Made available in DSpace on 2014-07-29T15:16:33Z (GMT). No. of bitstreams: 1 Dissertacao_Daiana_Fernandes.pdf: 425302 bytes, checksum: 7de511c42aac920ca200b0a0f5e3892e (MD5) Previous issue date: 2009-04-30 / The soybeans and beans are of great economic and social importance to Brazil. From the nutritional point of view, they are very demanding in nitrogen and to supply its demand both species are able Biological Nitrogen Fixation (BNF). However, for the BNF, rhizobia require energy supply by the carbohydrates from photosynthesis. For this reason the availability of fotossintato is the biggest limiting factor in BNF. This work had as propose to evaluate the influence of inoculation with rhizobia in two phenological stages of plants under different levels of shading. In this context the inoculation was assessed by the following treatments: two species of legume (Phaseolus vulgaris, L. and Glycine max, L.) inoculated and not inoculated (Fi, Fni, Si and Sni) with specific strains (Rhizobium tropici and Bradyrhizobium japonicum and B. elkanii) in two phenological stages (before, Ep1, and after flowering, Ep2) and subjected to three shadow levels (no shade, 70% and 80% of shade). The experimental design was completely randomized in four replicates on the experiments 1, 2, 3 and 4 conducted in a greenhouse and three replicates for the experiments 5, 6, 7 and 8 in the external environment to a greenhouse. In experiments 1 and 3, both species have continued forming nodules after flowering, the plants of these treatments Fni Ep2, Sni Ep2 and Si Ep2 had the highest average for the number, volume, fresh weight and dry weight of nodules. As the activity of the nodules, the plants of treatments Fi Ep1 and Si Ep1 had the highest number of active nodules compared to treatments Fni Ep2 and Sni Ep2. Assessing the effect of shading in experiments 2 and 4, it was found that bean and soybean plants have behaved differently. The shading of 80% favored the formation of nodules in inoculated bean deferring between treatments of shading, in contrast to the soybean plants that there was no difference (p ≥ 0.05) among treatments. There was no statistical difference between treatments in the number of active nodes for the beans; the plants of the Sni treatment 80% had the lowest number of active nodules compared to the plants of treatment Si 0%. In experiments 5 and 7 plants of soybeans and reduced the number of nodules after flowering, and as in Experiment 1 and 3 there was a higher number of active nodes during the growing season compared to the reproductive period. The shading applied in bean plants (Experiment 6) was not enough to cause no difference between treatments on the number and activity of nodules; in the experiment with 8 soybean, the shading changed patterns of nodulation and activity of nodules (p ≥ 0.05). It is this work that the formation and maintenance of activity of the nodules were so distinct in vegetative and reproductive stages, but the shading of 70 and 80% applied was not sufficient to cause significant change in activity of the nodules, suggesting that the reduction the availability of fotossintatos is not the limiting factor in determining the efficiency of N, mainly in the bean / A soja e o feijão são leguminosas de grande importância econômica e social para o Brasil. Do ponto de vista nutricional, são muito exigentes em nitrogênio e para suprir esta demanda ambas às espécies são hábeis em fixá-lo simbioticamente. Mas, para fixar simbioticamente o nitrogênio, os rizóbios necessitam de energia de carboidratos proveniente da fotossíntese. Por esta razão a disponibilidade de fotossintato é o maior fator limitante na Fixação Biológica de Nitrogênio (FBN). Este trabalho se propôs a avaliar a influência da inoculação com rizóbios em dois estádios fenológicos de plantas submetidas a diferentes níveis de sombreamento. Neste contexto foi avaliada a inoculação mediante os seguintes tratamentos: duas espécies de leguminosas (Phaseolus vulgaris, L. e Glycine max, L.) estando elas inoculadas e não inoculadas (Fi, Fni, Si e Sni) com estirpes específicas (Rhizobium tropici e Bradyrhizobium japonicum e B. elkanii) em dois estádios fenológicos (antes, Ep1, e após a floração, Ep2) e submetidas à três níveis de sombreamento (sem sombreamento, 70% e 80% de sombra). O delineamento experimental utilizado foi o inteiramente casualizado com quatro repetições para os experimentos 1, 2, 3 e 4 conduzidos em casa de vegetação e três repetições para os experimentos 5, 6, 7 e 8 conduzidos em ambiente externo a casa de vegetação. Nos experimentos 1 e 3, ambas as espécies continuaram formando nódulos após a floração, nestes as plantas dos tratamentos Fni Ep2, Sni Ep2 e Si Ep2 apresentaram as maiores médias para o número, volume, massa fresca e massa seca de nódulos. Quanto à atividade dos nódulos, as plantas dos tratamentos Fi Ep1 e Si Ep1 apresentaram o maior número de nódulos ativos comparados aos tratamentos Fni Ep2 e Sni Ep2. Avaliando o efeito do sombreamento nos experimentos 2 e 4, observou-se que as plantas de feijão e soja se comportaram de forma diferente. O sombreamento de 80% favoreceu a formação de nódulos no feijoeiro inoculado deferindo entre os tratamentos de sombreamento, ao contrário das plantas de soja que não houve diferença (p ≥ 0,05) entre os tratamentos. Não houve diferença estatística entre os tratamentos quanto ao número de nódulos ativos para o feijão; as plantas do tratamento Sni 80% obtiveram o menor número de nódulos ativos comparado às plantas do tratamento Si 0%. Nos experimentos 5 e 7 as plantas de feijão e soja reduziram o número de nódulos após a floração, e assim como no experimento 1 e 3, observou-se maior número de nódulos ativos durante o período vegetativo comparado ao período reprodutivo. O sombreamento aplicado nas plantas de feijão (Experimento 6) não foi suficiente para causar nenhuma diferença entre os tratamentos quanto ao número e atividade dos nódulos; no experimento 8 com soja, o sombreamento alterou os padrões de nodulação e atividade dos nódulos (p ≥ 0,05). Conclui-se neste trabalho, que a formação e manutenção da atividade dos nódulos ocorreram de maneira distinta nos estádios vegetativos e reprodutivos, contudo o sombreamento de 70 e 80% aplicado não foi suficiente para causar alteração notável na atividade dos nódulos, sugerindo que a redução na disponibilidade de fotossintatos não é o fator limitante na eficiência de fixação do N, principalmente no feijoeiro

Orientador: Marcelo Carvalho Minhoto Teixeira Filho / Resumo: Alternative management practices are needed to minimize the need for chemical fertilizer use in non-leguminous cropping systems. The use of biological agents which can fix atmospheric nitrogen and promote plant growth has shown potential as an option to improve soil nutrient availability to grass crops. In recent years, studies investigating the effects of silicon (Si) have increased substantially, especially in grain crops. This increased interest in Si is likely due to the beneficial effects of Si application on plant resistance to abiotic and biotic stresses, reflecting on greater plant development. This research was developed to investigate if inoculation of corn and wheat with Azospirillum brasilense associated with Si can enhance nitrogen use efficiency (NUE) and improve plant nutrition and yield, leading to a greater economic profit. The study was set up in a Rhodic Haplustox under no-till system, located in Selvíria, state of Mato Grosso do Sul, Brazil. The field trial took place during the 2015/16 (November-March), 2016 (April-September), 2016/17 (November-March) and 2017 April-September) seasons, with corn and wheat crops in sucession (spring/summer and winter seasons for corn and wheat, respectively). Treatments were tested in a randomized completely block design with four replicates, arranged in a full factorial design 5 × 2 × 2 and included: i) five N application rates, as urea source, applied in side-dressing (0, 50, 100, 150 and 200 kg ha-1); ii) two liming sou... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor