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Publication
Efeito da bactéria Methylobacterium symbioticum na adubação azotada em laranjeiras
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Advisor(s)
Abstract(s)
A necessidade de estratégias sustentáveis na agricultura tem despertado o interesse em
explorar o potencial das bactérias fixadoras de azoto como uma alternativa promissora na
redução da dependência de fertilizantes químicos e no aumento da produtividade das
culturas. A Methylobacterium simbioticum sp. nov é uma bactéria isolada dos esporos de um
fungo micorrízico arbuscular, Glomus iranicum var. tenuihypharum, que induz uma
biomassa vegetal elevada, levando a rendimentos mais elevados não apenas em culturas
anuais, mas também em culturas perenes. O objetivo deste trabalho foi estudar o efeito dessa
bactéria na capacidade de fixação do azoto e o efeito no crescimento de árvores de laranjeira.
O ensaio foi realizado em estufa de viveiros de árvores de fruto, localizada na Lousã. O
delineamento experimental utilizado foi totalmente casualizado com cinco repetições. Foram
ensaiados dois fatores: fertilização azotada com 5 níveis de fator (100 %, 90 %, 80 %, 60 %
e 50 % da dose de azoto recomendada para a cultura) e uma aplicação com Methylobacterium
symbioticum, com 1 nível de fator (100 %). O ensaio teve início em julho e terminou em
setembro de 2023. Durante esse período, foram realizadas observaçoes semanais, da altura
das plantas, diâmetro basal e área foliar. No final do ensaio realizou-se uma análise à seiva.
Embora não tenham sido observadas diferenças significativas entre tratamentos no que
respeita aos parâmetros analisados, os resultados sugerem uma influência positiva no
crescimento das plantas com a aplicação da Methylobacterium sp., especialmente no
tratamento com redução de 40 % de azoto. Contudo, esses resultados não se mostraram com
expressão suficiente para concluir um efeito positivo da utilização da bactéria quanto aos
parâmetros avaliados. Assim, recomenda-se a realização de novos estudos para avaliar a
eficácia da bactéria Methylobacterium sp., para esta e outras culturas.
The need for sustainable strategies in agriculture has sparked interest in exploring the potential of nitrogen-fixing bacteria as a promising alternative for reducing dependence on chemical fertilizers and increasing crop productivity. Methylobacterium symbioticum sp. nov is a bacterium isolated from the spores of an arbuscular mycorrhizal fungus, Glomus iranicum var. tenuihypharum, which induces high plant biomass, leading to higher yields not only in annual crops but also in perennial crops. The objective of this work was to study the effect of this bacteria on the nitrogen fixation capacity and the effect on the growth of orange trees. The test was carried out in a fruit tree nursery greenhouse, located in Lousã. The experimental design used was completely randomized with five replications. Two factors were tested: nitrogen fertilization with 5 factor levels (100 %, 90 %, 80 %, 60 % and 50 % of the recommended nitrogen dose for the crop) and an application with Methylobacterium symbioticum, with 1 factor level (100 %). The trial began in July and ended in September 2023. During this period, weekly observations of plant height, basal diameter and leaf area were carried out. At the end of the test, a sap analysis was carried out. Although no significant differences were observed between treatments with regard to the analyzed parameters, the results suggest a positive influence on plant growth with the application of Methylobacterium sp., especially in the treatment with a 40 % nitrogen reduction. However, these results were not sufficiently expressive to conclude a positive effect of using the bacteria in terms of the parameters evaluated. Therefore, it is recommended that new studies be carried out to evaluate the effectiveness of the bacteria Methylobacterium sp., for this and other cultures.
The need for sustainable strategies in agriculture has sparked interest in exploring the potential of nitrogen-fixing bacteria as a promising alternative for reducing dependence on chemical fertilizers and increasing crop productivity. Methylobacterium symbioticum sp. nov is a bacterium isolated from the spores of an arbuscular mycorrhizal fungus, Glomus iranicum var. tenuihypharum, which induces high plant biomass, leading to higher yields not only in annual crops but also in perennial crops. The objective of this work was to study the effect of this bacteria on the nitrogen fixation capacity and the effect on the growth of orange trees. The test was carried out in a fruit tree nursery greenhouse, located in Lousã. The experimental design used was completely randomized with five replications. Two factors were tested: nitrogen fertilization with 5 factor levels (100 %, 90 %, 80 %, 60 % and 50 % of the recommended nitrogen dose for the crop) and an application with Methylobacterium symbioticum, with 1 factor level (100 %). The trial began in July and ended in September 2023. During this period, weekly observations of plant height, basal diameter and leaf area were carried out. At the end of the test, a sap analysis was carried out. Although no significant differences were observed between treatments with regard to the analyzed parameters, the results suggest a positive influence on plant growth with the application of Methylobacterium sp., especially in the treatment with a 40 % nitrogen reduction. However, these results were not sufficiently expressive to conclude a positive effect of using the bacteria in terms of the parameters evaluated. Therefore, it is recommended that new studies be carried out to evaluate the effectiveness of the bacteria Methylobacterium sp., for this and other cultures.
Description
Dissertação de Mestrado na área da Engenharia Agronómica, apresentada na Escola Superior Agrária de Santarém
Keywords
Citrus sinensis laranjeira bactéria fixadora de azoto Experimentação de campo orange tree nitrogen-fixing bacteria
Citation
Primo, Nuno José Alves Quaresma Rodrigues(2024). Efeito da bactéria Methylobacterium symbioticum na adubação azotada em laranjeiras. Dissertação apresentada para obtenção do grau de Mestre na área de Engenharia Agronómica, na Escola Superior Agrária de Santarém