Efeito do óleo essencial de eucalipto e de substâncias húmicas no crescimento de Brachiaria e Estilosantes em diferentes condições hídricas

• Autor(a) principal: Praca, Nayara Maria Pedrosa
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/13198
• topic: Agronomia; Bioestimulantes; Forrageiras; Recuperação de pastagem; Substâncias húmicas; Óleo essencial de eucalipto; Crescimento de planta; Bioestimulação; Humic substances; Eucalyptus essential oil; Plant growth; Biostimulation; Forages; subject.br-rjbn

Generally degradation of pastures is associated with factors related to the establishment of forage and management, causing a decline in the natural fertility of the soil, which leads to the degradation of these areas exploited by livestock. Within the principles of soil conservation, the use of biostimulants of vegetative growth and the cycling of nutrients by green manuring, are proving increasingly favorable in the development of sustainable technologies. The objective of this work was to develop, evaluate and validate biotechnologies integrating the use of humic substances extracted from vermicompost and eucalyptus essential oil in the initial growth of the grass Brachiaria brizantha cv. Marandu and in the leguminosa Estilosantes cv. Campo Grande. In chapter 1, humic substances extracted from vermicompost (SH) and eucalyptus essential oil (OEE) were used as vegetable biostimulants. In Chapter 2 and 3 the effect of the application of humic substances and eucalyptus essential oil on the growth and development of Brachiaria brizantha cv. Marandu and Estilosantes cv. Campo Grande, respectively, in different levels of soil moisture (70%, 49% and 28% VTPOA). The parameters analyzed were aerial and root dry mass, plant height, gas exchange measurements and carbon (C) and nitrogen (N) analysis. In Chapter 1, the main functional groups present in the humic substances were found, the stretching of -OH, stretching of C = O of -COOH groups, C = C stretch of aromatic groups, C-N-H stretch of amides, C-O stretching of carboxylic acids and polysaccharides. UV-visible analysis showed that SHs exhibit high structural condensation, ie, a large number of aromatic structures compared to aliphatic structures, due to a high degree of humification. By means of mass spectrometry, the 1,8-Cineole compound, identified in the OEE, was considered the majority, representing 88.03% of the total compounds. In chapter 2 the use of humic substances provided greater accumulation of N in the plant biomass of the plants of Brachiaria brizantha cv. Marandu, increasing 53.48% of the accumulation of N in the aerial part of the plants when compared to the control treatment. In Chapter 3, the application of OEE and SH promoted a higher production of MSPA, with a difference of 57.8% and 35.2%, respectively, over MS when compared to control. They also provided favorable results for MSPR production and nodulation increase.