out is the foundation of a model that aims at simulating soil structure dynamics in various farming practices. The coupling of MOSST with new structuring agents such as compaction due to tillage or root growth is now needed to improve the model. The acquisition of new data is also needed to improve the model of earthworm bioturbation.

Fusarium graminearum est un champignon pathogène des plantes, responsable de la fusariose de l'épi (plus connue sous le nom de Fusarium Head Blight : FHB) sur céréales, notamment sur le blé et le maïs. En interaction avec la plante, le champignon produit des mycotoxines, parmi lesquellse le déoxynivalénol (DON), dont la finalité pour le champignon producteur est méconnue mais qui sont toxiques pour les humains et les animaux. Ainsi la qualité des grains contribue fortement aux pertes de rendement observées et les résidus contaminés restent au champ. Une première revue bibliographique (Leplat et al 2012) a mis en évidence l'importance des résidus de culture (habitat écologique) pour la survie saprophyte du champignon, pour sa reproduction sexuée et pour l'établissement de l'inoculum primaire susceptible d'infecter la prochaine culture. Une seconde revue bibliographique a souligné les lacunes en ce qui concerne le rôle que les mycotoxines pourraient jouer dans la survie de F. graminearum dans un cet habitat. L'objectif principal de cette thèse était donc de vérifier si la présence de mycotoxines dans les résidus de récolte donne un avantage compétitif à F. graminearum vis-à-vis des composantes biotiques du sol et des résidus et notamment les champignons, les bactéries, les protozoaires, les nématodes et les vers de terre. L'impact du DON sur ces différentes communautés a été évalué dans des résidus de maïs et de blé, au champ et en microcosmes, en condition de labour et de travail superficiel du sol. Le développement de la maladie et ses conséquences sur le rendement ont été observés dans l'expérience de terrain à l'Unité Expérimentale de l'INRA de Dijon.Au cours de cette étude, la survie et les dynamiques de développement de la souche modèle d'étude F. graminearum MIAE00376 et des communautés fongiques et bactériennes ont été mesurées en utilisant la réaction de polymérisation en chaîne en temps réel (Q-PCR) ainsi que par comptage sur boîtes. Dans le même temps, l'évolution des structures des communautés microbiennes a été déterminée par analyse du polymorphisme de longueur des fragments de restriction terminaux (T-RFLP). Les nématodes et les vers de terre ont été quantifiés par extraction et observations à l'œil ou a la loupe binoculaire. Le DON introduit dans le sol et les résidus a été extrait et quantifié au cours du temps par chromatographie liquide haute performance (CLHP). Des dynamiques de population de la souche MIAE00376 associée à différents microorganismes isolés de paille en décomposition et sélectionnés pour leur résistance au DON, à des bactéries fixatrice d'azote et à des Fusarium sp. appartenant au complexe fongique du FHB ont été mesurées en microcosmes de paille en présence ou non de DONLes résultats suggèrent que le DON dans les résidus de culture a une incidence sur les composantes biotiques du sol, mais l'impact dépend des communautés et de la localisation des résidus (en surface ou incorporés dans le sol). La biomasse moléculaire montre que les densités bactériennes et fongiques ont été significativement affectées par la présence de DON. La présence de DON a joué un rôle significatif sur la structure des communautés bactériennes et protozoaires, plus faible sur les communautés fongiques et nul sur les nématodes voire positif sur les vers de terre.Il est conclu que le DON est rapidement inaccessible en profondeur et un peu moins rapidement en surface (immobilisation ou dégradation), qu'il ne confère pas d'avantage compétitif au champignon producteur et que la gestion de l'habitat privilégié que constituent les résidus de culture pour F. graminearum peut être envisagée par le travail du sol en favorisant la décomposition rapide des résidus, par le labour ou l'utilisation d'organismes décomposeurs indigènes ou introduits. / Fusarium graminearum is a plant pathogenic fungus, causing devastating disease “Fusarium head blight” (FHB) in cereals including wheat and maize. It also contaminates the grains with mycotoxins including deoxynivalenol (DON) which are toxic to human and animals. This disease has resulted in the serious losses in grain yield and quality. We established through a first bibliographic review that during off season fungus survives saprophytically on the crop residues (ecological habitat) and serves as primary inoculum for the next season crop. However, we noticed also that the literature was poor about the role mycotoxins could play in the establishment of F. graminearum in such a habitat. The main aim of this thesis was therefore to test whether the presence of mycotoxins in the crop residues gives an advantage to F. graminearum to survive and develop a primary inoculum in the presence of the whole soil biota including fungi, bacteria, protozoa, nematodes and earthworms. We studied the impact of DON on the soil communities in the field as well as in microcosms, in wheat as well as in maize residues under tillage and no-tillage conditions. The disease development and the yield were noted in the field experiment. Some DON resistant active fungal decomposers and nitrogen fixing bacteria were picked and the dynamics of F. graminearum was observed by accelerating decomposition of crop residue in their presence, in the presence or absence of DON.During this study, the dynamic and survival of F. graminearum and total fungal and bacterial communities were examined by using quantitative real time polymerase chain reaction (qPCR) as well as by plate counting. At the same time, the structures of microbial communities were determined by using terminal restriction fragment length polymorphism analysis (T-RFLP). The DON resistance of isolated fungal decomposers and nitrogen fixers was tested by using minimal inhibitory concentration test (MIC). Nematodes and earthworms were quantified through binocular observations. The fate of DON was determined by quantifying the mycotoxin by high performance liquid chromatography (HPLC).The results suggested that DON in crop residues showed an impact on the biotic components of the soil but the impact depended on the communities and on the location of the residues (on surface or incorporated in the soil). The molecular biomass shows that the fungal and bacterial densities were significantly affected by the presence of DON. The presence of DON played significant role on the structure of bacterial and protozoan community while the nematodes and fungal communities remained unaffected. MIC results showed that the susceptibility of some competitive fungal strains towards DON was dependent on the dose of mycotoxin. The earthworms (Lumbricus terrestris) were not affected by the presence of mycotoxin. The degradation of DON in the residues was dependent on the time, the location of residues and the soil biota. The quantification of F. graminearum suggested that the presence of DON gave no advantage in the survival and development of primary inoculum during the decomposition of crop residues in the soil. We conclude that fungal decomposers can be selected on their enzymatic potential towards organic matter more than on the DON resistance to increase the degradation of the straw left at the surface and limit the subsequent development of F. graminearum.

Submitted by Michele Mologni (mologni@unoeste.br) on 2017-08-30T14:33:02Z No. of bitstreams: 1 Luanda Torquato Feba.pdf: 340214 bytes, checksum: dc9c820ea8f82e5c02bacb4259c0c1a5 (MD5) / Made available in DSpace on 2017-08-30T14:33:02Z (GMT). No. of bitstreams: 1 Luanda Torquato Feba.pdf: 340214 bytes, checksum: dc9c820ea8f82e5c02bacb4259c0c1a5 (MD5) Previous issue date: 2016-08-04 / The objective of this research was to evaluate the effect of different forms of grazing reimplantation with and without phosphating in soybean productivity. The experiment was conducted at the Experimental Farm of the University of West Paulista (UNOESTE), located in the municipality of Presidente Bernardes - SP, January 2014 to February 2015. It was conducted in a split plot design in tracks, with four replications. The plots consisted of four grazing reimplantation systems with 4 kg ha-1 Urochloa brizantha (grass - Marandu) (Natural Bank Seed (BNS); BNS + Sowing the haul; BNS + Seeding online; BNS + Seeding in line intercropped with soybeans) and subplots (with and without phosphorus fertilization). The variables analyzed were: number of tillers and dry matter yield (PMS); analysis of plant tissue pasture; chemical analysis of the pasture; Leaf analysis analysis in soybean; production of components and soybean productivity. The variables analyzed in each treatment were submitted to analysis of variance (p <0.05) and the means were compared by Tukey test (p <0.05) through Sisvar software. In this context, it can be concluded that the soybean yield was higher with the reintroduction of grazing intercropped with soybean. This treatment led to an increase of 276 kg ha-1 in relation to the treatment that there was no grazing reimplantation (BNS). Phosphate Fertilization increased the phosphorus content in the soil; in the dry matter production of soybean; the leaf phosphorus content and productivity of soybean. / O objetivo dessa pesquisa foi avaliar o efeito de diferentes formas de reimplantação de pastagem com e sem fosfatagem na produtividade da soja. O experimento foi conduzido na Fazenda Experimental da Universidade do Oeste Paulista (UNOESTE), localizada no município de Presidente Bernardes – SP, em Janeiro de 2014 a Fevereiro de 2015. Foi realizado em faixas em esquema de parcela subdividida, com quatro repetições. As parcelas foram constituídas por quatro sistemas de reimplantação de pastagem com 4 kg ha-1 de Urochloa brizantha (capim - Marandu) (Banco Natural de Semente (BNS); BNS + Semeadura à lanço; BNS + Semeadura em linha; BNS + Semeadura em linha consorciada com soja) e as subparcelas, (com e sem adubação fosfatada). As variáveis analisadas foram: número de perfilhos e produtividade de massa seca (PMS); análise do tecido vegetal da pastagem; análise bromatológica da pastagem; análise de diagnose foliar na soja; componentes de produção e produtividade da soja. As variáveis analisadas em cada tratamento foram submetidas à análise de variância (p<0.05) e as médias foram comparadas pelo teste Tukey (p<0.05) por meio do software Sisvar. Neste contexto, pode se concluir que a produtividade da soja foi maior com a reimplantação da pastagem consorciada com a cultura da soja. Esse tratamento proporcionou um acréscimo de 276 kg ha-1 em relação ao tratamento que não houve reimplantação de pastagem (BNS). A adubação fosfatada proporcionou aumento do teor de fósforo no solo; na produção de massa seca da soja; no teor de fósforo foliar e maior produtividade da soja.

Agronomic outcomes are the product of a plant's genotype and its environment. Genomic technologies allow farmers and researchers new avenues to explore the genetic component of agriculture. These technologies can also enhance understanding of environmental effects. With a growing world population, a wide variety of tools will be necessary to increase the agronomic productivity. Here I use massively parallel, deep sequencing of RNA (RNA-Seq) to measure changes in cotton gene expression levels in response to a change in the plant's surroundings caused by conservation tillage. Conservation tillage is an environmentally friendly, agricultural practice characterized by little or no inversion of the soil prior to planting. In addition to changes in cotton gene expression and biological pathway activity, I assay the transcriptional activity of microbial symbiotes living in and around the cotton roots. I found a large degree of similarity between cotton individuals in different treatments. However, under conventional disk tillage I did find significantly greater activity of cotton phosphatase and sulfate transport genes, as well as greater abundance of the microbes Candidatus Burkholderia brachynathoides and Arthrobacter species L77. This study also includes the use of high-throughput physical mapping of DNA to examine the genomic structure of a wild cotton species, Gossypium raimondii, which is closely related to the economically significant crop species Gossypium hirsutum. This technology characterizes genomic regions by assembling large input DNA molecules labeled at restriction enzyme recognition sites. I created an efficient algorithm and generated 812 whole genome assemblies from two datasets. The best of these assemblies allowed us to detect 3,806 potential misassemblies in the current release of the G. raimondii genome sequence assembly.

Orientador: Ciro Antonio Rosolem / Banca: Leonardo Theodoro Büll / Banca: Carlos Alexandre Crusciol / Banca: Luís Ignácio Prochnow / Banca: Eduardo Fávero Caires / Resumo: Estudou-se a substituição de fosfato solúvel por reativo em soja cultivada em semeadura direta. O experimento foi conduzido nos anos agrícolas de 2001/2002 e 2002/2003 em Latossolo Vermelho distroférrico, textura média, em um delineamento experimental em blocos casualizados com parcelas subdivididas, com quatro repetições. No mês de abril de 2001, foram aplicados nas parcelas, a lanço, em superfície, três tratamentos: 1) sem aplicação de P2O5; 2) aplicação de 80 kg ha-1 de P2O5 de superfosfato triplo e 3) aplicação de 80 kg ha-1 de P2O5 de fosfato natural Arad. Em seguida, semeou-se o triticale (X Triticosecale Wittmack) que foi conduzido até a colheita. Em setembro de 2001, após a colheita do triticale, semeou-se o milheto (Pennisetum glaucum (L.) R. Brown) com o objetivo de elevar a cobertura de palha do solo, sendo dessecado com herbicida no florescimento. No início de dezembro de 2001, após o dessecamento do milheto, foi instalada a cultura da soja (Glycine Max (L.) Merrill) aplicando-se combinações de fontes de fosfato solúvel e natural no sulco de semeadura. Em maio de 2002, após a colheita da soja, foi semeada a aveia preta (Avena strigosa Schreb), dessecada com herbicida no florescimento. No mês de agosto de 2002, foi semeado o milheto (Pennisetum glaucum (L.) R. Brown) sendo dessecado em dezembro de 2002, quando a soja foi novamente semeada. No primeiro ano, foram avaliadas as culturas do triticale, milheto e soja, enquanto que, no segundo, apenas a cultura da soja. As avaliações no primeiro ano constaram de: analise química de solo; produção de matéria seca de plantas e palha de cobertura; teor e quantidade de fósforo nas plantas de triticale e palha de cobertura de triticale, milheto e soja; teor e quantidade de fósforo nos grãos, densidade de plantas e produção de triticale e, teor e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The substitution of soluble by natural phosphate in soybean cropped under no tillage was studied. The experiment was carried out in no tillage system for two seasons (2001/2002 and 2002/2003) in a Red Latosol dystropherric, medium texture, in a split-plot design in complete randomized blocks, with four replications. On April, 2001, phosphates were applied on the plots, broadcast on the soil surface, as follows: 1) without P2O5; 2) application of 80 kg ha-1 of P2O5 as triple superphosphate and 3) application of 80 kg ha-1 of P2O5 as Natural Phosphate Arad. Following it, triticale (X Triticosecale Wittmack) was planted and grown up to grain harvest. On September, 2001, after triticale harvest, pearl millet (Pennisetum glaucum (L.) R. Brown) was grown to raise the amount of straw on soil surface. It was chemically desiccated at flowering. At the beginning of December, 2001, after millet desiccation, soybean (Glycine max (L.) Merrill) was planted in the sub plots, using combinations of soluble and natural P sources, applied in the seed furrow. On May, 2002, after soybean harvest, black oat (Avena strigosa Schreb) was planted, grown up to flowering and chemically desiccated. On August, 2002, pearl millet was planted again and desiccated on December, 2002, when soybean was planted again. In the first year, triticale, millet and soybean were evaluated and in the second year, only soybean was evaluated. The evaluations in the first year consisted of: soil fertility, dry matter and straw production, phosphorus contents in the plants and straw in triticale, pearl millet and soybean; phosphorus contents in the grains, plant density, yield in triticale; and phosphorus contents in the grains, leaf diagnosis, yield components, plant population, and yield in soybean. In the second year, evaluations were, in soybeans: soil fertility, dry matter production and straw... (Complete abstract, click eletronic address below) / Doutor

Orientador: Carlos Alexandre Costa Crusciol / Banca: Dirceu Maximino Fernandes / Banca: Edson Lazarini / Banca: José Salvador Simoneti Foloni / Banca: Denizart Bolonhezi / Resumo: Estudos relacionados ao cultivo de amendoim no sistema de semeadura direta são escassos, principalmente relacionados com aplicação superficial de calcário e gesso. A aveia branca é uma das alternativas para o cultivo de inverno no Brasil, por produzir grãos para alimentação humana, forragem e adubo verde, diversificando a atividade agrícola, no entanto são inexistentes na literatura informações a respeito da calagem e gessagem superficiais nesta cultura. Em função do exposto, o presente trabalho teve por objetivo avaliar o comportamento das culturas de amendoim e aveia branca cultivadas no sistema semeadura direta, em área com aplicação superficial de calcário e gesso, bem como as conseqüências no movimento de bases no perfil do solo, na concentração de cátions solúveis na parte aérea, na nutrição e produtividade das culturas. O experimento foi conduzido nos anos agrícolas de 2004/2005 e 2005/2006 na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas - Campus de Botucatu, num Latossolo Vermelho distrófico. Foi utilizado o delineamento experimental em blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas foram constituídas pela aplicação de quatro níveis de calcário dolomítico com PRNT = 71,2. As doses de calcário foram definidas de acordo com a análise química do solo na profundidade 0-0,2m para elevar a saturação por bases a 70% (2.000 kg ha- 1), metade da dose recomendada (1.000 kg ha-1), o dobro da dose recomendada (4.000 kg ha-1) e uma testemunha (sem aplicação). As subparcelas foram constituídas pela ausência e presença da aplicação de 2.100 kg ha-1 de gesso agrícola. Como cultura de verão foi utilizado o cultivar de amendoim (IAC 886) nos dois anos de condução do experimento em toda a área experimental e como cultura de inverno foi utilizado o cultivar de aveia branca (IAC 7) nos dois anos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: There have been few studies about peanut crop in no-tillage system mainly about superficial liming and gypsum application. White oat is an alternative for winter cropping in Brazil to be used as human food, forage and green manure; nevertheless, there is no information about superficial liming and gypsum application for this crop. Therefore, the objective of this work was to evaluate peanut and white oat yield as affected by superficial liming and gypsum application in no-tillage system as well as base movement in soil profile, concentration of water-soluble cations in the shoot of plants and plant nutrition. The experiment was carried out in the growing seasons of 2004/2005 and 2005/2006 in Botucatu, São Paulo State, Brazil, on a dystrophic Red Latosol. The experimental design was the completely randomized block with subdivided plots and four replications. The main plots consisted of four dolomite limestone levels with neutralization power of 71.2. Limestone levels were determined by soil chemical analysis in the 0-0.20m depth; the aim was to apply the recommended dose to raise base saturation up to 70% (2000 kg ha-1), half of the recommended dose (1.000 kg ha-1) and twice the recommended dose (4000 kg ha-1) besides the control, with no application. Subplots consisted of areas with and without gypsum application (2000 kg ha-1). Peanut (cultivar IAC 886) and white oat (IAC 7) consisted of the summer and winter crops cultivated in two growing seasons, respectively. The results of the present research showed that superficial liming affected soil acidity and increased Ca and Mg levels in the soil profile along with gypsum application, which contributed for the effects to be observed in deeper layers. Then, it was found that superficial liming showed residual effects and allowed fine lime particles to move down in the soil profile... (Complete abstract click electronic access below) / Doutor